Pull blockchain changes into berkeleydb branch

72 files changed, 17743 insertions, 107 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9e29dab59..3b360d38a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -65,6 +65,21 @@ option(BOOST_IGNORE_SYSTEM_PATHS "Ignore boost system paths for local boost inst
 set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 enable_testing()
 
+# Check whether we're on a 32-bit or 64-bit system
+if(CMAKE_SIZEOF_VOID_P EQUAL "8")
+  set(DEFAULT_BUILD_64 ON)
+else()
+  set(DEFAULT_BUILD_64 OFF)
+endif()
+option(BUILD_64 "Build for 64-bit? 'OFF' builds for 32-bit." ${DEFAULT_BUILD_64})
+
+if(BUILD_64)
+  set(ARCH_WIDTH "64")
+else()
+  set(ARCH_WIDTH "32")
+endif()
+message(STATUS "Building for a ${ARCH_WIDTH}-bit system")
+
 # Check if we're on FreeBSD so we can exclude the local miniupnpc (it should be installed from ports instead)
 # CMAKE_SYSTEM_NAME checks are commonly known, but specifically taken from libsdl's CMakeLists
 if(CMAKE_SYSTEM_NAME MATCHES "kFreeBSD.*")
@@ -96,16 +111,16 @@ endif()
 option(STATIC "Link libraries statically" ${DEFAULT_STATIC})
 
 if(MINGW)
-  get_filename_component(msys2_install_path "[HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\MSYS2 64bit;InstallLocation]" ABSOLUTE)
-  set(CMAKE_INCLUDE_PATH "${msys2_install_path}/mingw64/include")
+  get_filename_component(msys2_install_path "[HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\MSYS2 ${ARCH_WIDTH}bit;InstallLocation]" ABSOLUTE)
+  set(CMAKE_INCLUDE_PATH "${msys2_install_path}/mingw${ARCH_WIDTH}/include")
   # This is necessary because otherwise CMake will make Boost libraries -lfoo
   # rather than a full path. Unfortunately, this makes the shared libraries get
   # linked due to a bug in CMake which misses putting -static flags around the
   # -lfoo arguments.
   list(REMOVE_ITEM CMAKE_C_IMPLICIT_LINK_DIRECTORIES
-    "${msys2_install_path}/mingw64/lib")
+    "${msys2_install_path}/mingw${ARCH_WIDTH}/lib")
   list(REMOVE_ITEM CMAKE_CXX_IMPLICIT_LINK_DIRECTORIES
-    "${msys2_install_path}/mingw64/lib")
+    "${msys2_install_path}/mingw${ARCH_WIDTH}/lib")
 endif()
 
 if(STATIC)
diff --git a/external/CMakeLists.txt b/external/CMakeLists.txt
index 527c5b5a9..245758d9f 100644
--- a/external/CMakeLists.txt
+++ b/external/CMakeLists.txt
@@ -99,12 +99,3 @@ else()
 endif()
 
 add_subdirectory(db_drivers)
-set(LMDB_STATIC ${LMDB_STATIC} PARENT_SCOPE)
-set(LMDB_INCLUDE ${LMDB_INCLUDE} PARENT_SCOPE)
-set(LMDB_LIBRARY ${LMDB_LIBRARY} PARENT_SCOPE)
-set(LMDB_LIBRARY_DIRS ${LMDB_LIBRARY_DIRS} PARENT_SCOPE)
-
-set(BDB_STATIC ${BDB_STATIC} PARENT_SCOPE)
-set(BDB_INCLUDE ${BDB_INCLUDE} PARENT_SCOPE)
-set(BDB_LIBRARY ${BDB_LIBRARY} PARENT_SCOPE)
-set(BDB_LIBRARY_DIRS ${BDB_LIBRARY_DIRS} PARENT_SCOPE)
diff --git a/external/db_drivers/CMakeLists.txt b/external/db_drivers/CMakeLists.txt
index f90f9f136..b6865a037 100644
--- a/external/db_drivers/CMakeLists.txt
+++ b/external/db_drivers/CMakeLists.txt
@@ -26,27 +26,13 @@
 # STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 # THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-find_package(LMDB)
+# We aren't even going to check the system for an installed LMDB driver, as it is too
+# critical a consensus component to rely on dynamically linked libraries
+message(STATUS "Using ${ARCH_WIDTH}-bit LMDB from source tree")
+add_subdirectory(liblmdb${ARCH_WIDTH})
+set(LMDB_INCLUDE "${CMAKE_CURRENT_SOURCE_DIR}/liblmdb${ARCH_WIDTH}" CACHE STRING "LMDB Include path")
 
-if(NOT LMDB_LIBRARIES OR STATIC)
-  add_subdirectory(liblmdb)
-  message(STATUS "lmdb not found, building from src tree")
-
-  set(LMDB_STATIC true PARENT_SCOPE)
-  set(LMDB_INCLUDE "${CMAKE_CURRENT_SOURCE_DIR}/liblmdb" PARENT_SCOPE)
-  set(LMDB_LIBRARY "lmdb" PARENT_SCOPE)
-else()
-  message(STATUS "Found liblmdb include (lmdb.h) in ${LMDB_INCLUDE_DIR}")
-  if(LMDB_LIBRARIES)
-    message(STATUS "Found liblmdb shared library")
-    set(LMDB_STATIC false PARENT_SCOPE)
-    set(LMDB_INCLUDE ${LMDB_INCLUDE_DIR} PARENT_SCOPE)
-    set(LMDB_LIBRARY ${LMDB_LIBRARIES} PARENT_SCOPE)
-    set(LMDB_LIBRARY_DIRS "" PARENT_SCOPE)
-  else()
-    die("Found liblmdb includes, but could not find liblmdb library. Please make sure you have installed liblmdb and liblmdb-dev or the equivalent")
-  endif()
-endif()
+set(LMDB_LIBRARY "lmdb" CACHE STRING "LMDB Library name")
 
 find_package(BerkeleyDB)
 
@@ -54,17 +40,17 @@ if(NOT BERKELEY_DB_LIBRARIES OR STATIC)
   add_subdirectory(libdb)
   message(STATUS "BerkeleyDB not found, building from src tree")
 
-  set(BDB_STATIC true PARENT_SCOPE)
-  set(BDB_INCLUDE "${CMAKE_CURRENT_SOURCE_DIR}/libdb" PARENT_SCOPE)
-  set(BDB_LIBRARY "db" PARENT_SCOPE)
+  set(BDB_STATIC true CACHE BOOL "BDB Static flag")
+  set(BDB_INCLUDE "${CMAKE_CURRENT_SOURCE_DIR}/libdb" CACHE STRING "BDB include path")
+  set(BDB_LIBRARY "db" CACHE STRING "BDB library name")
 else()
   message(STATUS "Found BerkeleyDB include (db.h) in ${BERKELEY_DB_INCLUDE_DIR}")
   if(BERKELEY_DB_LIBRARIES)
     message(STATUS "Found BerkeleyDB shared library")
-    set(BDB_STATIC false PARENT_SCOPE)
-    set(BDB_INCLUDE ${BERKELEY_DB_INCLUDE_DIR} PARENT_SCOPE)
-    set(BDB_LIBRARY ${BERKELEY_DB_LIBRARIES} PARENT_SCOPE)
-    set(BDB_LIBRARY_DIRS "" PARENT_SCOPE)
+    set(BDB_STATIC false CACHE BOOL "BDB Static flag")
+    set(BDB_INCLUDE ${BERKELEY_DB_INCLUDE_DIR} CACHE STRING "BDB include path")
+    set(BDB_LIBRARY ${BERKELEY_DB_LIBRARIES} CACHE STRING "BDB library name")
+    set(BDB_LIBRARY_DIRS "" CACHE STRING "BDB Library dirs")
   else()
     die("Found BerkeleyDB includes, but could not find BerkeleyDB library. Please make sure you have installed libdb and libdb-dev or the equivalent")
   endif()
diff --git a/external/db_drivers/liblmdb32/.gitignore b/external/db_drivers/liblmdb32/.gitignore
new file mode 100644
index 000000000..f3277afe4
--- /dev/null
+++ b/external/db_drivers/liblmdb32/.gitignore
@@ -0,0 +1,20 @@
+mtest
+mtest[23456]
+testdb
+mdb_copy
+mdb_stat
+*.[ao]
+*.so
+*.exe
+*[~#]
+*.bak
+*.orig
+*.rej
+*.gcov
+*.gcda
+*.gcno
+core
+core.*
+valgrind.*
+man/
+html/
diff --git a/external/db_drivers/liblmdb/CHANGES b/external/db_drivers/liblmdb32/CHANGES
index 34049ba7a..34049ba7a 100644
--- a/external/db_drivers/liblmdb/CHANGES
+++ b/external/db_drivers/liblmdb32/CHANGES
diff --git a/external/db_drivers/liblmdb/CMakeLists.txt b/external/db_drivers/liblmdb32/CMakeLists.txt
index 62b800135..62b800135 100644
--- a/external/db_drivers/liblmdb/CMakeLists.txt
+++ b/external/db_drivers/liblmdb32/CMakeLists.txt
diff --git a/external/db_drivers/liblmdb/COPYRIGHT b/external/db_drivers/liblmdb32/COPYRIGHT
index e0eb484c7..e0eb484c7 100644
--- a/external/db_drivers/liblmdb/COPYRIGHT
+++ b/external/db_drivers/liblmdb32/COPYRIGHT
diff --git a/external/db_drivers/liblmdb/Doxyfile b/external/db_drivers/liblmdb32/Doxyfile
index 92d17b09e..92d17b09e 100644
--- a/external/db_drivers/liblmdb/Doxyfile
+++ b/external/db_drivers/liblmdb32/Doxyfile
diff --git a/external/db_drivers/liblmdb/LICENSE b/external/db_drivers/liblmdb32/LICENSE
index 05ad7571e..05ad7571e 100644
--- a/external/db_drivers/liblmdb/LICENSE
+++ b/external/db_drivers/liblmdb32/LICENSE
diff --git a/external/db_drivers/liblmdb32/Makefile b/external/db_drivers/liblmdb32/Makefile
new file mode 100644
index 000000000..095e65587
--- /dev/null
+++ b/external/db_drivers/liblmdb32/Makefile
@@ -0,0 +1,98 @@
+# Makefile for liblmdb (Lightning memory-mapped database library).
+
+########################################################################
+# Configuration. The compiler options must enable threaded compilation.
+#
+# Preprocessor macros (for CPPFLAGS) of interest...
+# Note that the defaults should already be correct for most
+# platforms; you should not need to change any of these.
+# Read their descriptions in mdb.c if you do:
+#
+# - MDB_USE_POSIX_SEM
+# - MDB_DSYNC
+# - MDB_FDATASYNC
+# - MDB_USE_PWRITEV
+#
+# There may be other macros in mdb.c of interest. You should
+# read mdb.c before changing any of them.
+#
+CC	= gcc
+W	= -W -Wall -Wno-unused-parameter -Wbad-function-cast -Wuninitialized
+THREADS = -pthread
+OPT = -O2 -g
+CFLAGS	= $(THREADS) $(OPT) $(W) $(XCFLAGS)
+LDLIBS	=
+SOLIBS	=
+prefix	= /usr/local
+XCFLAGS = -DVL32
+
+########################################################################
+
+IHDRS	= lmdb.h
+ILIBS	= liblmdb.a liblmdb.so
+IPROGS	= mdb_stat mdb_copy mdb_dump mdb_load
+IDOCS	= mdb_stat.1 mdb_copy.1 mdb_dump.1 mdb_load.1
+PROGS	= $(IPROGS) mtest mtest2 mtest3 mtest4 mtest5
+all:	$(ILIBS) $(PROGS)
+
+install: $(ILIBS) $(IPROGS) $(IHDRS)
+	for f in $(IPROGS); do cp $$f $(DESTDIR)$(prefix)/bin; done
+	for f in $(ILIBS); do cp $$f $(DESTDIR)$(prefix)/lib; done
+	for f in $(IHDRS); do cp $$f $(DESTDIR)$(prefix)/include; done
+	for f in $(IDOCS); do cp $$f $(DESTDIR)$(prefix)/man/man1; done
+
+clean:
+	rm -rf $(PROGS) *.[ao] *.so *~ testdb
+
+test:	all
+	mkdir testdb
+	./mtest && ./mdb_stat testdb
+
+liblmdb.a:	mdb.o midl.o
+	ar rs $@ mdb.o midl.o
+
+liblmdb.so:	mdb.o midl.o
+#	$(CC) $(LDFLAGS) -pthread -shared -Wl,-Bsymbolic -o $@ mdb.o midl.o $(SOLIBS)
+	$(CC) $(LDFLAGS) -pthread -shared -o $@ mdb.o midl.o $(SOLIBS)
+
+mdb_stat: mdb_stat.o liblmdb.a
+mdb_copy: mdb_copy.o liblmdb.a
+mdb_dump: mdb_dump.o liblmdb.a
+mdb_load: mdb_load.o liblmdb.a
+mtest:    mtest.o    liblmdb.a
+mtest2:	mtest2.o liblmdb.a
+mtest3:	mtest3.o liblmdb.a
+mtest4:	mtest4.o liblmdb.a
+mtest5:	mtest5.o liblmdb.a
+mtest6:	mtest6.o liblmdb.a
+
+mdb.o: mdb.c lmdb.h midl.h
+	$(CC) $(CFLAGS) -fPIC $(CPPFLAGS) -c mdb.c
+
+midl.o: midl.c midl.h
+	$(CC) $(CFLAGS) -fPIC $(CPPFLAGS) -c midl.c
+
+%:	%.o
+	$(CC) $(CFLAGS) $(LDFLAGS) $^ $(LDLIBS) -o $@
+
+%.o:	%.c lmdb.h
+	$(CC) $(CFLAGS) $(CPPFLAGS) -c $<
+
+COV_FLAGS=-fprofile-arcs -ftest-coverage
+COV_OBJS=xmdb.o xmidl.o
+
+coverage: xmtest
+	for i in mtest*.c [0-9]*.c; do j=`basename \$$i .c`; $(MAKE) $$j.o; \
+		gcc -o x$$j $$j.o $(COV_OBJS) -pthread $(COV_FLAGS); \
+		rm -rf testdb; mkdir testdb; ./x$$j; done
+	gcov xmdb.c
+	gcov xmidl.c
+
+xmtest:	mtest.o xmdb.o xmidl.o
+	gcc -o xmtest mtest.o xmdb.o xmidl.o -pthread $(COV_FLAGS)
+
+xmdb.o: mdb.c lmdb.h midl.h
+	$(CC) $(CFLAGS) -fPIC $(CPPFLAGS) -O0 $(COV_FLAGS) -c mdb.c -o $@
+
+xmidl.o: midl.c midl.h
+	$(CC) $(CFLAGS) -fPIC $(CPPFLAGS) -O0 $(COV_FLAGS) -c midl.c -o $@
diff --git a/external/db_drivers/liblmdb32/lmdb.h b/external/db_drivers/liblmdb32/lmdb.h
new file mode 100644
index 000000000..bdbb0b909
--- /dev/null
+++ b/external/db_drivers/liblmdb32/lmdb.h
@@ -0,0 +1,1553 @@
+/** @file lmdb.h
+ *	@brief Lightning memory-mapped database library
+ *
+ *	@mainpage	Lightning Memory-Mapped Database Manager (LMDB)
+ *
+ *	@section intro_sec Introduction
+ *	LMDB is a Btree-based database management library modeled loosely on the
+ *	BerkeleyDB API, but much simplified. The entire database is exposed
+ *	in a memory map, and all data fetches return data directly
+ *	from the mapped memory, so no malloc's or memcpy's occur during
+ *	data fetches. As such, the library is extremely simple because it
+ *	requires no page caching layer of its own, and it is extremely high
+ *	performance and memory-efficient. It is also fully transactional with
+ *	full ACID semantics, and when the memory map is read-only, the
+ *	database integrity cannot be corrupted by stray pointer writes from
+ *	application code.
+ *
+ *	The library is fully thread-aware and supports concurrent read/write
+ *	access from multiple processes and threads. Data pages use a copy-on-
+ *	write strategy so no active data pages are ever overwritten, which
+ *	also provides resistance to corruption and eliminates the need of any
+ *	special recovery procedures after a system crash. Writes are fully
+ *	serialized; only one write transaction may be active at a time, which
+ *	guarantees that writers can never deadlock. The database structure is
+ *	multi-versioned so readers run with no locks; writers cannot block
+ *	readers, and readers don't block writers.
+ *
+ *	Unlike other well-known database mechanisms which use either write-ahead
+ *	transaction logs or append-only data writes, LMDB requires no maintenance
+ *	during operation. Both write-ahead loggers and append-only databases
+ *	require periodic checkpointing and/or compaction of their log or database
+ *	files otherwise they grow without bound. LMDB tracks free pages within
+ *	the database and re-uses them for new write operations, so the database
+ *	size does not grow without bound in normal use.
+ *
+ *	The memory map can be used as a read-only or read-write map. It is
+ *	read-only by default as this provides total immunity to corruption.
+ *	Using read-write mode offers much higher write performance, but adds
+ *	the possibility for stray application writes thru pointers to silently
+ *	corrupt the database. Of course if your application code is known to
+ *	be bug-free (...) then this is not an issue.
+ *
+ *	@section caveats_sec Caveats
+ *	Troubleshooting the lock file, plus semaphores on BSD systems:
+ *
+ *	- A broken lockfile can cause sync issues.
+ *	  Stale reader transactions left behind by an aborted program
+ *	  cause further writes to grow the database quickly, and
+ *	  stale locks can block further operation.
+ *
+ *	  Fix: Check for stale readers periodically, using the
+ *	  #mdb_reader_check function or the \ref mdb_stat_1 "mdb_stat" tool. Or just
+ *	  make all programs using the database close it; the lockfile
+ *	  is always reset on first open of the environment.
+ *
+ *	- On BSD systems or others configured with MDB_USE_POSIX_SEM,
+ *	  startup can fail due to semaphores owned by another userid.
+ *
+ *	  Fix: Open and close the database as the user which owns the
+ *	  semaphores (likely last user) or as root, while no other
+ *	  process is using the database.
+ *
+ *	Restrictions/caveats (in addition to those listed for some functions):
+ *
+ *	- Only the database owner should normally use the database on
+ *	  BSD systems or when otherwise configured with MDB_USE_POSIX_SEM.
+ *	  Multiple users can cause startup to fail later, as noted above.
+ *
+ *	- There is normally no pure read-only mode, since readers need write
+ *	  access to locks and lock file. Exceptions: On read-only filesystems
+ *	  or with the #MDB_NOLOCK flag described under #mdb_env_open().
+ *
+ *	- By default, in versions before 0.9.10, unused portions of the data
+ *	  file might receive garbage data from memory freed by other code.
+ *	  (This does not happen when using the #MDB_WRITEMAP flag.) As of
+ *	  0.9.10 the default behavior is to initialize such memory before
+ *	  writing to the data file. Since there may be a slight performance
+ *	  cost due to this initialization, applications may disable it using
+ *	  the #MDB_NOMEMINIT flag. Applications handling sensitive data
+ *	  which must not be written should not use this flag. This flag is
+ *	  irrelevant when using #MDB_WRITEMAP.
+ *
+ *	- A thread can only use one transaction at a time, plus any child
+ *	  transactions.  Each transaction belongs to one thread.  See below.
+ *	  The #MDB_NOTLS flag changes this for read-only transactions.
+ *
+ *	- Use an MDB_env* in the process which opened it, without fork()ing.
+ *
+ *	- Do not have open an LMDB database twice in the same process at
+ *	  the same time.  Not even from a plain open() call - close()ing it
+ *	  breaks flock() advisory locking.
+ *
+ *	- Avoid long-lived transactions.  Read transactions prevent
+ *	  reuse of pages freed by newer write transactions, thus the
+ *	  database can grow quickly.  Write transactions prevent
+ *	  other write transactions, since writes are serialized.
+ *
+ *	- Avoid suspending a process with active transactions.  These
+ *	  would then be "long-lived" as above.  Also read transactions
+ *	  suspended when writers commit could sometimes see wrong data.
+ *
+ *	...when several processes can use a database concurrently:
+ *
+ *	- Avoid aborting a process with an active transaction.
+ *	  The transaction becomes "long-lived" as above until a check
+ *	  for stale readers is performed or the lockfile is reset,
+ *	  since the process may not remove it from the lockfile.
+ *
+ *	- If you do that anyway, do a periodic check for stale readers. Or
+ *	  close the environment once in a while, so the lockfile can get reset.
+ *
+ *	- Do not use LMDB databases on remote filesystems, even between
+ *	  processes on the same host.  This breaks flock() on some OSes,
+ *	  possibly memory map sync, and certainly sync between programs
+ *	  on different hosts.
+ *
+ *	- Opening a database can fail if another process is opening or
+ *	  closing it at exactly the same time.
+ *
+ *	@author	Howard Chu, Symas Corporation.
+ *
+ *	@copyright Copyright 2011-2014 Howard Chu, Symas Corp. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ *
+ *	@par Derived From:
+ * This code is derived from btree.c written by Martin Hedenfalk.
+ *
+ * Copyright (c) 2009, 2010 Martin Hedenfalk <martin@bzero.se>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#ifndef _LMDB_H_
+#define _LMDB_H_
+
+#include <sys/types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Unix permissions for creating files, or dummy definition for Windows */
+#ifdef _MSC_VER
+typedef	int	mdb_mode_t;
+#else
+typedef	mode_t	mdb_mode_t;
+#endif
+
+/** An abstraction for a file handle.
+ *	On POSIX systems file handles are small integers. On Windows
+ *	they're opaque pointers.
+ */
+#ifdef _WIN32
+typedef	void *mdb_filehandle_t;
+#else
+typedef int mdb_filehandle_t;
+#endif
+
+/** @defgroup mdb LMDB API
+ *	@{
+ *	@brief OpenLDAP Lightning Memory-Mapped Database Manager
+ */
+/** @defgroup Version Version Macros
+ *	@{
+ */
+/** Library major version */
+#define MDB_VERSION_MAJOR	0
+/** Library minor version */
+#define MDB_VERSION_MINOR	9
+/** Library patch version */
+#define MDB_VERSION_PATCH	14
+
+/** Combine args a,b,c into a single integer for easy version comparisons */
+#define MDB_VERINT(a,b,c)	(((a) << 24) | ((b) << 16) | (c))
+
+/** The full library version as a single integer */
+#define MDB_VERSION_FULL	\
+	MDB_VERINT(MDB_VERSION_MAJOR,MDB_VERSION_MINOR,MDB_VERSION_PATCH)
+
+/** The release date of this library version */
+#define MDB_VERSION_DATE	"September 20, 2014"
+
+/** A stringifier for the version info */
+#define MDB_VERSTR(a,b,c,d)	"LMDB " #a "." #b "." #c ": (" d ")"
+
+/** A helper for the stringifier macro */
+#define MDB_VERFOO(a,b,c,d)	MDB_VERSTR(a,b,c,d)
+
+/** The full library version as a C string */
+#define	MDB_VERSION_STRING	\
+	MDB_VERFOO(MDB_VERSION_MAJOR,MDB_VERSION_MINOR,MDB_VERSION_PATCH,MDB_VERSION_DATE)
+/**	@} */
+
+/** @brief Opaque structure for a database environment.
+ *
+ * A DB environment supports multiple databases, all residing in the same
+ * shared-memory map.
+ */
+typedef struct MDB_env MDB_env;
+
+/** @brief Opaque structure for a transaction handle.
+ *
+ * All database operations require a transaction handle. Transactions may be
+ * read-only or read-write.
+ */
+typedef struct MDB_txn MDB_txn;
+
+/** @brief A handle for an individual database in the DB environment. */
+typedef unsigned int	MDB_dbi;
+
+/** @brief Opaque structure for navigating through a database */
+typedef struct MDB_cursor MDB_cursor;
+
+/** @brief Generic structure used for passing keys and data in and out
+ * of the database.
+ *
+ * Values returned from the database are valid only until a subsequent
+ * update operation, or the end of the transaction. Do not modify or
+ * free them, they commonly point into the database itself.
+ *
+ * Key sizes must be between 1 and #mdb_env_get_maxkeysize() inclusive.
+ * The same applies to data sizes in databases with the #MDB_DUPSORT flag.
+ * Other data items can in theory be from 0 to 0xffffffff bytes long.
+ */
+typedef struct MDB_val {
+	size_t		 mv_size;	/**< size of the data item */
+	void		*mv_data;	/**< address of the data item */
+} MDB_val;
+
+/** @brief A callback function used to compare two keys in a database */
+typedef int  (MDB_cmp_func)(const MDB_val *a, const MDB_val *b);
+
+/** @brief A callback function used to relocate a position-dependent data item
+ * in a fixed-address database.
+ *
+ * The \b newptr gives the item's desired address in
+ * the memory map, and \b oldptr gives its previous address. The item's actual
+ * data resides at the address in \b item.  This callback is expected to walk
+ * through the fields of the record in \b item and modify any
+ * values based at the \b oldptr address to be relative to the \b newptr address.
+ * @param[in,out] item The item that is to be relocated.
+ * @param[in] oldptr The previous address.
+ * @param[in] newptr The new address to relocate to.
+ * @param[in] relctx An application-provided context, set by #mdb_set_relctx().
+ * @todo This feature is currently unimplemented.
+ */
+typedef void (MDB_rel_func)(MDB_val *item, void *oldptr, void *newptr, void *relctx);
+
+/** @defgroup	mdb_env	Environment Flags
+ *	@{
+ */
+	/** mmap at a fixed address (experimental) */
+#define MDB_FIXEDMAP	0x01
+	/** no environment directory */
+#define MDB_NOSUBDIR	0x4000
+	/** don't fsync after commit */
+#define MDB_NOSYNC		0x10000
+	/** read only */
+#define MDB_RDONLY		0x20000
+	/** don't fsync metapage after commit */
+#define MDB_NOMETASYNC		0x40000
+	/** use writable mmap */
+#define MDB_WRITEMAP		0x80000
+	/** use asynchronous msync when #MDB_WRITEMAP is used */
+#define MDB_MAPASYNC		0x100000
+	/** tie reader locktable slots to #MDB_txn objects instead of to threads */
+#define MDB_NOTLS		0x200000
+	/** don't do any locking, caller must manage their own locks */
+#define MDB_NOLOCK		0x400000
+	/** don't do readahead (no effect on Windows) */
+#define MDB_NORDAHEAD	0x800000
+	/** don't initialize malloc'd memory before writing to datafile */
+#define MDB_NOMEMINIT	0x1000000
+/** @} */
+
+/**	@defgroup	mdb_dbi_open	Database Flags
+ *	@{
+ */
+	/** use reverse string keys */
+#define MDB_REVERSEKEY	0x02
+	/** use sorted duplicates */
+#define MDB_DUPSORT		0x04
+	/** numeric keys in native byte order.
+	 *  The keys must all be of the same size. */
+#define MDB_INTEGERKEY	0x08
+	/** with #MDB_DUPSORT, sorted dup items have fixed size */
+#define MDB_DUPFIXED	0x10
+	/** with #MDB_DUPSORT, dups are numeric in native byte order */
+#define MDB_INTEGERDUP	0x20
+	/** with #MDB_DUPSORT, use reverse string dups */
+#define MDB_REVERSEDUP	0x40
+	/** create DB if not already existing */
+#define MDB_CREATE		0x40000
+/** @} */
+
+/**	@defgroup mdb_put	Write Flags
+ *	@{
+ */
+/** For put: Don't write if the key already exists. */
+#define MDB_NOOVERWRITE	0x10
+/** Only for #MDB_DUPSORT<br>
+ * For put: don't write if the key and data pair already exist.<br>
+ * For mdb_cursor_del: remove all duplicate data items.
+ */
+#define MDB_NODUPDATA	0x20
+/** For mdb_cursor_put: overwrite the current key/data pair */
+#define MDB_CURRENT	0x40
+/** For put: Just reserve space for data, don't copy it. Return a
+ * pointer to the reserved space.
+ */
+#define MDB_RESERVE	0x10000
+/** Data is being appended, don't split full pages. */
+#define MDB_APPEND	0x20000
+/** Duplicate data is being appended, don't split full pages. */
+#define MDB_APPENDDUP	0x40000
+/** Store multiple data items in one call. Only for #MDB_DUPFIXED. */
+#define MDB_MULTIPLE	0x80000
+/*	@} */
+
+/**	@defgroup mdb_copy	Copy Flags
+ *	@{
+ */
+/** Compacting copy: Omit free space from copy, and renumber all
+ * pages sequentially.
+ */
+#define MDB_CP_COMPACT	0x01
+/*	@} */
+
+/** @brief Cursor Get operations.
+ *
+ *	This is the set of all operations for retrieving data
+ *	using a cursor.
+ */
+typedef enum MDB_cursor_op {
+	MDB_FIRST,				/**< Position at first key/data item */
+	MDB_FIRST_DUP,			/**< Position at first data item of current key.
+								Only for #MDB_DUPSORT */
+	MDB_GET_BOTH,			/**< Position at key/data pair. Only for #MDB_DUPSORT */
+	MDB_GET_BOTH_RANGE,		/**< position at key, nearest data. Only for #MDB_DUPSORT */
+	MDB_GET_CURRENT,		/**< Return key/data at current cursor position */
+	MDB_GET_MULTIPLE,		/**< Return key and up to a page of duplicate data items
+								from current cursor position. Move cursor to prepare
+								for #MDB_NEXT_MULTIPLE. Only for #MDB_DUPFIXED */
+	MDB_LAST,				/**< Position at last key/data item */
+	MDB_LAST_DUP,			/**< Position at last data item of current key.
+								Only for #MDB_DUPSORT */
+	MDB_NEXT,				/**< Position at next data item */
+	MDB_NEXT_DUP,			/**< Position at next data item of current key.
+								Only for #MDB_DUPSORT */
+	MDB_NEXT_MULTIPLE,		/**< Return key and up to a page of duplicate data items
+								from next cursor position. Move cursor to prepare
+								for #MDB_NEXT_MULTIPLE. Only for #MDB_DUPFIXED */
+	MDB_NEXT_NODUP,			/**< Position at first data item of next key */
+	MDB_PREV,				/**< Position at previous data item */
+	MDB_PREV_DUP,			/**< Position at previous data item of current key.
+								Only for #MDB_DUPSORT */
+	MDB_PREV_NODUP,			/**< Position at last data item of previous key */
+	MDB_SET,				/**< Position at specified key */
+	MDB_SET_KEY,			/**< Position at specified key, return key + data */
+	MDB_SET_RANGE			/**< Position at first key greater than or equal to specified key. */
+} MDB_cursor_op;
+
+/** @defgroup  errors	Return Codes
+ *
+ *	BerkeleyDB uses -30800 to -30999, we'll go under them
+ *	@{
+ */
+	/**	Successful result */
+#define MDB_SUCCESS	 0
+	/** key/data pair already exists */
+#define MDB_KEYEXIST	(-30799)
+	/** key/data pair not found (EOF) */
+#define MDB_NOTFOUND	(-30798)
+	/** Requested page not found - this usually indicates corruption */
+#define MDB_PAGE_NOTFOUND	(-30797)
+	/** Located page was wrong type */
+#define MDB_CORRUPTED	(-30796)
+	/** Update of meta page failed, probably I/O error */
+#define MDB_PANIC		(-30795)
+	/** Environment version mismatch */
+#define MDB_VERSION_MISMATCH	(-30794)
+	/** File is not a valid LMDB file */
+#define MDB_INVALID	(-30793)
+	/** Environment mapsize reached */
+#define MDB_MAP_FULL	(-30792)
+	/** Environment maxdbs reached */
+#define MDB_DBS_FULL	(-30791)
+	/** Environment maxreaders reached */
+#define MDB_READERS_FULL	(-30790)
+	/** Too many TLS keys in use - Windows only */
+#define MDB_TLS_FULL	(-30789)
+	/** Txn has too many dirty pages */
+#define MDB_TXN_FULL	(-30788)
+	/** Cursor stack too deep - internal error */
+#define MDB_CURSOR_FULL	(-30787)
+	/** Page has not enough space - internal error */
+#define MDB_PAGE_FULL	(-30786)
+	/** Database contents grew beyond environment mapsize */
+#define MDB_MAP_RESIZED	(-30785)
+	/** MDB_INCOMPATIBLE: Operation and DB incompatible, or DB flags changed */
+#define MDB_INCOMPATIBLE	(-30784)
+	/** Invalid reuse of reader locktable slot */
+#define MDB_BAD_RSLOT		(-30783)
+	/** Transaction cannot recover - it must be aborted */
+#define MDB_BAD_TXN			(-30782)
+	/** Unsupported size of key/DB name/data, or wrong DUPFIXED size */
+#define MDB_BAD_VALSIZE		(-30781)
+	/** The specified DBI was changed unexpectedly */
+#define MDB_BAD_DBI		(-30780)
+	/** The last defined error code */
+#define MDB_LAST_ERRCODE	MDB_BAD_DBI
+/** @} */
+
+/** @brief Statistics for a database in the environment */
+typedef struct MDB_stat {
+	unsigned int	ms_psize;			/**< Size of a database page.
+											This is currently the same for all databases. */
+	unsigned int	ms_depth;			/**< Depth (height) of the B-tree */
+	size_t		ms_branch_pages;	/**< Number of internal (non-leaf) pages */
+	size_t		ms_leaf_pages;		/**< Number of leaf pages */
+	size_t		ms_overflow_pages;	/**< Number of overflow pages */
+	size_t		ms_entries;			/**< Number of data items */
+} MDB_stat;
+
+/** @brief Information about the environment */
+typedef struct MDB_envinfo {
+	void	*me_mapaddr;			/**< Address of map, if fixed */
+	size_t	me_mapsize;				/**< Size of the data memory map */
+	size_t	me_last_pgno;			/**< ID of the last used page */
+	size_t	me_last_txnid;			/**< ID of the last committed transaction */
+	unsigned int me_maxreaders;		/**< max reader slots in the environment */
+	unsigned int me_numreaders;		/**< max reader slots used in the environment */
+} MDB_envinfo;
+
+	/** @brief Return the LMDB library version information.
+	 *
+	 * @param[out] major if non-NULL, the library major version number is copied here
+	 * @param[out] minor if non-NULL, the library minor version number is copied here
+	 * @param[out] patch if non-NULL, the library patch version number is copied here
+	 * @retval "version string" The library version as a string
+	 */
+char *mdb_version(int *major, int *minor, int *patch);
+
+	/** @brief Return a string describing a given error code.
+	 *
+	 * This function is a superset of the ANSI C X3.159-1989 (ANSI C) strerror(3)
+	 * function. If the error code is greater than or equal to 0, then the string
+	 * returned by the system function strerror(3) is returned. If the error code
+	 * is less than 0, an error string corresponding to the LMDB library error is
+	 * returned. See @ref errors for a list of LMDB-specific error codes.
+	 * @param[in] err The error code
+	 * @retval "error message" The description of the error
+	 */
+char *mdb_strerror(int err);
+
+	/** @brief Create an LMDB environment handle.
+	 *
+	 * This function allocates memory for a #MDB_env structure. To release
+	 * the allocated memory and discard the handle, call #mdb_env_close().
+	 * Before the handle may be used, it must be opened using #mdb_env_open().
+	 * Various other options may also need to be set before opening the handle,
+	 * e.g. #mdb_env_set_mapsize(), #mdb_env_set_maxreaders(), #mdb_env_set_maxdbs(),
+	 * depending on usage requirements.
+	 * @param[out] env The address where the new handle will be stored
+	 * @return A non-zero error value on failure and 0 on success.
+	 */
+int  mdb_env_create(MDB_env **env);
+
+	/** @brief Open an environment handle.
+	 *
+	 * If this function fails, #mdb_env_close() must be called to discard the #MDB_env handle.
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[in] path The directory in which the database files reside. This
+	 * directory must already exist and be writable.
+	 * @param[in] flags Special options for this environment. This parameter
+	 * must be set to 0 or by bitwise OR'ing together one or more of the
+	 * values described here.
+	 * Flags set by mdb_env_set_flags() are also used.
+	 * <ul>
+	 *	<li>#MDB_FIXEDMAP
+	 *      use a fixed address for the mmap region. This flag must be specified
+	 *      when creating the environment, and is stored persistently in the environment.
+	 *		If successful, the memory map will always reside at the same virtual address
+	 *		and pointers used to reference data items in the database will be constant
+	 *		across multiple invocations. This option may not always work, depending on
+	 *		how the operating system has allocated memory to shared libraries and other uses.
+	 *		The feature is highly experimental.
+	 *	<li>#MDB_NOSUBDIR
+	 *		By default, LMDB creates its environment in a directory whose
+	 *		pathname is given in \b path, and creates its data and lock files
+	 *		under that directory. With this option, \b path is used as-is for
+	 *		the database main data file. The database lock file is the \b path
+	 *		with "-lock" appended.
+	 *	<li>#MDB_RDONLY
+	 *		Open the environment in read-only mode. No write operations will be
+	 *		allowed. LMDB will still modify the lock file - except on read-only
+	 *		filesystems, where LMDB does not use locks.
+	 *	<li>#MDB_WRITEMAP
+	 *		Use a writeable memory map unless MDB_RDONLY is set. This is faster
+	 *		and uses fewer mallocs, but loses protection from application bugs
+	 *		like wild pointer writes and other bad updates into the database.
+	 *		Incompatible with nested transactions.
+	 *		Processes with and without MDB_WRITEMAP on the same environment do
+	 *		not cooperate well.
+	 *	<li>#MDB_NOMETASYNC
+	 *		Flush system buffers to disk only once per transaction, omit the
+	 *		metadata flush. Defer that until the system flushes files to disk,
+	 *		or next non-MDB_RDONLY commit or #mdb_env_sync(). This optimization
+	 *		maintains database integrity, but a system crash may undo the last
+	 *		committed transaction. I.e. it preserves the ACI (atomicity,
+	 *		consistency, isolation) but not D (durability) database property.
+	 *		This flag may be changed at any time using #mdb_env_set_flags().
+	 *	<li>#MDB_NOSYNC
+	 *		Don't flush system buffers to disk when committing a transaction.
+	 *		This optimization means a system crash can corrupt the database or
+	 *		lose the last transactions if buffers are not yet flushed to disk.
+	 *		The risk is governed by how often the system flushes dirty buffers
+	 *		to disk and how often #mdb_env_sync() is called.  However, if the
+	 *		filesystem preserves write order and the #MDB_WRITEMAP flag is not
+	 *		used, transactions exhibit ACI (atomicity, consistency, isolation)
+	 *		properties and only lose D (durability).  I.e. database integrity
+	 *		is maintained, but a system crash may undo the final transactions.
+	 *		Note that (#MDB_NOSYNC | #MDB_WRITEMAP) leaves the system with no
+	 *		hint for when to write transactions to disk, unless #mdb_env_sync()
+	 *		is called. (#MDB_MAPASYNC | #MDB_WRITEMAP) may be preferable.
+	 *		This flag may be changed at any time using #mdb_env_set_flags().
+	 *	<li>#MDB_MAPASYNC
+	 *		When using #MDB_WRITEMAP, use asynchronous flushes to disk.
+	 *		As with #MDB_NOSYNC, a system crash can then corrupt the
+	 *		database or lose the last transactions. Calling #mdb_env_sync()
+	 *		ensures on-disk database integrity until next commit.
+	 *		This flag may be changed at any time using #mdb_env_set_flags().
+	 *	<li>#MDB_NOTLS
+	 *		Don't use Thread-Local Storage. Tie reader locktable slots to
+	 *		#MDB_txn objects instead of to threads. I.e. #mdb_txn_reset() keeps
+	 *		the slot reseved for the #MDB_txn object. A thread may use parallel
+	 *		read-only transactions. A read-only transaction may span threads if
+	 *		the user synchronizes its use. Applications that multiplex many
+	 *		user threads over individual OS threads need this option. Such an
+	 *		application must also serialize the write transactions in an OS
+	 *		thread, since LMDB's write locking is unaware of the user threads.
+	 *	<li>#MDB_NOLOCK
+	 *		Don't do any locking. If concurrent access is anticipated, the
+	 *		caller must manage all concurrency itself. For proper operation
+	 *		the caller must enforce single-writer semantics, and must ensure
+	 *		that no readers are using old transactions while a writer is
+	 *		active. The simplest approach is to use an exclusive lock so that
+	 *		no readers may be active at all when a writer begins.
+	 *	<li>#MDB_NORDAHEAD
+	 *		Turn off readahead. Most operating systems perform readahead on
+	 *		read requests by default. This option turns it off if the OS
+	 *		supports it. Turning it off may help random read performance
+	 *		when the DB is larger than RAM and system RAM is full.
+	 *		The option is not implemented on Windows.
+	 *	<li>#MDB_NOMEMINIT
+	 *		Don't initialize malloc'd memory before writing to unused spaces
+	 *		in the data file. By default, memory for pages written to the data
+	 *		file is obtained using malloc. While these pages may be reused in
+	 *		subsequent transactions, freshly malloc'd pages will be initialized
+	 *		to zeroes before use. This avoids persisting leftover data from other
+	 *		code (that used the heap and subsequently freed the memory) into the
+	 *		data file. Note that many other system libraries may allocate
+	 *		and free memory from the heap for arbitrary uses. E.g., stdio may
+	 *		use the heap for file I/O buffers. This initialization step has a
+	 *		modest performance cost so some applications may want to disable
+	 *		it using this flag. This option can be a problem for applications
+	 *		which handle sensitive data like passwords, and it makes memory
+	 *		checkers like Valgrind noisy. This flag is not needed with #MDB_WRITEMAP,
+	 *		which writes directly to the mmap instead of using malloc for pages. The
+	 *		initialization is also skipped if #MDB_RESERVE is used; the
+	 *		caller is expected to overwrite all of the memory that was
+	 *		reserved in that case.
+	 *		This flag may be changed at any time using #mdb_env_set_flags().
+	 * </ul>
+	 * @param[in] mode The UNIX permissions to set on created files. This parameter
+	 * is ignored on Windows.
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>#MDB_VERSION_MISMATCH - the version of the LMDB library doesn't match the
+	 *	version that created the database environment.
+	 *	<li>#MDB_INVALID - the environment file headers are corrupted.
+	 *	<li>ENOENT - the directory specified by the path parameter doesn't exist.
+	 *	<li>EACCES - the user didn't have permission to access the environment files.
+	 *	<li>EAGAIN - the environment was locked by another process.
+	 * </ul>
+	 */
+int  mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode);
+
+	/** @brief Copy an LMDB environment to the specified path.
+	 *
+	 * This function may be used to make a backup of an existing environment.
+	 * No lockfile is created, since it gets recreated at need.
+	 * @note This call can trigger significant file size growth if run in
+	 * parallel with write transactions, because it employs a read-only
+	 * transaction. See long-lived transactions under @ref caveats_sec.
+	 * @param[in] env An environment handle returned by #mdb_env_create(). It
+	 * must have already been opened successfully.
+	 * @param[in] path The directory in which the copy will reside. This
+	 * directory must already exist and be writable but must otherwise be
+	 * empty.
+	 * @return A non-zero error value on failure and 0 on success.
+	 */
+int  mdb_env_copy(MDB_env *env, const char *path);
+
+	/** @brief Copy an LMDB environment to the specified file descriptor.
+	 *
+	 * This function may be used to make a backup of an existing environment.
+	 * No lockfile is created, since it gets recreated at need.
+	 * @note This call can trigger significant file size growth if run in
+	 * parallel with write transactions, because it employs a read-only
+	 * transaction. See long-lived transactions under @ref caveats_sec.
+	 * @param[in] env An environment handle returned by #mdb_env_create(). It
+	 * must have already been opened successfully.
+	 * @param[in] fd The filedescriptor to write the copy to. It must
+	 * have already been opened for Write access.
+	 * @return A non-zero error value on failure and 0 on success.
+	 */
+int  mdb_env_copyfd(MDB_env *env, mdb_filehandle_t fd);
+
+	/** @brief Copy an LMDB environment to the specified path, with options.
+	 *
+	 * This function may be used to make a backup of an existing environment.
+	 * No lockfile is created, since it gets recreated at need.
+	 * @note This call can trigger significant file size growth if run in
+	 * parallel with write transactions, because it employs a read-only
+	 * transaction. See long-lived transactions under @ref caveats_sec.
+	 * @param[in] env An environment handle returned by #mdb_env_create(). It
+	 * must have already been opened successfully.
+	 * @param[in] path The directory in which the copy will reside. This
+	 * directory must already exist and be writable but must otherwise be
+	 * empty.
+	 * @param[in] flags Special options for this operation. This parameter
+	 * must be set to 0 or by bitwise OR'ing together one or more of the
+	 * values described here.
+	 * <ul>
+	 *	<li>#MDB_CP_COMPACT - Perform compaction while copying: omit free
+	 *		pages and sequentially renumber all pages in output. This option
+	 *		consumes more CPU and runs more slowly than the default.
+	 * </ul>
+	 * @return A non-zero error value on failure and 0 on success.
+	 */
+int  mdb_env_copy2(MDB_env *env, const char *path, unsigned int flags);
+
+	/** @brief Copy an LMDB environment to the specified file descriptor,
+	 *	with options.
+	 *
+	 * This function may be used to make a backup of an existing environment.
+	 * No lockfile is created, since it gets recreated at need. See
+	 * #mdb_env_copy2() for further details.
+	 * @note This call can trigger significant file size growth if run in
+	 * parallel with write transactions, because it employs a read-only
+	 * transaction. See long-lived transactions under @ref caveats_sec.
+	 * @param[in] env An environment handle returned by #mdb_env_create(). It
+	 * must have already been opened successfully.
+	 * @param[in] fd The filedescriptor to write the copy to. It must
+	 * have already been opened for Write access.
+	 * @param[in] flags Special options for this operation.
+	 * See #mdb_env_copy2() for options.
+	 * @return A non-zero error value on failure and 0 on success.
+	 */
+int  mdb_env_copyfd2(MDB_env *env, mdb_filehandle_t fd, unsigned int flags);
+
+	/** @brief Return statistics about the LMDB environment.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[out] stat The address of an #MDB_stat structure
+	 * 	where the statistics will be copied
+	 */
+int  mdb_env_stat(MDB_env *env, MDB_stat *stat);
+
+	/** @brief Return information about the LMDB environment.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[out] stat The address of an #MDB_envinfo structure
+	 * 	where the information will be copied
+	 */
+int  mdb_env_info(MDB_env *env, MDB_envinfo *stat);
+
+	/** @brief Flush the data buffers to disk.
+	 *
+	 * Data is always written to disk when #mdb_txn_commit() is called,
+	 * but the operating system may keep it buffered. LMDB always flushes
+	 * the OS buffers upon commit as well, unless the environment was
+	 * opened with #MDB_NOSYNC or in part #MDB_NOMETASYNC.
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[in] force If non-zero, force a synchronous flush.  Otherwise
+	 *  if the environment has the #MDB_NOSYNC flag set the flushes
+	 *	will be omitted, and with #MDB_MAPASYNC they will be asynchronous.
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 *	<li>EIO - an error occurred during synchronization.
+	 * </ul>
+	 */
+int  mdb_env_sync(MDB_env *env, int force);
+
+	/** @brief Close the environment and release the memory map.
+	 *
+	 * Only a single thread may call this function. All transactions, databases,
+	 * and cursors must already be closed before calling this function. Attempts to
+	 * use any such handles after calling this function will cause a SIGSEGV.
+	 * The environment handle will be freed and must not be used again after this call.
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 */
+void mdb_env_close(MDB_env *env);
+
+	/** @brief Set environment flags.
+	 *
+	 * This may be used to set some flags in addition to those from
+	 * #mdb_env_open(), or to unset these flags.  If several threads
+	 * change the flags at the same time, the result is undefined.
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[in] flags The flags to change, bitwise OR'ed together
+	 * @param[in] onoff A non-zero value sets the flags, zero clears them.
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_env_set_flags(MDB_env *env, unsigned int flags, int onoff);
+
+	/** @brief Get environment flags.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[out] flags The address of an integer to store the flags
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_env_get_flags(MDB_env *env, unsigned int *flags);
+
+	/** @brief Return the path that was used in #mdb_env_open().
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[out] path Address of a string pointer to contain the path. This
+	 * is the actual string in the environment, not a copy. It should not be
+	 * altered in any way.
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_env_get_path(MDB_env *env, const char **path);
+
+	/** @brief Return the filedescriptor for the given environment.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[out] fd Address of a mdb_filehandle_t to contain the descriptor.
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_env_get_fd(MDB_env *env, mdb_filehandle_t *fd);
+
+	/** @brief Set the size of the memory map to use for this environment.
+	 *
+	 * The size should be a multiple of the OS page size. The default is
+	 * 10485760 bytes. The size of the memory map is also the maximum size
+	 * of the database. The value should be chosen as large as possible,
+	 * to accommodate future growth of the database.
+	 * This function should be called after #mdb_env_create() and before #mdb_env_open().
+	 * It may be called at later times if no transactions are active in
+	 * this process. Note that the library does not check for this condition,
+	 * the caller must ensure it explicitly.
+	 *
+	 * The new size takes effect immediately for the current process but
+	 * will not be persisted to any others until a write transaction has been
+	 * committed by the current process. Also, only mapsize increases are
+	 * persisted into the environment.
+	 *
+	 * If the mapsize is increased by another process, and data has grown
+	 * beyond the range of the current mapsize, #mdb_txn_begin() will
+	 * return #MDB_MAP_RESIZED. This function may be called with a size
+	 * of zero to adopt the new size.
+	 *
+	 * Any attempt to set a size smaller than the space already consumed
+	 * by the environment will be silently changed to the current size of the used space.
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[in] size The size in bytes
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified, or the environment has
+	 *   	an active write transaction.
+	 * </ul>
+	 */
+int  mdb_env_set_mapsize(MDB_env *env, size_t size);
+
+	/** @brief Set the maximum number of threads/reader slots for the environment.
+	 *
+	 * This defines the number of slots in the lock table that is used to track readers in the
+	 * the environment. The default is 126.
+	 * Starting a read-only transaction normally ties a lock table slot to the
+	 * current thread until the environment closes or the thread exits. If
+	 * MDB_NOTLS is in use, #mdb_txn_begin() instead ties the slot to the
+	 * MDB_txn object until it or the #MDB_env object is destroyed.
+	 * This function may only be called after #mdb_env_create() and before #mdb_env_open().
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[in] readers The maximum number of reader lock table slots
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified, or the environment is already open.
+	 * </ul>
+	 */
+int  mdb_env_set_maxreaders(MDB_env *env, unsigned int readers);
+
+	/** @brief Get the maximum number of threads/reader slots for the environment.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[out] readers Address of an integer to store the number of readers
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers);
+
+	/** @brief Set the maximum number of named databases for the environment.
+	 *
+	 * This function is only needed if multiple databases will be used in the
+	 * environment. Simpler applications that use the environment as a single
+	 * unnamed database can ignore this option.
+	 * This function may only be called after #mdb_env_create() and before #mdb_env_open().
+	 *
+	 * Currently a moderate number of slots are cheap but a huge number gets
+	 * expensive: 7-120 words per transaction, and every #mdb_dbi_open()
+	 * does a linear search of the opened slots.
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[in] dbs The maximum number of databases
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified, or the environment is already open.
+	 * </ul>
+	 */
+int  mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs);
+
+	/** @brief Get the maximum size of keys and #MDB_DUPSORT data we can write.
+	 *
+	 * Depends on the compile-time constant #MDB_MAXKEYSIZE. Default 511.
+	 * See @ref MDB_val.
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @return The maximum size of a key we can write
+	 */
+int  mdb_env_get_maxkeysize(MDB_env *env);
+
+	/** @brief Set application information associated with the #MDB_env.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[in] ctx An arbitrary pointer for whatever the application needs.
+	 * @return A non-zero error value on failure and 0 on success.
+	 */
+int  mdb_env_set_userctx(MDB_env *env, void *ctx);
+
+	/** @brief Get the application information associated with the #MDB_env.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @return The pointer set by #mdb_env_set_userctx().
+	 */
+void *mdb_env_get_userctx(MDB_env *env);
+
+	/** @brief A callback function for most LMDB assert() failures,
+	 * called before printing the message and aborting.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create().
+	 * @param[in] msg The assertion message, not including newline.
+	 */
+typedef void MDB_assert_func(MDB_env *env, const char *msg);
+
+	/** Set or reset the assert() callback of the environment.
+	 * Disabled if liblmdb is buillt with NDEBUG.
+	 * @note This hack should become obsolete as lmdb's error handling matures.
+	 * @param[in] env An environment handle returned by #mdb_env_create().
+	 * @param[in] func An #MDB_assert_func function, or 0.
+	 * @return A non-zero error value on failure and 0 on success.
+	 */
+int  mdb_env_set_assert(MDB_env *env, MDB_assert_func *func);
+
+	/** @brief Create a transaction for use with the environment.
+	 *
+	 * The transaction handle may be discarded using #mdb_txn_abort() or #mdb_txn_commit().
+	 * @note A transaction and its cursors must only be used by a single
+	 * thread, and a thread may only have a single transaction at a time.
+	 * If #MDB_NOTLS is in use, this does not apply to read-only transactions.
+	 * @note Cursors may not span transactions.
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[in] parent If this parameter is non-NULL, the new transaction
+	 * will be a nested transaction, with the transaction indicated by \b parent
+	 * as its parent. Transactions may be nested to any level. A parent
+	 * transaction and its cursors may not issue any other operations than
+	 * mdb_txn_commit and mdb_txn_abort while it has active child transactions.
+	 * @param[in] flags Special options for this transaction. This parameter
+	 * must be set to 0 or by bitwise OR'ing together one or more of the
+	 * values described here.
+	 * <ul>
+	 *	<li>#MDB_RDONLY
+	 *		This transaction will not perform any write operations.
+	 * </ul>
+	 * @param[out] txn Address where the new #MDB_txn handle will be stored
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>#MDB_PANIC - a fatal error occurred earlier and the environment
+	 *		must be shut down.
+	 *	<li>#MDB_MAP_RESIZED - another process wrote data beyond this MDB_env's
+	 *		mapsize and this environment's map must be resized as well.
+	 *		See #mdb_env_set_mapsize().
+	 *	<li>#MDB_READERS_FULL - a read-only transaction was requested and
+	 *		the reader lock table is full. See #mdb_env_set_maxreaders().
+	 *	<li>ENOMEM - out of memory.
+	 * </ul>
+	 */
+int  mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **txn);
+
+	/** @brief Returns the transaction's #MDB_env
+	 *
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 */
+MDB_env *mdb_txn_env(MDB_txn *txn);
+
+	/** @brief Commit all the operations of a transaction into the database.
+	 *
+	 * The transaction handle is freed. It and its cursors must not be used
+	 * again after this call, except with #mdb_cursor_renew().
+	 * @note Earlier documentation incorrectly said all cursors would be freed.
+	 * Only write-transactions free cursors.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 *	<li>ENOSPC - no more disk space.
+	 *	<li>EIO - a low-level I/O error occurred while writing.
+	 *	<li>ENOMEM - out of memory.
+	 * </ul>
+	 */
+int  mdb_txn_commit(MDB_txn *txn);
+
+	/** @brief Abandon all the operations of the transaction instead of saving them.
+	 *
+	 * The transaction handle is freed. It and its cursors must not be used
+	 * again after this call, except with #mdb_cursor_renew().
+	 * @note Earlier documentation incorrectly said all cursors would be freed.
+	 * Only write-transactions free cursors.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 */
+void mdb_txn_abort(MDB_txn *txn);
+
+	/** @brief Reset a read-only transaction.
+	 *
+	 * Abort the transaction like #mdb_txn_abort(), but keep the transaction
+	 * handle. #mdb_txn_renew() may reuse the handle. This saves allocation
+	 * overhead if the process will start a new read-only transaction soon,
+	 * and also locking overhead if #MDB_NOTLS is in use. The reader table
+	 * lock is released, but the table slot stays tied to its thread or
+	 * #MDB_txn. Use mdb_txn_abort() to discard a reset handle, and to free
+	 * its lock table slot if MDB_NOTLS is in use.
+	 * Cursors opened within the transaction must not be used
+	 * again after this call, except with #mdb_cursor_renew().
+	 * Reader locks generally don't interfere with writers, but they keep old
+	 * versions of database pages allocated. Thus they prevent the old pages
+	 * from being reused when writers commit new data, and so under heavy load
+	 * the database size may grow much more rapidly than otherwise.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 */
+void mdb_txn_reset(MDB_txn *txn);
+
+	/** @brief Renew a read-only transaction.
+	 *
+	 * This acquires a new reader lock for a transaction handle that had been
+	 * released by #mdb_txn_reset(). It must be called before a reset transaction
+	 * may be used again.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>#MDB_PANIC - a fatal error occurred earlier and the environment
+	 *		must be shut down.
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_txn_renew(MDB_txn *txn);
+
+/** Compat with version <= 0.9.4, avoid clash with libmdb from MDB Tools project */
+#define mdb_open(txn,name,flags,dbi)	mdb_dbi_open(txn,name,flags,dbi)
+/** Compat with version <= 0.9.4, avoid clash with libmdb from MDB Tools project */
+#define mdb_close(env,dbi)				mdb_dbi_close(env,dbi)
+
+	/** @brief Open a database in the environment.
+	 *
+	 * A database handle denotes the name and parameters of a database,
+	 * independently of whether such a database exists.
+	 * The database handle may be discarded by calling #mdb_dbi_close().
+	 * The old database handle is returned if the database was already open.
+	 * The handle may only be closed once.
+	 * The database handle will be private to the current transaction until
+	 * the transaction is successfully committed. If the transaction is
+	 * aborted the handle will be closed automatically.
+	 * After a successful commit the
+	 * handle will reside in the shared environment, and may be used
+	 * by other transactions. This function must not be called from
+	 * multiple concurrent transactions. A transaction that uses this function
+	 * must finish (either commit or abort) before any other transaction may
+	 * use this function.
+	 *
+	 * To use named databases (with name != NULL), #mdb_env_set_maxdbs()
+	 * must be called before opening the environment.  Database names
+	 * are kept as keys in the unnamed database.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] name The name of the database to open. If only a single
+	 * 	database is needed in the environment, this value may be NULL.
+	 * @param[in] flags Special options for this database. This parameter
+	 * must be set to 0 or by bitwise OR'ing together one or more of the
+	 * values described here.
+	 * <ul>
+	 *	<li>#MDB_REVERSEKEY
+	 *		Keys are strings to be compared in reverse order, from the end
+	 *		of the strings to the beginning. By default, Keys are treated as strings and
+	 *		compared from beginning to end.
+	 *	<li>#MDB_DUPSORT
+	 *		Duplicate keys may be used in the database. (Or, from another perspective,
+	 *		keys may have multiple data items, stored in sorted order.) By default
+	 *		keys must be unique and may have only a single data item.
+	 *	<li>#MDB_INTEGERKEY
+	 *		Keys are binary integers in native byte order. Setting this option
+	 *		requires all keys to be the same size, typically sizeof(int)
+	 *		or sizeof(size_t).
+	 *	<li>#MDB_DUPFIXED
+	 *		This flag may only be used in combination with #MDB_DUPSORT. This option
+	 *		tells the library that the data items for this database are all the same
+	 *		size, which allows further optimizations in storage and retrieval. When
+	 *		all data items are the same size, the #MDB_GET_MULTIPLE and #MDB_NEXT_MULTIPLE
+	 *		cursor operations may be used to retrieve multiple items at once.
+	 *	<li>#MDB_INTEGERDUP
+	 *		This option specifies that duplicate data items are also integers, and
+	 *		should be sorted as such.
+	 *	<li>#MDB_REVERSEDUP
+	 *		This option specifies that duplicate data items should be compared as
+	 *		strings in reverse order.
+	 *	<li>#MDB_CREATE
+	 *		Create the named database if it doesn't exist. This option is not
+	 *		allowed in a read-only transaction or a read-only environment.
+	 * </ul>
+	 * @param[out] dbi Address where the new #MDB_dbi handle will be stored
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>#MDB_NOTFOUND - the specified database doesn't exist in the environment
+	 *		and #MDB_CREATE was not specified.
+	 *	<li>#MDB_DBS_FULL - too many databases have been opened. See #mdb_env_set_maxdbs().
+	 * </ul>
+	 */
+int  mdb_dbi_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi);
+
+	/** @brief Retrieve statistics for a database.
+	 *
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[out] stat The address of an #MDB_stat structure
+	 * 	where the statistics will be copied
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *stat);
+
+	/** @brief Retrieve the DB flags for a database handle.
+	 *
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[out] flags Address where the flags will be returned.
+	 * @return A non-zero error value on failure and 0 on success.
+	 */
+int mdb_dbi_flags(MDB_txn *txn, MDB_dbi dbi, unsigned int *flags);
+
+	/** @brief Close a database handle. Normally unnecessary. Use with care:
+	 *
+	 * This call is not mutex protected. Handles should only be closed by
+	 * a single thread, and only if no other threads are going to reference
+	 * the database handle or one of its cursors any further. Do not close
+	 * a handle if an existing transaction has modified its database.
+	 * Doing so can cause misbehavior from database corruption to errors
+	 * like MDB_BAD_VALSIZE (since the DB name is gone).
+	 *
+	 * Closing a database handle is not necessary, but lets #mdb_dbi_open()
+	 * reuse the handle value.  Usually it's better to set a bigger
+	 * #mdb_env_set_maxdbs(), unless that value would be large.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 */
+void mdb_dbi_close(MDB_env *env, MDB_dbi dbi);
+
+	/** @brief Empty or delete+close a database.
+	 *
+	 * See #mdb_dbi_close() for restrictions about closing the DB handle.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[in] del 0 to empty the DB, 1 to delete it from the
+	 * environment and close the DB handle.
+	 * @return A non-zero error value on failure and 0 on success.
+	 */
+int  mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del);
+
+	/** @brief Set a custom key comparison function for a database.
+	 *
+	 * The comparison function is called whenever it is necessary to compare a
+	 * key specified by the application with a key currently stored in the database.
+	 * If no comparison function is specified, and no special key flags were specified
+	 * with #mdb_dbi_open(), the keys are compared lexically, with shorter keys collating
+	 * before longer keys.
+	 * @warning This function must be called before any data access functions are used,
+	 * otherwise data corruption may occur. The same comparison function must be used by every
+	 * program accessing the database, every time the database is used.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[in] cmp A #MDB_cmp_func function
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp);
+
+	/** @brief Set a custom data comparison function for a #MDB_DUPSORT database.
+	 *
+	 * This comparison function is called whenever it is necessary to compare a data
+	 * item specified by the application with a data item currently stored in the database.
+	 * This function only takes effect if the database was opened with the #MDB_DUPSORT
+	 * flag.
+	 * If no comparison function is specified, and no special key flags were specified
+	 * with #mdb_dbi_open(), the data items are compared lexically, with shorter items collating
+	 * before longer items.
+	 * @warning This function must be called before any data access functions are used,
+	 * otherwise data corruption may occur. The same comparison function must be used by every
+	 * program accessing the database, every time the database is used.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[in] cmp A #MDB_cmp_func function
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_set_dupsort(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp);
+
+	/** @brief Set a relocation function for a #MDB_FIXEDMAP database.
+	 *
+	 * @todo The relocation function is called whenever it is necessary to move the data
+	 * of an item to a different position in the database (e.g. through tree
+	 * balancing operations, shifts as a result of adds or deletes, etc.). It is
+	 * intended to allow address/position-dependent data items to be stored in
+	 * a database in an environment opened with the #MDB_FIXEDMAP option.
+	 * Currently the relocation feature is unimplemented and setting
+	 * this function has no effect.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[in] rel A #MDB_rel_func function
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel);
+
+	/** @brief Set a context pointer for a #MDB_FIXEDMAP database's relocation function.
+	 *
+	 * See #mdb_set_relfunc and #MDB_rel_func for more details.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[in] ctx An arbitrary pointer for whatever the application needs.
+	 * It will be passed to the callback function set by #mdb_set_relfunc
+	 * as its \b relctx parameter whenever the callback is invoked.
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx);
+
+	/** @brief Get items from a database.
+	 *
+	 * This function retrieves key/data pairs from the database. The address
+	 * and length of the data associated with the specified \b key are returned
+	 * in the structure to which \b data refers.
+	 * If the database supports duplicate keys (#MDB_DUPSORT) then the
+	 * first data item for the key will be returned. Retrieval of other
+	 * items requires the use of #mdb_cursor_get().
+	 *
+	 * @note The memory pointed to by the returned values is owned by the
+	 * database. The caller need not dispose of the memory, and may not
+	 * modify it in any way. For values returned in a read-only transaction
+	 * any modification attempts will cause a SIGSEGV.
+	 * @note Values returned from the database are valid only until a
+	 * subsequent update operation, or the end of the transaction.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[in] key The key to search for in the database
+	 * @param[out] data The data corresponding to the key
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>#MDB_NOTFOUND - the key was not in the database.
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_get(MDB_txn *txn, MDB_dbi dbi, MDB_val *key, MDB_val *data);
+
+	/** @brief Store items into a database.
+	 *
+	 * This function stores key/data pairs in the database. The default behavior
+	 * is to enter the new key/data pair, replacing any previously existing key
+	 * if duplicates are disallowed, or adding a duplicate data item if
+	 * duplicates are allowed (#MDB_DUPSORT).
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[in] key The key to store in the database
+	 * @param[in,out] data The data to store
+	 * @param[in] flags Special options for this operation. This parameter
+	 * must be set to 0 or by bitwise OR'ing together one or more of the
+	 * values described here.
+	 * <ul>
+	 *	<li>#MDB_NODUPDATA - enter the new key/data pair only if it does not
+	 *		already appear in the database. This flag may only be specified
+	 *		if the database was opened with #MDB_DUPSORT. The function will
+	 *		return #MDB_KEYEXIST if the key/data pair already appears in the
+	 *		database.
+	 *	<li>#MDB_NOOVERWRITE - enter the new key/data pair only if the key
+	 *		does not already appear in the database. The function will return
+	 *		#MDB_KEYEXIST if the key already appears in the database, even if
+	 *		the database supports duplicates (#MDB_DUPSORT). The \b data
+	 *		parameter will be set to point to the existing item.
+	 *	<li>#MDB_RESERVE - reserve space for data of the given size, but
+	 *		don't copy the given data. Instead, return a pointer to the
+	 *		reserved space, which the caller can fill in later - before
+	 *		the next update operation or the transaction ends. This saves
+	 *		an extra memcpy if the data is being generated later.
+	 *		LMDB does nothing else with this memory, the caller is expected
+	 *		to modify all of the space requested.
+	 *	<li>#MDB_APPEND - append the given key/data pair to the end of the
+	 *		database. No key comparisons are performed. This option allows
+	 *		fast bulk loading when keys are already known to be in the
+	 *		correct order. Loading unsorted keys with this flag will cause
+	 *		data corruption.
+	 *	<li>#MDB_APPENDDUP - as above, but for sorted dup data.
+	 * </ul>
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>#MDB_MAP_FULL - the database is full, see #mdb_env_set_mapsize().
+	 *	<li>#MDB_TXN_FULL - the transaction has too many dirty pages.
+	 *	<li>EACCES - an attempt was made to write in a read-only transaction.
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_put(MDB_txn *txn, MDB_dbi dbi, MDB_val *key, MDB_val *data,
+			    unsigned int flags);
+
+	/** @brief Delete items from a database.
+	 *
+	 * This function removes key/data pairs from the database.
+	 * If the database does not support sorted duplicate data items
+	 * (#MDB_DUPSORT) the data parameter is ignored.
+	 * If the database supports sorted duplicates and the data parameter
+	 * is NULL, all of the duplicate data items for the key will be
+	 * deleted. Otherwise, if the data parameter is non-NULL
+	 * only the matching data item will be deleted.
+	 * This function will return #MDB_NOTFOUND if the specified key/data
+	 * pair is not in the database.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[in] key The key to delete from the database
+	 * @param[in] data The data to delete
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EACCES - an attempt was made to write in a read-only transaction.
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_del(MDB_txn *txn, MDB_dbi dbi, MDB_val *key, MDB_val *data);
+
+	/** @brief Create a cursor handle.
+	 *
+	 * A cursor is associated with a specific transaction and database.
+	 * A cursor cannot be used when its database handle is closed.  Nor
+	 * when its transaction has ended, except with #mdb_cursor_renew().
+	 * It can be discarded with #mdb_cursor_close().
+	 * A cursor in a write-transaction can be closed before its transaction
+	 * ends, and will otherwise be closed when its transaction ends.
+	 * A cursor in a read-only transaction must be closed explicitly, before
+	 * or after its transaction ends. It can be reused with
+	 * #mdb_cursor_renew() before finally closing it.
+	 * @note Earlier documentation said that cursors in every transaction
+	 * were closed when the transaction committed or aborted.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[out] cursor Address where the new #MDB_cursor handle will be stored
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **cursor);
+
+	/** @brief Close a cursor handle.
+	 *
+	 * The cursor handle will be freed and must not be used again after this call.
+	 * Its transaction must still be live if it is a write-transaction.
+	 * @param[in] cursor A cursor handle returned by #mdb_cursor_open()
+	 */
+void mdb_cursor_close(MDB_cursor *cursor);
+
+	/** @brief Renew a cursor handle.
+	 *
+	 * A cursor is associated with a specific transaction and database.
+	 * Cursors that are only used in read-only
+	 * transactions may be re-used, to avoid unnecessary malloc/free overhead.
+	 * The cursor may be associated with a new read-only transaction, and
+	 * referencing the same database handle as it was created with.
+	 * This may be done whether the previous transaction is live or dead.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] cursor A cursor handle returned by #mdb_cursor_open()
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_cursor_renew(MDB_txn *txn, MDB_cursor *cursor);
+
+	/** @brief Return the cursor's transaction handle.
+	 *
+	 * @param[in] cursor A cursor handle returned by #mdb_cursor_open()
+	 */
+MDB_txn *mdb_cursor_txn(MDB_cursor *cursor);
+
+	/** @brief Return the cursor's database handle.
+	 *
+	 * @param[in] cursor A cursor handle returned by #mdb_cursor_open()
+	 */
+MDB_dbi mdb_cursor_dbi(MDB_cursor *cursor);
+
+	/** @brief Retrieve by cursor.
+	 *
+	 * This function retrieves key/data pairs from the database. The address and length
+	 * of the key are returned in the object to which \b key refers (except for the
+	 * case of the #MDB_SET option, in which the \b key object is unchanged), and
+	 * the address and length of the data are returned in the object to which \b data
+	 * refers.
+	 * See #mdb_get() for restrictions on using the output values.
+	 * @param[in] cursor A cursor handle returned by #mdb_cursor_open()
+	 * @param[in,out] key The key for a retrieved item
+	 * @param[in,out] data The data of a retrieved item
+	 * @param[in] op A cursor operation #MDB_cursor_op
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>#MDB_NOTFOUND - no matching key found.
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_cursor_get(MDB_cursor *cursor, MDB_val *key, MDB_val *data,
+			    MDB_cursor_op op);
+
+	/** @brief Store by cursor.
+	 *
+	 * This function stores key/data pairs into the database.
+	 * The cursor is positioned at the new item, or on failure usually near it.
+	 * @note Earlier documentation incorrectly said errors would leave the
+	 * state of the cursor unchanged.
+	 * @param[in] cursor A cursor handle returned by #mdb_cursor_open()
+	 * @param[in] key The key operated on.
+	 * @param[in] data The data operated on.
+	 * @param[in] flags Options for this operation. This parameter
+	 * must be set to 0 or one of the values described here.
+	 * <ul>
+	 *	<li>#MDB_CURRENT - replace the item at the current cursor position.
+	 *		The \b key parameter must still be provided, and must match it.
+	 *		If using sorted duplicates (#MDB_DUPSORT) the data item must still
+	 *		sort into the same place. This is intended to be used when the
+	 *		new data is the same size as the old. Otherwise it will simply
+	 *		perform a delete of the old record followed by an insert.
+	 *	<li>#MDB_NODUPDATA - enter the new key/data pair only if it does not
+	 *		already appear in the database. This flag may only be specified
+	 *		if the database was opened with #MDB_DUPSORT. The function will
+	 *		return #MDB_KEYEXIST if the key/data pair already appears in the
+	 *		database.
+	 *	<li>#MDB_NOOVERWRITE - enter the new key/data pair only if the key
+	 *		does not already appear in the database. The function will return
+	 *		#MDB_KEYEXIST if the key already appears in the database, even if
+	 *		the database supports duplicates (#MDB_DUPSORT).
+	 *	<li>#MDB_RESERVE - reserve space for data of the given size, but
+	 *		don't copy the given data. Instead, return a pointer to the
+	 *		reserved space, which the caller can fill in later. This saves
+	 *		an extra memcpy if the data is being generated later.
+	 *	<li>#MDB_APPEND - append the given key/data pair to the end of the
+	 *		database. No key comparisons are performed. This option allows
+	 *		fast bulk loading when keys are already known to be in the
+	 *		correct order. Loading unsorted keys with this flag will cause
+	 *		data corruption.
+	 *	<li>#MDB_APPENDDUP - as above, but for sorted dup data.
+	 *	<li>#MDB_MULTIPLE - store multiple contiguous data elements in a
+	 *		single request. This flag may only be specified if the database
+	 *		was opened with #MDB_DUPFIXED. The \b data argument must be an
+	 *		array of two MDB_vals. The mv_size of the first MDB_val must be
+	 *		the size of a single data element. The mv_data of the first MDB_val
+	 *		must point to the beginning of the array of contiguous data elements.
+	 *		The mv_size of the second MDB_val must be the count of the number
+	 *		of data elements to store. On return this field will be set to
+	 *		the count of the number of elements actually written. The mv_data
+	 *		of the second MDB_val is unused.
+	 * </ul>
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>#MDB_MAP_FULL - the database is full, see #mdb_env_set_mapsize().
+	 *	<li>#MDB_TXN_FULL - the transaction has too many dirty pages.
+	 *	<li>EACCES - an attempt was made to modify a read-only database.
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_cursor_put(MDB_cursor *cursor, MDB_val *key, MDB_val *data,
+				unsigned int flags);
+
+	/** @brief Delete current key/data pair
+	 *
+	 * This function deletes the key/data pair to which the cursor refers.
+	 * @param[in] cursor A cursor handle returned by #mdb_cursor_open()
+	 * @param[in] flags Options for this operation. This parameter
+	 * must be set to 0 or one of the values described here.
+	 * <ul>
+	 *	<li>#MDB_NODUPDATA - delete all of the data items for the current key.
+	 *		This flag may only be specified if the database was opened with #MDB_DUPSORT.
+	 * </ul>
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EACCES - an attempt was made to modify a read-only database.
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_cursor_del(MDB_cursor *cursor, unsigned int flags);
+
+	/** @brief Return count of duplicates for current key.
+	 *
+	 * This call is only valid on databases that support sorted duplicate
+	 * data items #MDB_DUPSORT.
+	 * @param[in] cursor A cursor handle returned by #mdb_cursor_open()
+	 * @param[out] countp Address where the count will be stored
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - cursor is not initialized, or an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_cursor_count(MDB_cursor *cursor, size_t *countp);
+
+	/** @brief Compare two data items according to a particular database.
+	 *
+	 * This returns a comparison as if the two data items were keys in the
+	 * specified database.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[in] a The first item to compare
+	 * @param[in] b The second item to compare
+	 * @return < 0 if a < b, 0 if a == b, > 0 if a > b
+	 */
+int  mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b);
+
+	/** @brief Compare two data items according to a particular database.
+	 *
+	 * This returns a comparison as if the two items were data items of
+	 * the specified database. The database must have the #MDB_DUPSORT flag.
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @param[in] dbi A database handle returned by #mdb_dbi_open()
+	 * @param[in] a The first item to compare
+	 * @param[in] b The second item to compare
+	 * @return < 0 if a < b, 0 if a == b, > 0 if a > b
+	 */
+int  mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b);
+
+	/** @brief A callback function used to print a message from the library.
+	 *
+	 * @param[in] msg The string to be printed.
+	 * @param[in] ctx An arbitrary context pointer for the callback.
+	 * @return < 0 on failure, >= 0 on success.
+	 */
+typedef int (MDB_msg_func)(const char *msg, void *ctx);
+
+	/** @brief Dump the entries in the reader lock table.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[in] func A #MDB_msg_func function
+	 * @param[in] ctx Anything the message function needs
+	 * @return < 0 on failure, >= 0 on success.
+	 */
+int	mdb_reader_list(MDB_env *env, MDB_msg_func *func, void *ctx);
+
+	/** @brief Check for stale entries in the reader lock table.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[out] dead Number of stale slots that were cleared
+	 * @return 0 on success, non-zero on failure.
+	 */
+int	mdb_reader_check(MDB_env *env, int *dead);
+/**	@} */
+
+#ifdef __cplusplus
+}
+#endif
+/** @page tools LMDB Command Line Tools
+	The following describes the command line tools that are available for LMDB.
+	\li \ref mdb_copy_1
+	\li \ref mdb_dump_1
+	\li \ref mdb_load_1
+	\li \ref mdb_stat_1
+*/
+
+#endif /* _LMDB_H_ */
diff --git a/external/db_drivers/liblmdb32/mdb.c b/external/db_drivers/liblmdb32/mdb.c
new file mode 100644
index 000000000..63fece3d7
--- /dev/null
+++ b/external/db_drivers/liblmdb32/mdb.c
@@ -0,0 +1,9572 @@
+/** @file mdb.c
+ *	@brief Lightning memory-mapped database library
+ *
+ *	A Btree-based database management library modeled loosely on the
+ *	BerkeleyDB API, but much simplified.
+ */
+/*
+ * Copyright 2011-2014 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ *
+ * This code is derived from btree.c written by Martin Hedenfalk.
+ *
+ * Copyright (c) 2009, 2010 Martin Hedenfalk <martin@bzero.se>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#endif
+#ifdef _WIN32
+#include <malloc.h>
+#include <windows.h>
+/** getpid() returns int; MinGW defines pid_t but MinGW64 typedefs it
+ *  as int64 which is wrong. MSVC doesn't define it at all, so just
+ *  don't use it.
+ */
+#define MDB_PID_T	int
+#define MDB_THR_T	DWORD
+#include <sys/types.h>
+#include <sys/stat.h>
+#ifdef __GNUC__
+# include <sys/param.h>
+#else
+# define LITTLE_ENDIAN	1234
+# define BIG_ENDIAN	4321
+# define BYTE_ORDER	LITTLE_ENDIAN
+# ifndef SSIZE_MAX
+#  define SSIZE_MAX	INT_MAX
+# endif
+#endif
+#else
+#include <sys/types.h>
+#include <sys/stat.h>
+#define MDB_PID_T	pid_t
+#define MDB_THR_T	pthread_t
+#include <sys/param.h>
+#include <sys/uio.h>
+#include <sys/mman.h>
+#ifdef HAVE_SYS_FILE_H
+#include <sys/file.h>
+#endif
+#include <fcntl.h>
+#endif
+
+#if defined(__mips) && defined(__linux)
+/* MIPS has cache coherency issues, requires explicit cache control */
+#include <asm/cachectl.h>
+extern int cacheflush(char *addr, int nbytes, int cache);
+#define CACHEFLUSH(addr, bytes, cache)	cacheflush(addr, bytes, cache)
+#else
+#define CACHEFLUSH(addr, bytes, cache)
+#endif
+
+
+#include <errno.h>
+#include <limits.h>
+#include <stddef.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#if defined(__sun) || defined(ANDROID)
+/* Most platforms have posix_memalign, older may only have memalign */
+#define HAVE_MEMALIGN	1
+#include <malloc.h>
+#endif
+
+#if !(defined(BYTE_ORDER) || defined(__BYTE_ORDER))
+#include <netinet/in.h>
+#include <resolv.h>	/* defines BYTE_ORDER on HPUX and Solaris */
+#endif
+
+#if defined(__APPLE__) || defined (BSD)
+# define MDB_USE_POSIX_SEM	1
+# define MDB_FDATASYNC		fsync
+#elif defined(ANDROID)
+# define MDB_FDATASYNC		fsync
+#endif
+
+#ifndef _WIN32
+#include <pthread.h>
+#ifdef MDB_USE_POSIX_SEM
+# define MDB_USE_HASH		1
+#include <semaphore.h>
+#endif
+#endif
+
+#ifdef USE_VALGRIND
+#include <valgrind/memcheck.h>
+#define VGMEMP_CREATE(h,r,z)    VALGRIND_CREATE_MEMPOOL(h,r,z)
+#define VGMEMP_ALLOC(h,a,s) VALGRIND_MEMPOOL_ALLOC(h,a,s)
+#define VGMEMP_FREE(h,a) VALGRIND_MEMPOOL_FREE(h,a)
+#define VGMEMP_DESTROY(h)	VALGRIND_DESTROY_MEMPOOL(h)
+#define VGMEMP_DEFINED(a,s)	VALGRIND_MAKE_MEM_DEFINED(a,s)
+#else
+#define VGMEMP_CREATE(h,r,z)
+#define VGMEMP_ALLOC(h,a,s)
+#define VGMEMP_FREE(h,a)
+#define VGMEMP_DESTROY(h)
+#define VGMEMP_DEFINED(a,s)
+#endif
+
+#ifndef BYTE_ORDER
+# if (defined(_LITTLE_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(_LITTLE_ENDIAN) && defined(_BIG_ENDIAN))
+/* Solaris just defines one or the other */
+#  define LITTLE_ENDIAN	1234
+#  define BIG_ENDIAN	4321
+#  ifdef _LITTLE_ENDIAN
+#   define BYTE_ORDER  LITTLE_ENDIAN
+#  else
+#   define BYTE_ORDER  BIG_ENDIAN
+#  endif
+# else
+#  define BYTE_ORDER   __BYTE_ORDER
+# endif
+#endif
+
+#ifndef LITTLE_ENDIAN
+#define LITTLE_ENDIAN	__LITTLE_ENDIAN
+#endif
+#ifndef BIG_ENDIAN
+#define BIG_ENDIAN	__BIG_ENDIAN
+#endif
+
+#if defined(__i386) || defined(__x86_64) || defined(_M_IX86)
+#define MISALIGNED_OK	1
+#endif
+
+#include "lmdb.h"
+#include "midl.h"
+
+#if (BYTE_ORDER == LITTLE_ENDIAN) == (BYTE_ORDER == BIG_ENDIAN)
+# error "Unknown or unsupported endianness (BYTE_ORDER)"
+#elif (-6 & 5) || CHAR_BIT != 8 || UINT_MAX < 0xffffffff || ULONG_MAX % 0xFFFF
+# error "Two's complement, reasonably sized integer types, please"
+#endif
+
+#ifdef __GNUC__
+/** Put infrequently used env functions in separate section */
+# ifdef __APPLE__
+#  define	ESECT	__attribute__ ((section("__TEXT,text_env")))
+# else
+#  define	ESECT	__attribute__ ((section("text_env")))
+# endif
+#else
+#define ESECT
+#endif
+
+/** @defgroup internal	LMDB Internals
+ *	@{
+ */
+/** @defgroup compat	Compatibility Macros
+ *	A bunch of macros to minimize the amount of platform-specific ifdefs
+ *	needed throughout the rest of the code. When the features this library
+ *	needs are similar enough to POSIX to be hidden in a one-or-two line
+ *	replacement, this macro approach is used.
+ *	@{
+ */
+
+	/** Features under development */
+#ifndef MDB_DEVEL
+#define MDB_DEVEL 0
+#endif
+
+	/** Wrapper around __func__, which is a C99 feature */
+#if __STDC_VERSION__ >= 199901L
+# define mdb_func_	__func__
+#elif __GNUC__ >= 2 || _MSC_VER >= 1300
+# define mdb_func_	__FUNCTION__
+#else
+/* If a debug message says <mdb_unknown>(), update the #if statements above */
+# define mdb_func_	"<mdb_unknown>"
+#endif
+
+#ifdef _WIN32
+#define MDB_USE_HASH	1
+#define MDB_PIDLOCK	0
+#define THREAD_RET	DWORD
+#define pthread_t	HANDLE
+#define pthread_mutex_t	HANDLE
+#define pthread_cond_t	HANDLE
+#define pthread_key_t	DWORD
+#define pthread_self()	GetCurrentThreadId()
+#define pthread_key_create(x,y)	\
+	((*(x) = TlsAlloc()) == TLS_OUT_OF_INDEXES ? ErrCode() : 0)
+#define pthread_key_delete(x)	TlsFree(x)
+#define pthread_getspecific(x)	TlsGetValue(x)
+#define pthread_setspecific(x,y)	(TlsSetValue(x,y) ? 0 : ErrCode())
+#define pthread_mutex_unlock(x)	ReleaseMutex(*x)
+#define pthread_mutex_lock(x)	WaitForSingleObject(*x, INFINITE)
+#define pthread_cond_signal(x)	SetEvent(*x)
+#define pthread_cond_wait(cond,mutex)	do{SignalObjectAndWait(*mutex, *cond, INFINITE, FALSE); WaitForSingleObject(*mutex, INFINITE);}while(0)
+#define THREAD_CREATE(thr,start,arg)	thr=CreateThread(NULL,0,start,arg,0,NULL)
+#define THREAD_FINISH(thr)	WaitForSingleObject(thr, INFINITE)
+#define LOCK_MUTEX_R(env)	pthread_mutex_lock(&(env)->me_rmutex)
+#define UNLOCK_MUTEX_R(env)	pthread_mutex_unlock(&(env)->me_rmutex)
+#define LOCK_MUTEX_W(env)	pthread_mutex_lock(&(env)->me_wmutex)
+#define UNLOCK_MUTEX_W(env)	pthread_mutex_unlock(&(env)->me_wmutex)
+#define getpid()	GetCurrentProcessId()
+#define	MDB_FDATASYNC(fd)	(!FlushFileBuffers(fd))
+#define	MDB_MSYNC(addr,len,flags)	(!FlushViewOfFile(addr,len))
+#define	ErrCode()	GetLastError()
+#define GET_PAGESIZE(x) {SYSTEM_INFO si; GetSystemInfo(&si); (x) = si.dwPageSize;}
+#define	close(fd)	(CloseHandle(fd) ? 0 : -1)
+#define	munmap(ptr,len)	UnmapViewOfFile(ptr)
+#ifdef PROCESS_QUERY_LIMITED_INFORMATION
+#define MDB_PROCESS_QUERY_LIMITED_INFORMATION PROCESS_QUERY_LIMITED_INFORMATION
+#else
+#define MDB_PROCESS_QUERY_LIMITED_INFORMATION 0x1000
+#endif
+#define	Z	"I"
+#else
+#define THREAD_RET	void *
+#define THREAD_CREATE(thr,start,arg)	pthread_create(&thr,NULL,start,arg)
+#define THREAD_FINISH(thr)	pthread_join(thr,NULL)
+#define	Z	"z"			/**< printf format modifier for size_t */
+
+	/** For MDB_LOCK_FORMAT: True if readers take a pid lock in the lockfile */
+#define MDB_PIDLOCK			1
+
+#ifdef MDB_USE_POSIX_SEM
+
+#define LOCK_MUTEX_R(env)	mdb_sem_wait((env)->me_rmutex)
+#define UNLOCK_MUTEX_R(env)	sem_post((env)->me_rmutex)
+#define LOCK_MUTEX_W(env)	mdb_sem_wait((env)->me_wmutex)
+#define UNLOCK_MUTEX_W(env)	sem_post((env)->me_wmutex)
+
+static int
+mdb_sem_wait(sem_t *sem)
+{
+   int rc;
+   while ((rc = sem_wait(sem)) && (rc = errno) == EINTR) ;
+   return rc;
+}
+
+#else
+	/** Lock the reader mutex.
+	 */
+#define LOCK_MUTEX_R(env)	pthread_mutex_lock(&(env)->me_txns->mti_mutex)
+	/** Unlock the reader mutex.
+	 */
+#define UNLOCK_MUTEX_R(env)	pthread_mutex_unlock(&(env)->me_txns->mti_mutex)
+
+	/** Lock the writer mutex.
+	 *	Only a single write transaction is allowed at a time. Other writers
+	 *	will block waiting for this mutex.
+	 */
+#define LOCK_MUTEX_W(env)	pthread_mutex_lock(&(env)->me_txns->mti_wmutex)
+	/** Unlock the writer mutex.
+	 */
+#define UNLOCK_MUTEX_W(env)	pthread_mutex_unlock(&(env)->me_txns->mti_wmutex)
+#endif	/* MDB_USE_POSIX_SEM */
+
+	/** Get the error code for the last failed system function.
+	 */
+#define	ErrCode()	errno
+
+	/** An abstraction for a file handle.
+	 *	On POSIX systems file handles are small integers. On Windows
+	 *	they're opaque pointers.
+	 */
+#define	HANDLE	int
+
+	/**	A value for an invalid file handle.
+	 *	Mainly used to initialize file variables and signify that they are
+	 *	unused.
+	 */
+#define INVALID_HANDLE_VALUE	(-1)
+
+	/** Get the size of a memory page for the system.
+	 *	This is the basic size that the platform's memory manager uses, and is
+	 *	fundamental to the use of memory-mapped files.
+	 */
+#define	GET_PAGESIZE(x)	((x) = sysconf(_SC_PAGE_SIZE))
+#endif
+
+#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
+#define MNAME_LEN	32
+#else
+#define MNAME_LEN	(sizeof(pthread_mutex_t))
+#endif
+
+/** @} */
+
+#ifndef _WIN32
+/**	A flag for opening a file and requesting synchronous data writes.
+ *	This is only used when writing a meta page. It's not strictly needed;
+ *	we could just do a normal write and then immediately perform a flush.
+ *	But if this flag is available it saves us an extra system call.
+ *
+ *	@note If O_DSYNC is undefined but exists in /usr/include,
+ * preferably set some compiler flag to get the definition.
+ * Otherwise compile with the less efficient -DMDB_DSYNC=O_SYNC.
+ */
+#ifndef MDB_DSYNC
+# define MDB_DSYNC	O_DSYNC
+#endif
+#endif
+
+/** Function for flushing the data of a file. Define this to fsync
+ *	if fdatasync() is not supported.
+ */
+#ifndef MDB_FDATASYNC
+# define MDB_FDATASYNC	fdatasync
+#endif
+
+#ifndef MDB_MSYNC
+# define MDB_MSYNC(addr,len,flags)	msync(addr,len,flags)
+#endif
+
+#ifndef MS_SYNC
+#define	MS_SYNC	1
+#endif
+
+#ifndef MS_ASYNC
+#define	MS_ASYNC	0
+#endif
+
+	/** A page number in the database.
+	 *	Note that 64 bit page numbers are overkill, since pages themselves
+	 *	already represent 12-13 bits of addressable memory, and the OS will
+	 *	always limit applications to a maximum of 63 bits of address space.
+	 *
+	 *	@note In the #MDB_node structure, we only store 48 bits of this value,
+	 *	which thus limits us to only 60 bits of addressable data.
+	 */
+typedef MDB_ID	pgno_t;
+
+	/** A transaction ID.
+	 *	See struct MDB_txn.mt_txnid for details.
+	 */
+typedef MDB_ID	txnid_t;
+
+/** @defgroup debug	Debug Macros
+ *	@{
+ */
+#ifndef MDB_DEBUG
+	/**	Enable debug output.  Needs variable argument macros (a C99 feature).
+	 *	Set this to 1 for copious tracing. Set to 2 to add dumps of all IDLs
+	 *	read from and written to the database (used for free space management).
+	 */
+#define MDB_DEBUG 0
+#endif
+
+#if MDB_DEBUG
+static int mdb_debug;
+static txnid_t mdb_debug_start;
+
+	/**	Print a debug message with printf formatting.
+	 *	Requires double parenthesis around 2 or more args.
+	 */
+# define DPRINTF(args) ((void) ((mdb_debug) && DPRINTF0 args))
+# define DPRINTF0(fmt, ...) \
+	fprintf(stderr, "%s:%d " fmt "\n", mdb_func_, __LINE__, __VA_ARGS__)
+#else
+# define DPRINTF(args)	((void) 0)
+#endif
+	/**	Print a debug string.
+	 *	The string is printed literally, with no format processing.
+	 */
+#define DPUTS(arg)	DPRINTF(("%s", arg))
+	/** Debuging output value of a cursor DBI: Negative in a sub-cursor. */
+#define DDBI(mc) \
+	(((mc)->mc_flags & C_SUB) ? -(int)(mc)->mc_dbi : (int)(mc)->mc_dbi)
+/** @} */
+
+	/**	@brief The maximum size of a database page.
+	 *
+	 *	It is 32k or 64k, since value-PAGEBASE must fit in
+	 *	#MDB_page.%mp_upper.
+	 *
+	 *	LMDB will use database pages < OS pages if needed.
+	 *	That causes more I/O in write transactions: The OS must
+	 *	know (read) the whole page before writing a partial page.
+	 *
+	 *	Note that we don't currently support Huge pages. On Linux,
+	 *	regular data files cannot use Huge pages, and in general
+	 *	Huge pages aren't actually pageable. We rely on the OS
+	 *	demand-pager to read our data and page it out when memory
+	 *	pressure from other processes is high. So until OSs have
+	 *	actual paging support for Huge pages, they're not viable.
+	 */
+#define MAX_PAGESIZE	 (PAGEBASE ? 0x10000 : 0x8000)
+
+	/** The minimum number of keys required in a database page.
+	 *	Setting this to a larger value will place a smaller bound on the
+	 *	maximum size of a data item. Data items larger than this size will
+	 *	be pushed into overflow pages instead of being stored directly in
+	 *	the B-tree node. This value used to default to 4. With a page size
+	 *	of 4096 bytes that meant that any item larger than 1024 bytes would
+	 *	go into an overflow page. That also meant that on average 2-3KB of
+	 *	each overflow page was wasted space. The value cannot be lower than
+	 *	2 because then there would no longer be a tree structure. With this
+	 *	value, items larger than 2KB will go into overflow pages, and on
+	 *	average only 1KB will be wasted.
+	 */
+#define MDB_MINKEYS	 2
+
+	/**	A stamp that identifies a file as an LMDB file.
+	 *	There's nothing special about this value other than that it is easily
+	 *	recognizable, and it will reflect any byte order mismatches.
+	 */
+#define MDB_MAGIC	 0xBEEFC0DE
+
+	/**	The version number for a database's datafile format. */
+#define MDB_DATA_VERSION	 ((MDB_DEVEL) ? 999 : 1)
+	/**	The version number for a database's lockfile format. */
+#define MDB_LOCK_VERSION	 1
+
+	/**	@brief The max size of a key we can write, or 0 for dynamic max.
+	 *
+	 *	Define this as 0 to compute the max from the page size.  511
+	 *	is default for backwards compat: liblmdb <= 0.9.10 can break
+	 *	when modifying a DB with keys/dupsort data bigger than its max.
+	 *	#MDB_DEVEL sets the default to 0.
+	 *
+	 *	Data items in an #MDB_DUPSORT database are also limited to
+	 *	this size, since they're actually keys of a sub-DB.  Keys and
+	 *	#MDB_DUPSORT data items must fit on a node in a regular page.
+	 */
+#ifndef MDB_MAXKEYSIZE
+#define MDB_MAXKEYSIZE	 ((MDB_DEVEL) ? 0 : 511)
+#endif
+
+	/**	The maximum size of a key we can write to the environment. */
+#if MDB_MAXKEYSIZE
+#define ENV_MAXKEY(env)	(MDB_MAXKEYSIZE)
+#else
+#define ENV_MAXKEY(env)	((env)->me_maxkey)
+#endif
+
+	/**	@brief The maximum size of a data item.
+	 *
+	 *	We only store a 32 bit value for node sizes.
+	 */
+#define MAXDATASIZE	0xffffffffUL
+
+#if MDB_DEBUG
+	/**	Key size which fits in a #DKBUF.
+	 *	@ingroup debug
+	 */
+#define DKBUF_MAXKEYSIZE ((MDB_MAXKEYSIZE) > 0 ? (MDB_MAXKEYSIZE) : 511)
+	/**	A key buffer.
+	 *	@ingroup debug
+	 *	This is used for printing a hex dump of a key's contents.
+	 */
+#define DKBUF	char kbuf[DKBUF_MAXKEYSIZE*2+1]
+	/**	Display a key in hex.
+	 *	@ingroup debug
+	 *	Invoke a function to display a key in hex.
+	 */
+#define	DKEY(x)	mdb_dkey(x, kbuf)
+#else
+#define	DKBUF
+#define DKEY(x)	0
+#endif
+
+	/** An invalid page number.
+	 *	Mainly used to denote an empty tree.
+	 */
+#define P_INVALID	 (~(pgno_t)0)
+
+	/** Test if the flags \b f are set in a flag word \b w. */
+#define F_ISSET(w, f)	 (((w) & (f)) == (f))
+
+	/** Round \b n up to an even number. */
+#define EVEN(n)		(((n) + 1U) & -2) /* sign-extending -2 to match n+1U */
+
+	/**	Used for offsets within a single page.
+	 *	Since memory pages are typically 4 or 8KB in size, 12-13 bits,
+	 *	this is plenty.
+	 */
+typedef uint16_t	 indx_t;
+
+	/**	Default size of memory map.
+	 *	This is certainly too small for any actual applications. Apps should always set
+	 *	the size explicitly using #mdb_env_set_mapsize().
+	 */
+#define DEFAULT_MAPSIZE	1048576
+
+/**	@defgroup readers	Reader Lock Table
+ *	Readers don't acquire any locks for their data access. Instead, they
+ *	simply record their transaction ID in the reader table. The reader
+ *	mutex is needed just to find an empty slot in the reader table. The
+ *	slot's address is saved in thread-specific data so that subsequent read
+ *	transactions started by the same thread need no further locking to proceed.
+ *
+ *	If #MDB_NOTLS is set, the slot address is not saved in thread-specific data.
+ *
+ *	No reader table is used if the database is on a read-only filesystem, or
+ *	if #MDB_NOLOCK is set.
+ *
+ *	Since the database uses multi-version concurrency control, readers don't
+ *	actually need any locking. This table is used to keep track of which
+ *	readers are using data from which old transactions, so that we'll know
+ *	when a particular old transaction is no longer in use. Old transactions
+ *	that have discarded any data pages can then have those pages reclaimed
+ *	for use by a later write transaction.
+ *
+ *	The lock table is constructed such that reader slots are aligned with the
+ *	processor's cache line size. Any slot is only ever used by one thread.
+ *	This alignment guarantees that there will be no contention or cache
+ *	thrashing as threads update their own slot info, and also eliminates
+ *	any need for locking when accessing a slot.
+ *
+ *	A writer thread will scan every slot in the table to determine the oldest
+ *	outstanding reader transaction. Any freed pages older than this will be
+ *	reclaimed by the writer. The writer doesn't use any locks when scanning
+ *	this table. This means that there's no guarantee that the writer will
+ *	see the most up-to-date reader info, but that's not required for correct
+ *	operation - all we need is to know the upper bound on the oldest reader,
+ *	we don't care at all about the newest reader. So the only consequence of
+ *	reading stale information here is that old pages might hang around a
+ *	while longer before being reclaimed. That's actually good anyway, because
+ *	the longer we delay reclaiming old pages, the more likely it is that a
+ *	string of contiguous pages can be found after coalescing old pages from
+ *	many old transactions together.
+ *	@{
+ */
+	/**	Number of slots in the reader table.
+	 *	This value was chosen somewhat arbitrarily. 126 readers plus a
+	 *	couple mutexes fit exactly into 8KB on my development machine.
+	 *	Applications should set the table size using #mdb_env_set_maxreaders().
+	 */
+#define DEFAULT_READERS	126
+
+	/**	The size of a CPU cache line in bytes. We want our lock structures
+	 *	aligned to this size to avoid false cache line sharing in the
+	 *	lock table.
+	 *	This value works for most CPUs. For Itanium this should be 128.
+	 */
+#ifndef CACHELINE
+#define CACHELINE	64
+#endif
+
+	/**	The information we store in a single slot of the reader table.
+	 *	In addition to a transaction ID, we also record the process and
+	 *	thread ID that owns a slot, so that we can detect stale information,
+	 *	e.g. threads or processes that went away without cleaning up.
+	 *	@note We currently don't check for stale records. We simply re-init
+	 *	the table when we know that we're the only process opening the
+	 *	lock file.
+	 */
+typedef struct MDB_rxbody {
+	/**	Current Transaction ID when this transaction began, or (txnid_t)-1.
+	 *	Multiple readers that start at the same time will probably have the
+	 *	same ID here. Again, it's not important to exclude them from
+	 *	anything; all we need to know is which version of the DB they
+	 *	started from so we can avoid overwriting any data used in that
+	 *	particular version.
+	 */
+	txnid_t		mrb_txnid;
+	/** The process ID of the process owning this reader txn. */
+	MDB_PID_T	mrb_pid;
+	/** The thread ID of the thread owning this txn. */
+	MDB_THR_T	mrb_tid;
+} MDB_rxbody;
+
+	/** The actual reader record, with cacheline padding. */
+typedef struct MDB_reader {
+	union {
+		MDB_rxbody mrx;
+		/** shorthand for mrb_txnid */
+#define	mr_txnid	mru.mrx.mrb_txnid
+#define	mr_pid	mru.mrx.mrb_pid
+#define	mr_tid	mru.mrx.mrb_tid
+		/** cache line alignment */
+		char pad[(sizeof(MDB_rxbody)+CACHELINE-1) & ~(CACHELINE-1)];
+	} mru;
+} MDB_reader;
+
+	/** The header for the reader table.
+	 *	The table resides in a memory-mapped file. (This is a different file
+	 *	than is used for the main database.)
+	 *
+	 *	For POSIX the actual mutexes reside in the shared memory of this
+	 *	mapped file. On Windows, mutexes are named objects allocated by the
+	 *	kernel; we store the mutex names in this mapped file so that other
+	 *	processes can grab them. This same approach is also used on
+	 *	MacOSX/Darwin (using named semaphores) since MacOSX doesn't support
+	 *	process-shared POSIX mutexes. For these cases where a named object
+	 *	is used, the object name is derived from a 64 bit FNV hash of the
+	 *	environment pathname. As such, naming collisions are extremely
+	 *	unlikely. If a collision occurs, the results are unpredictable.
+	 */
+typedef struct MDB_txbody {
+		/** Stamp identifying this as an LMDB file. It must be set
+		 *	to #MDB_MAGIC. */
+	uint32_t	mtb_magic;
+		/** Format of this lock file. Must be set to #MDB_LOCK_FORMAT. */
+	uint32_t	mtb_format;
+#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
+	char	mtb_rmname[MNAME_LEN];
+#else
+		/** Mutex protecting access to this table.
+		 *	This is the reader lock that #LOCK_MUTEX_R acquires.
+		 */
+	pthread_mutex_t	mtb_mutex;
+#endif
+		/**	The ID of the last transaction committed to the database.
+		 *	This is recorded here only for convenience; the value can always
+		 *	be determined by reading the main database meta pages.
+		 */
+	txnid_t		mtb_txnid;
+		/** The number of slots that have been used in the reader table.
+		 *	This always records the maximum count, it is not decremented
+		 *	when readers release their slots.
+		 */
+	unsigned	mtb_numreaders;
+} MDB_txbody;
+
+	/** The actual reader table definition. */
+typedef struct MDB_txninfo {
+	union {
+		MDB_txbody mtb;
+#define mti_magic	mt1.mtb.mtb_magic
+#define mti_format	mt1.mtb.mtb_format
+#define mti_mutex	mt1.mtb.mtb_mutex
+#define mti_rmname	mt1.mtb.mtb_rmname
+#define mti_txnid	mt1.mtb.mtb_txnid
+#define mti_numreaders	mt1.mtb.mtb_numreaders
+		char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];
+	} mt1;
+	union {
+#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
+		char mt2_wmname[MNAME_LEN];
+#define	mti_wmname	mt2.mt2_wmname
+#else
+		pthread_mutex_t	mt2_wmutex;
+#define mti_wmutex	mt2.mt2_wmutex
+#endif
+		char pad[(MNAME_LEN+CACHELINE-1) & ~(CACHELINE-1)];
+	} mt2;
+	MDB_reader	mti_readers[1];
+} MDB_txninfo;
+
+	/** Lockfile format signature: version, features and field layout */
+#define MDB_LOCK_FORMAT \
+	((uint32_t) \
+	 ((MDB_LOCK_VERSION) \
+	  /* Flags which describe functionality */ \
+	  + (((MDB_PIDLOCK) != 0) << 16)))
+/** @} */
+
+/** Common header for all page types.
+ * Overflow records occupy a number of contiguous pages with no
+ * headers on any page after the first.
+ */
+typedef struct MDB_page {
+#define	mp_pgno	mp_p.p_pgno
+#define	mp_next	mp_p.p_next
+	union {
+		pgno_t		p_pgno;	/**< page number */
+		struct MDB_page *p_next; /**< for in-memory list of freed pages */
+	} mp_p;
+	uint16_t	mp_pad;
+/**	@defgroup mdb_page	Page Flags
+ *	@ingroup internal
+ *	Flags for the page headers.
+ *	@{
+ */
+#define	P_BRANCH	 0x01		/**< branch page */
+#define	P_LEAF		 0x02		/**< leaf page */
+#define	P_OVERFLOW	 0x04		/**< overflow page */
+#define	P_META		 0x08		/**< meta page */
+#define	P_DIRTY		 0x10		/**< dirty page, also set for #P_SUBP pages */
+#define	P_LEAF2		 0x20		/**< for #MDB_DUPFIXED records */
+#define	P_SUBP		 0x40		/**< for #MDB_DUPSORT sub-pages */
+#define	P_LOOSE		 0x4000		/**< page was dirtied then freed, can be reused */
+#define	P_KEEP		 0x8000		/**< leave this page alone during spill */
+/** @} */
+	uint16_t	mp_flags;		/**< @ref mdb_page */
+#define mp_lower	mp_pb.pb.pb_lower
+#define mp_upper	mp_pb.pb.pb_upper
+#define mp_pages	mp_pb.pb_pages
+	union {
+		struct {
+			indx_t		pb_lower;		/**< lower bound of free space */
+			indx_t		pb_upper;		/**< upper bound of free space */
+		} pb;
+		uint32_t	pb_pages;	/**< number of overflow pages */
+	} mp_pb;
+	indx_t		mp_ptrs[1];		/**< dynamic size */
+} MDB_page;
+
+	/** Size of the page header, excluding dynamic data at the end */
+#define PAGEHDRSZ	 ((unsigned) offsetof(MDB_page, mp_ptrs))
+
+	/** Address of first usable data byte in a page, after the header */
+#define METADATA(p)	 ((void *)((char *)(p) + PAGEHDRSZ))
+
+	/** ITS#7713, change PAGEBASE to handle 65536 byte pages */
+#define	PAGEBASE	((MDB_DEVEL) ? PAGEHDRSZ : 0)
+
+	/** Number of nodes on a page */
+#define NUMKEYS(p)	 (((p)->mp_lower - (PAGEHDRSZ-PAGEBASE)) >> 1)
+
+	/** The amount of space remaining in the page */
+#define SIZELEFT(p)	 (indx_t)((p)->mp_upper - (p)->mp_lower)
+
+	/** The percentage of space used in the page, in tenths of a percent. */
+#define PAGEFILL(env, p) (1000L * ((env)->me_psize - PAGEHDRSZ - SIZELEFT(p)) / \
+				((env)->me_psize - PAGEHDRSZ))
+	/** The minimum page fill factor, in tenths of a percent.
+	 *	Pages emptier than this are candidates for merging.
+	 */
+#define FILL_THRESHOLD	 250
+
+	/** Test if a page is a leaf page */
+#define IS_LEAF(p)	 F_ISSET((p)->mp_flags, P_LEAF)
+	/** Test if a page is a LEAF2 page */
+#define IS_LEAF2(p)	 F_ISSET((p)->mp_flags, P_LEAF2)
+	/** Test if a page is a branch page */
+#define IS_BRANCH(p)	 F_ISSET((p)->mp_flags, P_BRANCH)
+	/** Test if a page is an overflow page */
+#define IS_OVERFLOW(p)	 F_ISSET((p)->mp_flags, P_OVERFLOW)
+	/** Test if a page is a sub page */
+#define IS_SUBP(p)	 F_ISSET((p)->mp_flags, P_SUBP)
+
+	/** The number of overflow pages needed to store the given size. */
+#define OVPAGES(size, psize)	((PAGEHDRSZ-1 + (size)) / (psize) + 1)
+
+	/** Link in #MDB_txn.%mt_loose_pgs list */
+#define NEXT_LOOSE_PAGE(p)		(*(MDB_page **)((p) + 2))
+
+	/** Header for a single key/data pair within a page.
+	 * Used in pages of type #P_BRANCH and #P_LEAF without #P_LEAF2.
+	 * We guarantee 2-byte alignment for 'MDB_node's.
+	 */
+typedef struct MDB_node {
+	/** lo and hi are used for data size on leaf nodes and for
+	 * child pgno on branch nodes. On 64 bit platforms, flags
+	 * is also used for pgno. (Branch nodes have no flags).
+	 * They are in host byte order in case that lets some
+	 * accesses be optimized into a 32-bit word access.
+	 */
+#if BYTE_ORDER == LITTLE_ENDIAN
+	unsigned short	mn_lo, mn_hi;	/**< part of data size or pgno */
+#else
+	unsigned short	mn_hi, mn_lo;
+#endif
+/** @defgroup mdb_node Node Flags
+ *	@ingroup internal
+ *	Flags for node headers.
+ *	@{
+ */
+#define F_BIGDATA	 0x01			/**< data put on overflow page */
+#define F_SUBDATA	 0x02			/**< data is a sub-database */
+#define F_DUPDATA	 0x04			/**< data has duplicates */
+
+/** valid flags for #mdb_node_add() */
+#define	NODE_ADD_FLAGS	(F_DUPDATA|F_SUBDATA|MDB_RESERVE|MDB_APPEND)
+
+/** @} */
+	unsigned short	mn_flags;		/**< @ref mdb_node */
+	unsigned short	mn_ksize;		/**< key size */
+	char		mn_data[1];			/**< key and data are appended here */
+} MDB_node;
+
+	/** Size of the node header, excluding dynamic data at the end */
+#define NODESIZE	 offsetof(MDB_node, mn_data)
+
+	/** Bit position of top word in page number, for shifting mn_flags */
+#define PGNO_TOPWORD ((pgno_t)-1 > 0xffffffffu ? 32 : 0)
+
+	/** Size of a node in a branch page with a given key.
+	 *	This is just the node header plus the key, there is no data.
+	 */
+#define INDXSIZE(k)	 (NODESIZE + ((k) == NULL ? 0 : (k)->mv_size))
+
+	/** Size of a node in a leaf page with a given key and data.
+	 *	This is node header plus key plus data size.
+	 */
+#define LEAFSIZE(k, d)	 (NODESIZE + (k)->mv_size + (d)->mv_size)
+
+	/** Address of node \b i in page \b p */
+#define NODEPTR(p, i)	 ((MDB_node *)((char *)(p) + (p)->mp_ptrs[i] + PAGEBASE))
+
+	/** Address of the key for the node */
+#define NODEKEY(node)	 (void *)((node)->mn_data)
+
+	/** Address of the data for a node */
+#define NODEDATA(node)	 (void *)((char *)(node)->mn_data + (node)->mn_ksize)
+
+	/** Get the page number pointed to by a branch node */
+#define NODEPGNO(node) \
+	((node)->mn_lo | ((pgno_t) (node)->mn_hi << 16) | \
+	 (PGNO_TOPWORD ? ((pgno_t) (node)->mn_flags << PGNO_TOPWORD) : 0))
+	/** Set the page number in a branch node */
+#define SETPGNO(node,pgno)	do { \
+	(node)->mn_lo = (pgno) & 0xffff; (node)->mn_hi = (pgno) >> 16; \
+	if (PGNO_TOPWORD) (node)->mn_flags = (pgno) >> PGNO_TOPWORD; } while(0)
+
+	/** Get the size of the data in a leaf node */
+#define NODEDSZ(node)	 ((node)->mn_lo | ((unsigned)(node)->mn_hi << 16))
+	/** Set the size of the data for a leaf node */
+#define SETDSZ(node,size)	do { \
+	(node)->mn_lo = (size) & 0xffff; (node)->mn_hi = (size) >> 16;} while(0)
+	/** The size of a key in a node */
+#define NODEKSZ(node)	 ((node)->mn_ksize)
+
+	/** Copy a page number from src to dst */
+#ifdef MISALIGNED_OK
+#define COPY_PGNO(dst,src)	dst = src
+#else
+#if SIZE_MAX > 4294967295UL
+#define COPY_PGNO(dst,src)	do { \
+	unsigned short *s, *d;	\
+	s = (unsigned short *)&(src);	\
+	d = (unsigned short *)&(dst);	\
+	*d++ = *s++;	\
+	*d++ = *s++;	\
+	*d++ = *s++;	\
+	*d = *s;	\
+} while (0)
+#else
+#define COPY_PGNO(dst,src)	do { \
+	unsigned short *s, *d;	\
+	s = (unsigned short *)&(src);	\
+	d = (unsigned short *)&(dst);	\
+	*d++ = *s++;	\
+	*d = *s;	\
+} while (0)
+#endif
+#endif
+	/** The address of a key in a LEAF2 page.
+	 *	LEAF2 pages are used for #MDB_DUPFIXED sorted-duplicate sub-DBs.
+	 *	There are no node headers, keys are stored contiguously.
+	 */
+#define LEAF2KEY(p, i, ks)	((char *)(p) + PAGEHDRSZ + ((i)*(ks)))
+
+	/** Set the \b node's key into \b keyptr, if requested. */
+#define MDB_GET_KEY(node, keyptr)	{ if ((keyptr) != NULL) { \
+	(keyptr)->mv_size = NODEKSZ(node); (keyptr)->mv_data = NODEKEY(node); } }
+
+	/** Set the \b node's key into \b key. */
+#define MDB_GET_KEY2(node, key)	{ key.mv_size = NODEKSZ(node); key.mv_data = NODEKEY(node); }
+
+	/** Information about a single database in the environment. */
+typedef struct MDB_db {
+	uint32_t	md_pad;		/**< also ksize for LEAF2 pages */
+	uint16_t	md_flags;	/**< @ref mdb_dbi_open */
+	uint16_t	md_depth;	/**< depth of this tree */
+	pgno_t		md_branch_pages;	/**< number of internal pages */
+	pgno_t		md_leaf_pages;		/**< number of leaf pages */
+	pgno_t		md_overflow_pages;	/**< number of overflow pages */
+	size_t		md_entries;		/**< number of data items */
+	pgno_t		md_root;		/**< the root page of this tree */
+} MDB_db;
+
+	/** mdb_dbi_open flags */
+#define MDB_VALID	0x8000		/**< DB handle is valid, for me_dbflags */
+#define PERSISTENT_FLAGS	(0xffff & ~(MDB_VALID))
+#define VALID_FLAGS	(MDB_REVERSEKEY|MDB_DUPSORT|MDB_INTEGERKEY|MDB_DUPFIXED|\
+	MDB_INTEGERDUP|MDB_REVERSEDUP|MDB_CREATE)
+
+	/** Handle for the DB used to track free pages. */
+#define	FREE_DBI	0
+	/** Handle for the default DB. */
+#define	MAIN_DBI	1
+
+	/** Meta page content.
+	 *	A meta page is the start point for accessing a database snapshot.
+	 *	Pages 0-1 are meta pages. Transaction N writes meta page #(N % 2).
+	 */
+typedef struct MDB_meta {
+		/** Stamp identifying this as an LMDB file. It must be set
+		 *	to #MDB_MAGIC. */
+	uint32_t	mm_magic;
+		/** Version number of this lock file. Must be set to #MDB_DATA_VERSION. */
+	uint32_t	mm_version;
+	void		*mm_address;		/**< address for fixed mapping */
+	size_t		mm_mapsize;			/**< size of mmap region */
+	MDB_db		mm_dbs[2];			/**< first is free space, 2nd is main db */
+	/** The size of pages used in this DB */
+#define	mm_psize	mm_dbs[0].md_pad
+	/** Any persistent environment flags. @ref mdb_env */
+#define	mm_flags	mm_dbs[0].md_flags
+	pgno_t		mm_last_pg;			/**< last used page in file */
+	txnid_t		mm_txnid;			/**< txnid that committed this page */
+} MDB_meta;
+
+	/** Buffer for a stack-allocated meta page.
+	 *	The members define size and alignment, and silence type
+	 *	aliasing warnings.  They are not used directly; that could
+	 *	mean incorrectly using several union members in parallel.
+	 */
+typedef union MDB_metabuf {
+	MDB_page	mb_page;
+	struct {
+		char		mm_pad[PAGEHDRSZ];
+		MDB_meta	mm_meta;
+	} mb_metabuf;
+} MDB_metabuf;
+
+	/** Auxiliary DB info.
+	 *	The information here is mostly static/read-only. There is
+	 *	only a single copy of this record in the environment.
+	 */
+typedef struct MDB_dbx {
+	MDB_val		md_name;		/**< name of the database */
+	MDB_cmp_func	*md_cmp;	/**< function for comparing keys */
+	MDB_cmp_func	*md_dcmp;	/**< function for comparing data items */
+	MDB_rel_func	*md_rel;	/**< user relocate function */
+	void		*md_relctx;		/**< user-provided context for md_rel */
+} MDB_dbx;
+
+	/** A database transaction.
+	 *	Every operation requires a transaction handle.
+	 */
+struct MDB_txn {
+	MDB_txn		*mt_parent;		/**< parent of a nested txn */
+	MDB_txn		*mt_child;		/**< nested txn under this txn */
+	pgno_t		mt_next_pgno;	/**< next unallocated page */
+	/** The ID of this transaction. IDs are integers incrementing from 1.
+	 *	Only committed write transactions increment the ID. If a transaction
+	 *	aborts, the ID may be re-used by the next writer.
+	 */
+	txnid_t		mt_txnid;
+	MDB_env		*mt_env;		/**< the DB environment */
+	/** The list of pages that became unused during this transaction.
+	 */
+	MDB_IDL		mt_free_pgs;
+	/** The list of loose pages that became unused and may be reused
+	 *	in this transaction, linked through #NEXT_LOOSE_PAGE(page).
+	 */
+	MDB_page	*mt_loose_pgs;
+	/* #Number of loose pages (#mt_loose_pgs) */
+	int			mt_loose_count;
+	/** The sorted list of dirty pages we temporarily wrote to disk
+	 *	because the dirty list was full. page numbers in here are
+	 *	shifted left by 1, deleted slots have the LSB set.
+	 */
+	MDB_IDL		mt_spill_pgs;
+	union {
+		/** For write txns: Modified pages. Sorted when not MDB_WRITEMAP. */
+		MDB_ID2L	dirty_list;
+		/** For read txns: This thread/txn's reader table slot, or NULL. */
+		MDB_reader	*reader;
+	} mt_u;
+	/** Array of records for each DB known in the environment. */
+	MDB_dbx		*mt_dbxs;
+	/** Array of MDB_db records for each known DB */
+	MDB_db		*mt_dbs;
+	/** Array of sequence numbers for each DB handle */
+	unsigned int	*mt_dbiseqs;
+/** @defgroup mt_dbflag	Transaction DB Flags
+ *	@ingroup internal
+ * @{
+ */
+#define DB_DIRTY	0x01		/**< DB was modified or is DUPSORT data */
+#define DB_STALE	0x02		/**< Named-DB record is older than txnID */
+#define DB_NEW		0x04		/**< Named-DB handle opened in this txn */
+#define DB_VALID	0x08		/**< DB handle is valid, see also #MDB_VALID */
+/** @} */
+	/** In write txns, array of cursors for each DB */
+	MDB_cursor	**mt_cursors;
+	/** Array of flags for each DB */
+	unsigned char	*mt_dbflags;
+#ifdef VL32
+	/** List of read-only pages */
+	MDB_ID2L	mt_rpages;
+#endif
+	/**	Number of DB records in use. This number only ever increments;
+	 *	we don't decrement it when individual DB handles are closed.
+	 */
+	MDB_dbi		mt_numdbs;
+
+/** @defgroup mdb_txn	Transaction Flags
+ *	@ingroup internal
+ *	@{
+ */
+#define MDB_TXN_RDONLY		0x01		/**< read-only transaction */
+#define MDB_TXN_ERROR		0x02		/**< txn is unusable after an error */
+#define MDB_TXN_DIRTY		0x04		/**< must write, even if dirty list is empty */
+#define MDB_TXN_SPILLS		0x08		/**< txn or a parent has spilled pages */
+/** @} */
+	unsigned int	mt_flags;		/**< @ref mdb_txn */
+	/** #dirty_list room: Array size - \#dirty pages visible to this txn.
+	 *	Includes ancestor txns' dirty pages not hidden by other txns'
+	 *	dirty/spilled pages. Thus commit(nested txn) has room to merge
+	 *	dirty_list into mt_parent after freeing hidden mt_parent pages.
+	 */
+	unsigned int	mt_dirty_room;
+};
+
+/** Enough space for 2^32 nodes with minimum of 2 keys per node. I.e., plenty.
+ * At 4 keys per node, enough for 2^64 nodes, so there's probably no need to
+ * raise this on a 64 bit machine.
+ */
+#define CURSOR_STACK		 32
+
+struct MDB_xcursor;
+
+	/** Cursors are used for all DB operations.
+	 *	A cursor holds a path of (page pointer, key index) from the DB
+	 *	root to a position in the DB, plus other state. #MDB_DUPSORT
+	 *	cursors include an xcursor to the current data item. Write txns
+	 *	track their cursors and keep them up to date when data moves.
+	 *	Exception: An xcursor's pointer to a #P_SUBP page can be stale.
+	 *	(A node with #F_DUPDATA but no #F_SUBDATA contains a subpage).
+	 */
+struct MDB_cursor {
+	/** Next cursor on this DB in this txn */
+	MDB_cursor	*mc_next;
+	/** Backup of the original cursor if this cursor is a shadow */
+	MDB_cursor	*mc_backup;
+	/** Context used for databases with #MDB_DUPSORT, otherwise NULL */
+	struct MDB_xcursor	*mc_xcursor;
+	/** The transaction that owns this cursor */
+	MDB_txn		*mc_txn;
+	/** The database handle this cursor operates on */
+	MDB_dbi		mc_dbi;
+	/** The database record for this cursor */
+	MDB_db		*mc_db;
+	/** The database auxiliary record for this cursor */
+	MDB_dbx		*mc_dbx;
+	/** The @ref mt_dbflag for this database */
+	unsigned char	*mc_dbflag;
+	unsigned short 	mc_snum;	/**< number of pushed pages */
+	unsigned short	mc_top;		/**< index of top page, normally mc_snum-1 */
+/** @defgroup mdb_cursor	Cursor Flags
+ *	@ingroup internal
+ *	Cursor state flags.
+ *	@{
+ */
+#define C_INITIALIZED	0x01	/**< cursor has been initialized and is valid */
+#define C_EOF	0x02			/**< No more data */
+#define C_SUB	0x04			/**< Cursor is a sub-cursor */
+#define C_DEL	0x08			/**< last op was a cursor_del */
+#define C_SPLITTING	0x20		/**< Cursor is in page_split */
+#define C_UNTRACK	0x40		/**< Un-track cursor when closing */
+/** @} */
+	unsigned int	mc_flags;	/**< @ref mdb_cursor */
+	MDB_page	*mc_pg[CURSOR_STACK];	/**< stack of pushed pages */
+	indx_t		mc_ki[CURSOR_STACK];	/**< stack of page indices */
+};
+
+	/** Context for sorted-dup records.
+	 *	We could have gone to a fully recursive design, with arbitrarily
+	 *	deep nesting of sub-databases. But for now we only handle these
+	 *	levels - main DB, optional sub-DB, sorted-duplicate DB.
+	 */
+typedef struct MDB_xcursor {
+	/** A sub-cursor for traversing the Dup DB */
+	MDB_cursor mx_cursor;
+	/** The database record for this Dup DB */
+	MDB_db	mx_db;
+	/**	The auxiliary DB record for this Dup DB */
+	MDB_dbx	mx_dbx;
+	/** The @ref mt_dbflag for this Dup DB */
+	unsigned char mx_dbflag;
+} MDB_xcursor;
+
+	/** State of FreeDB old pages, stored in the MDB_env */
+typedef struct MDB_pgstate {
+	pgno_t		*mf_pghead;	/**< Reclaimed freeDB pages, or NULL before use */
+	txnid_t		mf_pglast;	/**< ID of last used record, or 0 if !mf_pghead */
+} MDB_pgstate;
+
+	/** The database environment. */
+struct MDB_env {
+	HANDLE		me_fd;		/**< The main data file */
+	HANDLE		me_lfd;		/**< The lock file */
+	HANDLE		me_mfd;			/**< just for writing the meta pages */
+#if defined(VL32) && defined(_WIN32)
+	HANDLE		me_fmh;		/**< File Mapping handle */
+#endif
+	/** Failed to update the meta page. Probably an I/O error. */
+#define	MDB_FATAL_ERROR	0x80000000U
+	/** Some fields are initialized. */
+#define	MDB_ENV_ACTIVE	0x20000000U
+	/** me_txkey is set */
+#define	MDB_ENV_TXKEY	0x10000000U
+	uint32_t 	me_flags;		/**< @ref mdb_env */
+	unsigned int	me_psize;	/**< DB page size, inited from me_os_psize */
+	unsigned int	me_os_psize;	/**< OS page size, from #GET_PAGESIZE */
+	unsigned int	me_maxreaders;	/**< size of the reader table */
+	unsigned int	me_numreaders;	/**< max numreaders set by this env */
+	MDB_dbi		me_numdbs;		/**< number of DBs opened */
+	MDB_dbi		me_maxdbs;		/**< size of the DB table */
+	MDB_PID_T	me_pid;		/**< process ID of this env */
+	char		*me_path;		/**< path to the DB files */
+	char		*me_map;		/**< the memory map of the data file */
+	MDB_txninfo	*me_txns;		/**< the memory map of the lock file or NULL */
+	MDB_meta	*me_metas[2];	/**< pointers to the two meta pages */
+	void		*me_pbuf;		/**< scratch area for DUPSORT put() */
+	MDB_txn		*me_txn;		/**< current write transaction */
+	MDB_txn		*me_txn0;		/**< prealloc'd write transaction */
+	size_t		me_mapsize;		/**< size of the data memory map */
+	off_t		me_size;		/**< current file size */
+	pgno_t		me_maxpg;		/**< me_mapsize / me_psize */
+	MDB_dbx		*me_dbxs;		/**< array of static DB info */
+	uint16_t	*me_dbflags;	/**< array of flags from MDB_db.md_flags */
+	unsigned int	*me_dbiseqs;	/**< array of dbi sequence numbers */
+	pthread_key_t	me_txkey;	/**< thread-key for readers */
+	txnid_t		me_pgoldest;	/**< ID of oldest reader last time we looked */
+	MDB_pgstate	me_pgstate;		/**< state of old pages from freeDB */
+#	define		me_pglast	me_pgstate.mf_pglast
+#	define		me_pghead	me_pgstate.mf_pghead
+	MDB_page	*me_dpages;		/**< list of malloc'd blocks for re-use */
+	/** IDL of pages that became unused in a write txn */
+	MDB_IDL		me_free_pgs;
+	/** ID2L of pages written during a write txn. Length MDB_IDL_UM_SIZE. */
+	MDB_ID2L	me_dirty_list;
+	/** Max number of freelist items that can fit in a single overflow page */
+	int			me_maxfree_1pg;
+	/** Max size of a node on a page */
+	unsigned int	me_nodemax;
+#if !(MDB_MAXKEYSIZE)
+	unsigned int	me_maxkey;	/**< max size of a key */
+#endif
+	int		me_live_reader;		/**< have liveness lock in reader table */
+#ifdef _WIN32
+	int		me_pidquery;		/**< Used in OpenProcess */
+	HANDLE		me_rmutex;		/* Windows mutexes don't reside in shared mem */
+	HANDLE		me_wmutex;
+#elif defined(MDB_USE_POSIX_SEM)
+	sem_t		*me_rmutex;		/* Shared mutexes are not supported */
+	sem_t		*me_wmutex;
+#endif
+	void		*me_userctx;	 /**< User-settable context */
+	MDB_assert_func *me_assert_func; /**< Callback for assertion failures */
+};
+
+	/** Nested transaction */
+typedef struct MDB_ntxn {
+	MDB_txn		mnt_txn;		/**< the transaction */
+	MDB_pgstate	mnt_pgstate;	/**< parent transaction's saved freestate */
+} MDB_ntxn;
+
+	/** max number of pages to commit in one writev() call */
+#define MDB_COMMIT_PAGES	 64
+#if defined(IOV_MAX) && IOV_MAX < MDB_COMMIT_PAGES
+#undef MDB_COMMIT_PAGES
+#define MDB_COMMIT_PAGES	IOV_MAX
+#endif
+
+	/** max bytes to write in one call */
+#define MAX_WRITE		(0x80000000U >> (sizeof(ssize_t) == 4))
+
+	/** Check \b txn and \b dbi arguments to a function */
+#define TXN_DBI_EXIST(txn, dbi) \
+	((txn) && (dbi) < (txn)->mt_numdbs && ((txn)->mt_dbflags[dbi] & DB_VALID))
+
+	/** Check for misused \b dbi handles */
+#define TXN_DBI_CHANGED(txn, dbi) \
+	((txn)->mt_dbiseqs[dbi] != (txn)->mt_env->me_dbiseqs[dbi])
+
+static int  mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp);
+static int  mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp);
+static int  mdb_page_touch(MDB_cursor *mc);
+
+static int  mdb_page_get(MDB_txn *txn, pgno_t pgno, MDB_page **mp, int *lvl);
+static int  mdb_page_search_root(MDB_cursor *mc,
+			    MDB_val *key, int modify);
+#define MDB_PS_MODIFY	1
+#define MDB_PS_ROOTONLY	2
+#define MDB_PS_FIRST	4
+#define MDB_PS_LAST		8
+static int  mdb_page_search(MDB_cursor *mc,
+			    MDB_val *key, int flags);
+static int	mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst);
+
+#define MDB_SPLIT_REPLACE	MDB_APPENDDUP	/**< newkey is not new */
+static int	mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata,
+				pgno_t newpgno, unsigned int nflags);
+
+static int  mdb_env_read_header(MDB_env *env, MDB_meta *meta);
+static int  mdb_env_pick_meta(const MDB_env *env);
+static int  mdb_env_write_meta(MDB_txn *txn);
+#if !(defined(_WIN32) || defined(MDB_USE_POSIX_SEM)) /* Drop unused excl arg */
+# define mdb_env_close0(env, excl) mdb_env_close1(env)
+#endif
+static void mdb_env_close0(MDB_env *env, int excl);
+
+static MDB_node *mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp);
+static int  mdb_node_add(MDB_cursor *mc, indx_t indx,
+			    MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags);
+static void mdb_node_del(MDB_cursor *mc, int ksize);
+static void mdb_node_shrink(MDB_page *mp, indx_t indx);
+static int	mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst);
+static int  mdb_node_read(MDB_txn *txn, MDB_node *leaf, MDB_val *data);
+static size_t	mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data);
+static size_t	mdb_branch_size(MDB_env *env, MDB_val *key);
+
+static int	mdb_rebalance(MDB_cursor *mc);
+static int	mdb_update_key(MDB_cursor *mc, MDB_val *key);
+
+static void	mdb_cursor_pop(MDB_cursor *mc);
+static int	mdb_cursor_push(MDB_cursor *mc, MDB_page *mp);
+
+static int	mdb_cursor_del0(MDB_cursor *mc);
+static int	mdb_del0(MDB_txn *txn, MDB_dbi dbi, MDB_val *key, MDB_val *data, unsigned flags);
+static int	mdb_cursor_sibling(MDB_cursor *mc, int move_right);
+static int	mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
+static int	mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
+static int	mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op,
+				int *exactp);
+static int	mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data);
+static int	mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data);
+
+static void	mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx);
+static void	mdb_xcursor_init0(MDB_cursor *mc);
+static void	mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node);
+
+static int	mdb_drop0(MDB_cursor *mc, int subs);
+static void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);
+
+/** @cond */
+static MDB_cmp_func	mdb_cmp_memn, mdb_cmp_memnr, mdb_cmp_int, mdb_cmp_cint, mdb_cmp_long;
+/** @endcond */
+
+#ifdef _WIN32
+static SECURITY_DESCRIPTOR mdb_null_sd;
+static SECURITY_ATTRIBUTES mdb_all_sa;
+static int mdb_sec_inited;
+#endif
+
+/** Return the library version info. */
+char *
+mdb_version(int *major, int *minor, int *patch)
+{
+	if (major) *major = MDB_VERSION_MAJOR;
+	if (minor) *minor = MDB_VERSION_MINOR;
+	if (patch) *patch = MDB_VERSION_PATCH;
+	return MDB_VERSION_STRING;
+}
+
+/** Table of descriptions for LMDB @ref errors */
+static char *const mdb_errstr[] = {
+	"MDB_KEYEXIST: Key/data pair already exists",
+	"MDB_NOTFOUND: No matching key/data pair found",
+	"MDB_PAGE_NOTFOUND: Requested page not found",
+	"MDB_CORRUPTED: Located page was wrong type",
+	"MDB_PANIC: Update of meta page failed",
+	"MDB_VERSION_MISMATCH: Database environment version mismatch",
+	"MDB_INVALID: File is not an LMDB file",
+	"MDB_MAP_FULL: Environment mapsize limit reached",
+	"MDB_DBS_FULL: Environment maxdbs limit reached",
+	"MDB_READERS_FULL: Environment maxreaders limit reached",
+	"MDB_TLS_FULL: Thread-local storage keys full - too many environments open",
+	"MDB_TXN_FULL: Transaction has too many dirty pages - transaction too big",
+	"MDB_CURSOR_FULL: Internal error - cursor stack limit reached",
+	"MDB_PAGE_FULL: Internal error - page has no more space",
+	"MDB_MAP_RESIZED: Database contents grew beyond environment mapsize",
+	"MDB_INCOMPATIBLE: Operation and DB incompatible, or DB flags changed",
+	"MDB_BAD_RSLOT: Invalid reuse of reader locktable slot",
+	"MDB_BAD_TXN: Transaction cannot recover - it must be aborted",
+	"MDB_BAD_VALSIZE: Unsupported size of key/DB name/data, or wrong DUPFIXED size",
+	"MDB_BAD_DBI: The specified DBI handle was closed/changed unexpectedly",
+};
+
+char *
+mdb_strerror(int err)
+{
+#ifdef _WIN32
+	/** HACK: pad 4KB on stack over the buf. Return system msgs in buf.
+	 *	This works as long as no function between the call to mdb_strerror
+	 *	and the actual use of the message uses more than 4K of stack.
+	 */
+	char pad[4096];
+	char buf[1024], *ptr = buf;
+#endif
+	int i;
+	if (!err)
+		return ("Successful return: 0");
+
+	if (err >= MDB_KEYEXIST && err <= MDB_LAST_ERRCODE) {
+		i = err - MDB_KEYEXIST;
+		return mdb_errstr[i];
+	}
+
+#ifdef _WIN32
+	/* These are the C-runtime error codes we use. The comment indicates
+	 * their numeric value, and the Win32 error they would correspond to
+	 * if the error actually came from a Win32 API. A major mess, we should
+	 * have used LMDB-specific error codes for everything.
+	 */
+	switch(err) {
+	case ENOENT:	/* 2, FILE_NOT_FOUND */
+	case EIO:		/* 5, ACCESS_DENIED */
+	case ENOMEM:	/* 12, INVALID_ACCESS */
+	case EACCES:	/* 13, INVALID_DATA */
+	case EBUSY:		/* 16, CURRENT_DIRECTORY */
+	case EINVAL:	/* 22, BAD_COMMAND */
+	case ENOSPC:	/* 28, OUT_OF_PAPER */
+		return strerror(err);
+	default:
+		;
+	}
+	buf[0] = 0;
+	FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM |
+		FORMAT_MESSAGE_IGNORE_INSERTS,
+		NULL, err, 0, ptr, sizeof(buf), pad);
+	return ptr;
+#else
+	return strerror(err);
+#endif
+}
+
+/** assert(3) variant in cursor context */
+#define mdb_cassert(mc, expr)	mdb_assert0((mc)->mc_txn->mt_env, expr, #expr)
+/** assert(3) variant in transaction context */
+#define mdb_tassert(mc, expr)	mdb_assert0((txn)->mt_env, expr, #expr)
+/** assert(3) variant in environment context */
+#define mdb_eassert(env, expr)	mdb_assert0(env, expr, #expr)
+
+#ifndef NDEBUG
+# define mdb_assert0(env, expr, expr_txt) ((expr) ? (void)0 : \
+		mdb_assert_fail(env, expr_txt, mdb_func_, __FILE__, __LINE__))
+
+static void
+mdb_assert_fail(MDB_env *env, const char *expr_txt,
+	const char *func, const char *file, int line)
+{
+	char buf[400];
+	sprintf(buf, "%.100s:%d: Assertion '%.200s' failed in %.40s()",
+		file, line, expr_txt, func);
+	if (env->me_assert_func)
+		env->me_assert_func(env, buf);
+	fprintf(stderr, "%s\n", buf);
+	abort();
+}
+#else
+# define mdb_assert0(env, expr, expr_txt) ((void) 0)
+#endif /* NDEBUG */
+
+#if MDB_DEBUG
+/** Return the page number of \b mp which may be sub-page, for debug output */
+static pgno_t
+mdb_dbg_pgno(MDB_page *mp)
+{
+	pgno_t ret;
+	COPY_PGNO(ret, mp->mp_pgno);
+	return ret;
+}
+
+/** Display a key in hexadecimal and return the address of the result.
+ * @param[in] key the key to display
+ * @param[in] buf the buffer to write into. Should always be #DKBUF.
+ * @return The key in hexadecimal form.
+ */
+char *
+mdb_dkey(MDB_val *key, char *buf)
+{
+	char *ptr = buf;
+	unsigned char *c = key->mv_data;
+	unsigned int i;
+
+	if (!key)
+		return "";
+
+	if (key->mv_size > DKBUF_MAXKEYSIZE)
+		return "MDB_MAXKEYSIZE";
+	/* may want to make this a dynamic check: if the key is mostly
+	 * printable characters, print it as-is instead of converting to hex.
+	 */
+#if 1
+	buf[0] = '\0';
+	for (i=0; i<key->mv_size; i++)
+		ptr += sprintf(ptr, "%02x", *c++);
+#else
+	sprintf(buf, "%.*s", key->mv_size, key->mv_data);
+#endif
+	return buf;
+}
+
+static const char *
+mdb_leafnode_type(MDB_node *n)
+{
+	static char *const tp[2][2] = {{"", ": DB"}, {": sub-page", ": sub-DB"}};
+	return F_ISSET(n->mn_flags, F_BIGDATA) ? ": overflow page" :
+		tp[F_ISSET(n->mn_flags, F_DUPDATA)][F_ISSET(n->mn_flags, F_SUBDATA)];
+}
+
+/** Display all the keys in the page. */
+void
+mdb_page_list(MDB_page *mp)
+{
+	pgno_t pgno = mdb_dbg_pgno(mp);
+	const char *type, *state = (mp->mp_flags & P_DIRTY) ? ", dirty" : "";
+	MDB_node *node;
+	unsigned int i, nkeys, nsize, total = 0;
+	MDB_val key;
+	DKBUF;
+
+	switch (mp->mp_flags & (P_BRANCH|P_LEAF|P_LEAF2|P_META|P_OVERFLOW|P_SUBP)) {
+	case P_BRANCH:              type = "Branch page";		break;
+	case P_LEAF:                type = "Leaf page";			break;
+	case P_LEAF|P_SUBP:         type = "Sub-page";			break;
+	case P_LEAF|P_LEAF2:        type = "LEAF2 page";		break;
+	case P_LEAF|P_LEAF2|P_SUBP: type = "LEAF2 sub-page";	break;
+	case P_OVERFLOW:
+		fprintf(stderr, "Overflow page %"Z"u pages %u%s\n",
+			pgno, mp->mp_pages, state);
+		return;
+	case P_META:
+		fprintf(stderr, "Meta-page %"Z"u txnid %"Z"u\n",
+			pgno, ((MDB_meta *)METADATA(mp))->mm_txnid);
+		return;
+	default:
+		fprintf(stderr, "Bad page %"Z"u flags 0x%u\n", pgno, mp->mp_flags);
+		return;
+	}
+
+	nkeys = NUMKEYS(mp);
+	fprintf(stderr, "%s %"Z"u numkeys %d%s\n", type, pgno, nkeys, state);
+
+	for (i=0; i<nkeys; i++) {
+		if (IS_LEAF2(mp)) {	/* LEAF2 pages have no mp_ptrs[] or node headers */
+			key.mv_size = nsize = mp->mp_pad;
+			key.mv_data = LEAF2KEY(mp, i, nsize);
+			total += nsize;
+			fprintf(stderr, "key %d: nsize %d, %s\n", i, nsize, DKEY(&key));
+			continue;
+		}
+		node = NODEPTR(mp, i);
+		key.mv_size = node->mn_ksize;
+		key.mv_data = node->mn_data;
+		nsize = NODESIZE + key.mv_size;
+		if (IS_BRANCH(mp)) {
+			fprintf(stderr, "key %d: page %"Z"u, %s\n", i, NODEPGNO(node),
+				DKEY(&key));
+			total += nsize;
+		} else {
+			if (F_ISSET(node->mn_flags, F_BIGDATA))
+				nsize += sizeof(pgno_t);
+			else
+				nsize += NODEDSZ(node);
+			total += nsize;
+			nsize += sizeof(indx_t);
+			fprintf(stderr, "key %d: nsize %d, %s%s\n",
+				i, nsize, DKEY(&key), mdb_leafnode_type(node));
+		}
+		total = EVEN(total);
+	}
+	fprintf(stderr, "Total: header %d + contents %d + unused %d\n",
+		IS_LEAF2(mp) ? PAGEHDRSZ : PAGEBASE + mp->mp_lower, total, SIZELEFT(mp));
+}
+
+void
+mdb_cursor_chk(MDB_cursor *mc)
+{
+	unsigned int i;
+	MDB_node *node;
+	MDB_page *mp;
+
+	if (!mc->mc_snum && !(mc->mc_flags & C_INITIALIZED)) return;
+	for (i=0; i<mc->mc_top; i++) {
+		mp = mc->mc_pg[i];
+		node = NODEPTR(mp, mc->mc_ki[i]);
+		if (NODEPGNO(node) != mc->mc_pg[i+1]->mp_pgno)
+			printf("oops!\n");
+	}
+	if (mc->mc_ki[i] >= NUMKEYS(mc->mc_pg[i]))
+		printf("ack!\n");
+}
+#endif
+
+#if (MDB_DEBUG) > 2
+/** Count all the pages in each DB and in the freelist
+ *  and make sure it matches the actual number of pages
+ *  being used.
+ *  All named DBs must be open for a correct count.
+ */
+static void mdb_audit(MDB_txn *txn)
+{
+	MDB_cursor mc;
+	MDB_val key, data;
+	MDB_ID freecount, count;
+	MDB_dbi i;
+	int rc;
+
+	freecount = 0;
+	mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
+	while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)
+		freecount += *(MDB_ID *)data.mv_data;
+	mdb_tassert(txn, rc == MDB_NOTFOUND);
+
+	count = 0;
+	for (i = 0; i<txn->mt_numdbs; i++) {
+		MDB_xcursor mx;
+		if (!(txn->mt_dbflags[i] & DB_VALID))
+			continue;
+		mdb_cursor_init(&mc, txn, i, &mx);
+		if (txn->mt_dbs[i].md_root == P_INVALID)
+			continue;
+		count += txn->mt_dbs[i].md_branch_pages +
+			txn->mt_dbs[i].md_leaf_pages +
+			txn->mt_dbs[i].md_overflow_pages;
+		if (txn->mt_dbs[i].md_flags & MDB_DUPSORT) {
+			rc = mdb_page_search(&mc, NULL, MDB_PS_FIRST);
+			for (; rc == MDB_SUCCESS; rc = mdb_cursor_sibling(&mc, 1)) {
+				unsigned j;
+				MDB_page *mp;
+				mp = mc.mc_pg[mc.mc_top];
+				for (j=0; j<NUMKEYS(mp); j++) {
+					MDB_node *leaf = NODEPTR(mp, j);
+					if (leaf->mn_flags & F_SUBDATA) {
+						MDB_db db;
+						memcpy(&db, NODEDATA(leaf), sizeof(db));
+						count += db.md_branch_pages + db.md_leaf_pages +
+							db.md_overflow_pages;
+					}
+				}
+			}
+			mdb_tassert(txn, rc == MDB_NOTFOUND);
+		}
+	}
+	if (freecount + count + 2 /* metapages */ != txn->mt_next_pgno) {
+		fprintf(stderr, "audit: %lu freecount: %lu count: %lu total: %lu next_pgno: %lu\n",
+			txn->mt_txnid, freecount, count+2, freecount+count+2, txn->mt_next_pgno);
+	}
+}
+#endif
+
+int
+mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
+{
+	return txn->mt_dbxs[dbi].md_cmp(a, b);
+}
+
+int
+mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
+{
+	return txn->mt_dbxs[dbi].md_dcmp(a, b);
+}
+
+/** Allocate memory for a page.
+ * Re-use old malloc'd pages first for singletons, otherwise just malloc.
+ */
+static MDB_page *
+mdb_page_malloc(MDB_txn *txn, unsigned num)
+{
+	MDB_env *env = txn->mt_env;
+	MDB_page *ret = env->me_dpages;
+	size_t psize = env->me_psize, sz = psize, off;
+	/* For ! #MDB_NOMEMINIT, psize counts how much to init.
+	 * For a single page alloc, we init everything after the page header.
+	 * For multi-page, we init the final page; if the caller needed that
+	 * many pages they will be filling in at least up to the last page.
+	 */
+	if (num == 1) {
+		if (ret) {
+			VGMEMP_ALLOC(env, ret, sz);
+			VGMEMP_DEFINED(ret, sizeof(ret->mp_next));
+			env->me_dpages = ret->mp_next;
+			return ret;
+		}
+		psize -= off = PAGEHDRSZ;
+	} else {
+		sz *= num;
+		off = sz - psize;
+	}
+	if ((ret = malloc(sz)) != NULL) {
+		VGMEMP_ALLOC(env, ret, sz);
+		if (!(env->me_flags & MDB_NOMEMINIT)) {
+			memset((char *)ret + off, 0, psize);
+			ret->mp_pad = 0;
+		}
+	} else {
+		txn->mt_flags |= MDB_TXN_ERROR;
+	}
+	return ret;
+}
+/** Free a single page.
+ * Saves single pages to a list, for future reuse.
+ * (This is not used for multi-page overflow pages.)
+ */
+static void
+mdb_page_free(MDB_env *env, MDB_page *mp)
+{
+	mp->mp_next = env->me_dpages;
+	VGMEMP_FREE(env, mp);
+	env->me_dpages = mp;
+}
+
+/** Free a dirty page */
+static void
+mdb_dpage_free(MDB_env *env, MDB_page *dp)
+{
+	if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
+		mdb_page_free(env, dp);
+	} else {
+		/* large pages just get freed directly */
+		VGMEMP_FREE(env, dp);
+		free(dp);
+	}
+}
+
+/**	Return all dirty pages to dpage list */
+static void
+mdb_dlist_free(MDB_txn *txn)
+{
+	MDB_env *env = txn->mt_env;
+	MDB_ID2L dl = txn->mt_u.dirty_list;
+	unsigned i, n = dl[0].mid;
+
+	for (i = 1; i <= n; i++) {
+		mdb_dpage_free(env, dl[i].mptr);
+	}
+	dl[0].mid = 0;
+}
+
+/** Loosen or free a single page.
+ * Saves single pages to a list for future reuse
+ * in this same txn. It has been pulled from the freeDB
+ * and already resides on the dirty list, but has been
+ * deleted. Use these pages first before pulling again
+ * from the freeDB.
+ *
+ * If the page wasn't dirtied in this txn, just add it
+ * to this txn's free list.
+ */
+static int
+mdb_page_loose(MDB_cursor *mc, MDB_page *mp)
+{
+	int loose = 0;
+	pgno_t pgno = mp->mp_pgno;
+	MDB_txn *txn = mc->mc_txn;
+
+	if ((mp->mp_flags & P_DIRTY) && mc->mc_dbi != FREE_DBI) {
+		if (txn->mt_parent) {
+			MDB_ID2 *dl = txn->mt_u.dirty_list;
+			/* If txn has a parent, make sure the page is in our
+			 * dirty list.
+			 */
+			if (dl[0].mid) {
+				unsigned x = mdb_mid2l_search(dl, pgno);
+				if (x <= dl[0].mid && dl[x].mid == pgno) {
+					if (mp != dl[x].mptr) { /* bad cursor? */
+						mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
+						txn->mt_flags |= MDB_TXN_ERROR;
+						return MDB_CORRUPTED;
+					}
+					/* ok, it's ours */
+					loose = 1;
+				}
+			}
+		} else {
+			/* no parent txn, so it's just ours */
+			loose = 1;
+		}
+	}
+	if (loose) {
+		DPRINTF(("loosen db %d page %"Z"u", DDBI(mc),
+			mp->mp_pgno));
+		NEXT_LOOSE_PAGE(mp) = txn->mt_loose_pgs;
+		txn->mt_loose_pgs = mp;
+		txn->mt_loose_count++;
+		mp->mp_flags |= P_LOOSE;
+	} else {
+		int rc = mdb_midl_append(&txn->mt_free_pgs, pgno);
+		if (rc)
+			return rc;
+	}
+
+	return MDB_SUCCESS;
+}
+
+/** Set or clear P_KEEP in dirty, non-overflow, non-sub pages watched by txn.
+ * @param[in] mc A cursor handle for the current operation.
+ * @param[in] pflags Flags of the pages to update:
+ * P_DIRTY to set P_KEEP, P_DIRTY|P_KEEP to clear it.
+ * @param[in] all No shortcuts. Needed except after a full #mdb_page_flush().
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_pages_xkeep(MDB_cursor *mc, unsigned pflags, int all)
+{
+	enum { Mask = P_SUBP|P_DIRTY|P_LOOSE|P_KEEP };
+	MDB_txn *txn = mc->mc_txn;
+	MDB_cursor *m3;
+	MDB_xcursor *mx;
+	MDB_page *dp, *mp;
+	MDB_node *leaf;
+	unsigned i, j;
+	int rc = MDB_SUCCESS, level;
+
+	/* Mark pages seen by cursors */
+	if (mc->mc_flags & C_UNTRACK)
+		mc = NULL;				/* will find mc in mt_cursors */
+	for (i = txn->mt_numdbs;; mc = txn->mt_cursors[--i]) {
+		for (; mc; mc=mc->mc_next) {
+			if (!(mc->mc_flags & C_INITIALIZED))
+				continue;
+			for (m3 = mc;; m3 = &mx->mx_cursor) {
+				mp = NULL;
+				for (j=0; j<m3->mc_snum; j++) {
+					mp = m3->mc_pg[j];
+					if ((mp->mp_flags & Mask) == pflags)
+						mp->mp_flags ^= P_KEEP;
+				}
+				mx = m3->mc_xcursor;
+				/* Proceed to mx if it is at a sub-database */
+				if (! (mx && (mx->mx_cursor.mc_flags & C_INITIALIZED)))
+					break;
+				if (! (mp && (mp->mp_flags & P_LEAF)))
+					break;
+				leaf = NODEPTR(mp, m3->mc_ki[j-1]);
+				if (!(leaf->mn_flags & F_SUBDATA))
+					break;
+			}
+		}
+		if (i == 0)
+			break;
+	}
+
+	if (all) {
+		/* Mark dirty root pages */
+		for (i=0; i<txn->mt_numdbs; i++) {
+			if (txn->mt_dbflags[i] & DB_DIRTY) {
+				pgno_t pgno = txn->mt_dbs[i].md_root;
+				if (pgno == P_INVALID)
+					continue;
+				if ((rc = mdb_page_get(txn, pgno, &dp, &level)) != MDB_SUCCESS)
+					break;
+				if ((dp->mp_flags & Mask) == pflags && level <= 1)
+					dp->mp_flags ^= P_KEEP;
+			}
+		}
+	}
+
+	return rc;
+}
+
+static int mdb_page_flush(MDB_txn *txn, int keep);
+
+/**	Spill pages from the dirty list back to disk.
+ * This is intended to prevent running into #MDB_TXN_FULL situations,
+ * but note that they may still occur in a few cases:
+ *	1) our estimate of the txn size could be too small. Currently this
+ *	 seems unlikely, except with a large number of #MDB_MULTIPLE items.
+ *	2) child txns may run out of space if their parents dirtied a
+ *	 lot of pages and never spilled them. TODO: we probably should do
+ *	 a preemptive spill during #mdb_txn_begin() of a child txn, if
+ *	 the parent's dirty_room is below a given threshold.
+ *
+ * Otherwise, if not using nested txns, it is expected that apps will
+ * not run into #MDB_TXN_FULL any more. The pages are flushed to disk
+ * the same way as for a txn commit, e.g. their P_DIRTY flag is cleared.
+ * If the txn never references them again, they can be left alone.
+ * If the txn only reads them, they can be used without any fuss.
+ * If the txn writes them again, they can be dirtied immediately without
+ * going thru all of the work of #mdb_page_touch(). Such references are
+ * handled by #mdb_page_unspill().
+ *
+ * Also note, we never spill DB root pages, nor pages of active cursors,
+ * because we'll need these back again soon anyway. And in nested txns,
+ * we can't spill a page in a child txn if it was already spilled in a
+ * parent txn. That would alter the parent txns' data even though
+ * the child hasn't committed yet, and we'd have no way to undo it if
+ * the child aborted.
+ *
+ * @param[in] m0 cursor A cursor handle identifying the transaction and
+ *	database for which we are checking space.
+ * @param[in] key For a put operation, the key being stored.
+ * @param[in] data For a put operation, the data being stored.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_page_spill(MDB_cursor *m0, MDB_val *key, MDB_val *data)
+{
+	MDB_txn *txn = m0->mc_txn;
+	MDB_page *dp;
+	MDB_ID2L dl = txn->mt_u.dirty_list;
+	unsigned int i, j, need;
+	int rc;
+
+	if (m0->mc_flags & C_SUB)
+		return MDB_SUCCESS;
+
+	/* Estimate how much space this op will take */
+	i = m0->mc_db->md_depth;
+	/* Named DBs also dirty the main DB */
+	if (m0->mc_dbi > MAIN_DBI)
+		i += txn->mt_dbs[MAIN_DBI].md_depth;
+	/* For puts, roughly factor in the key+data size */
+	if (key)
+		i += (LEAFSIZE(key, data) + txn->mt_env->me_psize) / txn->mt_env->me_psize;
+	i += i;	/* double it for good measure */
+	need = i;
+
+	if (txn->mt_dirty_room > i)
+		return MDB_SUCCESS;
+
+	if (!txn->mt_spill_pgs) {
+		txn->mt_spill_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX);
+		if (!txn->mt_spill_pgs)
+			return ENOMEM;
+	} else {
+		/* purge deleted slots */
+		MDB_IDL sl = txn->mt_spill_pgs;
+		unsigned int num = sl[0];
+		j=0;
+		for (i=1; i<=num; i++) {
+			if (!(sl[i] & 1))
+				sl[++j] = sl[i];
+		}
+		sl[0] = j;
+	}
+
+	/* Preserve pages which may soon be dirtied again */
+	if ((rc = mdb_pages_xkeep(m0, P_DIRTY, 1)) != MDB_SUCCESS)
+		goto done;
+
+	/* Less aggressive spill - we originally spilled the entire dirty list,
+	 * with a few exceptions for cursor pages and DB root pages. But this
+	 * turns out to be a lot of wasted effort because in a large txn many
+	 * of those pages will need to be used again. So now we spill only 1/8th
+	 * of the dirty pages. Testing revealed this to be a good tradeoff,
+	 * better than 1/2, 1/4, or 1/10.
+	 */
+	if (need < MDB_IDL_UM_MAX / 8)
+		need = MDB_IDL_UM_MAX / 8;
+
+	/* Save the page IDs of all the pages we're flushing */
+	/* flush from the tail forward, this saves a lot of shifting later on. */
+	for (i=dl[0].mid; i && need; i--) {
+		MDB_ID pn = dl[i].mid << 1;
+		dp = dl[i].mptr;
+		if (dp->mp_flags & (P_LOOSE|P_KEEP))
+			continue;
+		/* Can't spill twice, make sure it's not already in a parent's
+		 * spill list.
+		 */
+		if (txn->mt_parent) {
+			MDB_txn *tx2;
+			for (tx2 = txn->mt_parent; tx2; tx2 = tx2->mt_parent) {
+				if (tx2->mt_spill_pgs) {
+					j = mdb_midl_search(tx2->mt_spill_pgs, pn);
+					if (j <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[j] == pn) {
+						dp->mp_flags |= P_KEEP;
+						break;
+					}
+				}
+			}
+			if (tx2)
+				continue;
+		}
+		if ((rc = mdb_midl_append(&txn->mt_spill_pgs, pn)))
+			goto done;
+		need--;
+	}
+	mdb_midl_sort(txn->mt_spill_pgs);
+
+	/* Flush the spilled part of dirty list */
+	if ((rc = mdb_page_flush(txn, i)) != MDB_SUCCESS)
+		goto done;
+
+	/* Reset any dirty pages we kept that page_flush didn't see */
+	rc = mdb_pages_xkeep(m0, P_DIRTY|P_KEEP, i);
+
+done:
+	txn->mt_flags |= rc ? MDB_TXN_ERROR : MDB_TXN_SPILLS;
+	return rc;
+}
+
+/** Find oldest txnid still referenced. Expects txn->mt_txnid > 0. */
+static txnid_t
+mdb_find_oldest(MDB_txn *txn)
+{
+	int i;
+	txnid_t mr, oldest = txn->mt_txnid - 1;
+	if (txn->mt_env->me_txns) {
+		MDB_reader *r = txn->mt_env->me_txns->mti_readers;
+		for (i = txn->mt_env->me_txns->mti_numreaders; --i >= 0; ) {
+			if (r[i].mr_pid) {
+				mr = r[i].mr_txnid;
+				if (oldest > mr)
+					oldest = mr;
+			}
+		}
+	}
+	return oldest;
+}
+
+/** Add a page to the txn's dirty list */
+static void
+mdb_page_dirty(MDB_txn *txn, MDB_page *mp)
+{
+	MDB_ID2 mid;
+	int rc, (*insert)(MDB_ID2L, MDB_ID2 *);
+
+	if (txn->mt_env->me_flags & MDB_WRITEMAP) {
+		insert = mdb_mid2l_append;
+	} else {
+		insert = mdb_mid2l_insert;
+	}
+	mid.mid = mp->mp_pgno;
+	mid.mptr = mp;
+	rc = insert(txn->mt_u.dirty_list, &mid);
+	mdb_tassert(txn, rc == 0);
+	txn->mt_dirty_room--;
+}
+
+/** Allocate page numbers and memory for writing.  Maintain me_pglast,
+ * me_pghead and mt_next_pgno.
+ *
+ * If there are free pages available from older transactions, they
+ * are re-used first. Otherwise allocate a new page at mt_next_pgno.
+ * Do not modify the freedB, just merge freeDB records into me_pghead[]
+ * and move me_pglast to say which records were consumed.  Only this
+ * function can create me_pghead and move me_pglast/mt_next_pgno.
+ * @param[in] mc cursor A cursor handle identifying the transaction and
+ *	database for which we are allocating.
+ * @param[in] num the number of pages to allocate.
+ * @param[out] mp Address of the allocated page(s). Requests for multiple pages
+ *  will always be satisfied by a single contiguous chunk of memory.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
+{
+#ifdef MDB_PARANOID	/* Seems like we can ignore this now */
+	/* Get at most <Max_retries> more freeDB records once me_pghead
+	 * has enough pages.  If not enough, use new pages from the map.
+	 * If <Paranoid> and mc is updating the freeDB, only get new
+	 * records if me_pghead is empty. Then the freelist cannot play
+	 * catch-up with itself by growing while trying to save it.
+	 */
+	enum { Paranoid = 1, Max_retries = 500 };
+#else
+	enum { Paranoid = 0, Max_retries = INT_MAX /*infinite*/ };
+#endif
+	int rc, retry = num * 60;
+	MDB_txn *txn = mc->mc_txn;
+	MDB_env *env = txn->mt_env;
+	pgno_t pgno, *mop = env->me_pghead;
+	unsigned i, j, mop_len = mop ? mop[0] : 0, n2 = num-1;
+	MDB_page *np;
+	txnid_t oldest = 0, last;
+	MDB_cursor_op op;
+	MDB_cursor m2;
+	int found_old = 0;
+
+	/* If there are any loose pages, just use them */
+	if (num == 1 && txn->mt_loose_pgs) {
+		np = txn->mt_loose_pgs;
+		txn->mt_loose_pgs = NEXT_LOOSE_PAGE(np);
+		txn->mt_loose_count--;
+		DPRINTF(("db %d use loose page %"Z"u", DDBI(mc),
+				np->mp_pgno));
+		*mp = np;
+		return MDB_SUCCESS;
+	}
+
+	*mp = NULL;
+
+	/* If our dirty list is already full, we can't do anything */
+	if (txn->mt_dirty_room == 0) {
+		rc = MDB_TXN_FULL;
+		goto fail;
+	}
+
+	for (op = MDB_FIRST;; op = MDB_NEXT) {
+		MDB_val key, data;
+		MDB_node *leaf;
+		pgno_t *idl;
+
+		/* Seek a big enough contiguous page range. Prefer
+		 * pages at the tail, just truncating the list.
+		 */
+		if (mop_len > n2) {
+			i = mop_len;
+			do {
+				pgno = mop[i];
+				if (mop[i-n2] == pgno+n2)
+					goto search_done;
+			} while (--i > n2);
+			if (--retry < 0)
+				break;
+		}
+
+		if (op == MDB_FIRST) {	/* 1st iteration */
+			/* Prepare to fetch more and coalesce */
+			last = env->me_pglast;
+			oldest = env->me_pgoldest;
+			mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
+			if (last) {
+				op = MDB_SET_RANGE;
+				key.mv_data = &last; /* will look up last+1 */
+				key.mv_size = sizeof(last);
+			}
+			if (Paranoid && mc->mc_dbi == FREE_DBI)
+				retry = -1;
+		}
+		if (Paranoid && retry < 0 && mop_len)
+			break;
+
+		last++;
+		/* Do not fetch more if the record will be too recent */
+		if (oldest <= last) {
+			if (!found_old) {
+				oldest = mdb_find_oldest(txn);
+				env->me_pgoldest = oldest;
+				found_old = 1;
+			}
+			if (oldest <= last)
+				break;
+		}
+		rc = mdb_cursor_get(&m2, &key, NULL, op);
+		if (rc) {
+			if (rc == MDB_NOTFOUND)
+				break;
+			goto fail;
+		}
+		last = *(txnid_t*)key.mv_data;
+		if (oldest <= last) {
+			if (!found_old) {
+				oldest = mdb_find_oldest(txn);
+				env->me_pgoldest = oldest;
+				found_old = 1;
+			}
+			if (oldest <= last)
+				break;
+		}
+		np = m2.mc_pg[m2.mc_top];
+		leaf = NODEPTR(np, m2.mc_ki[m2.mc_top]);
+		if ((rc = mdb_node_read(txn, leaf, &data)) != MDB_SUCCESS)
+			return rc;
+
+		idl = (MDB_ID *) data.mv_data;
+		i = idl[0];
+		if (!mop) {
+			if (!(env->me_pghead = mop = mdb_midl_alloc(i))) {
+				rc = ENOMEM;
+				goto fail;
+			}
+		} else {
+			if ((rc = mdb_midl_need(&env->me_pghead, i)) != 0)
+				goto fail;
+			mop = env->me_pghead;
+		}
+		env->me_pglast = last;
+#if (MDB_DEBUG) > 1
+		DPRINTF(("IDL read txn %"Z"u root %"Z"u num %u",
+			last, txn->mt_dbs[FREE_DBI].md_root, i));
+		for (j = i; j; j--)
+			DPRINTF(("IDL %"Z"u", idl[j]));
+#endif
+		/* Merge in descending sorted order */
+		mdb_midl_xmerge(mop, idl);
+		mop_len = mop[0];
+	}
+
+	/* Use new pages from the map when nothing suitable in the freeDB */
+	i = 0;
+	pgno = txn->mt_next_pgno;
+	if (pgno + num >= env->me_maxpg) {
+			DPUTS("DB size maxed out");
+			rc = MDB_MAP_FULL;
+			goto fail;
+	}
+
+search_done:
+	if (env->me_flags & MDB_WRITEMAP) {
+		np = (MDB_page *)(env->me_map + env->me_psize * pgno);
+	} else {
+		if (!(np = mdb_page_malloc(txn, num))) {
+			rc = ENOMEM;
+			goto fail;
+		}
+	}
+	if (i) {
+		mop[0] = mop_len -= num;
+		/* Move any stragglers down */
+		for (j = i-num; j < mop_len; )
+			mop[++j] = mop[++i];
+	} else {
+		txn->mt_next_pgno = pgno + num;
+	}
+	np->mp_pgno = pgno;
+	mdb_page_dirty(txn, np);
+	*mp = np;
+
+	return MDB_SUCCESS;
+
+fail:
+	txn->mt_flags |= MDB_TXN_ERROR;
+	return rc;
+}
+
+/** Copy the used portions of a non-overflow page.
+ * @param[in] dst page to copy into
+ * @param[in] src page to copy from
+ * @param[in] psize size of a page
+ */
+static void
+mdb_page_copy(MDB_page *dst, MDB_page *src, unsigned int psize)
+{
+	enum { Align = sizeof(pgno_t) };
+	indx_t upper = src->mp_upper, lower = src->mp_lower, unused = upper-lower;
+
+	/* If page isn't full, just copy the used portion. Adjust
+	 * alignment so memcpy may copy words instead of bytes.
+	 */
+	if ((unused &= -Align) && !IS_LEAF2(src)) {
+		upper = (upper + PAGEBASE) & -Align;
+		memcpy(dst, src, (lower + PAGEBASE + (Align-1)) & -Align);
+		memcpy((pgno_t *)((char *)dst+upper), (pgno_t *)((char *)src+upper),
+			psize - upper);
+	} else {
+		memcpy(dst, src, psize - unused);
+	}
+}
+
+/** Pull a page off the txn's spill list, if present.
+ * If a page being referenced was spilled to disk in this txn, bring
+ * it back and make it dirty/writable again.
+ * @param[in] txn the transaction handle.
+ * @param[in] mp the page being referenced. It must not be dirty.
+ * @param[out] ret the writable page, if any. ret is unchanged if
+ * mp wasn't spilled.
+ */
+static int
+mdb_page_unspill(MDB_txn *txn, MDB_page *mp, MDB_page **ret)
+{
+	MDB_env *env = txn->mt_env;
+	const MDB_txn *tx2;
+	unsigned x;
+	pgno_t pgno = mp->mp_pgno, pn = pgno << 1;
+
+	for (tx2 = txn; tx2; tx2=tx2->mt_parent) {
+		if (!tx2->mt_spill_pgs)
+			continue;
+		x = mdb_midl_search(tx2->mt_spill_pgs, pn);
+		if (x <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[x] == pn) {
+			MDB_page *np;
+			int num;
+			if (txn->mt_dirty_room == 0)
+				return MDB_TXN_FULL;
+			if (IS_OVERFLOW(mp))
+				num = mp->mp_pages;
+			else
+				num = 1;
+			if (env->me_flags & MDB_WRITEMAP) {
+				np = mp;
+			} else {
+				np = mdb_page_malloc(txn, num);
+				if (!np)
+					return ENOMEM;
+				if (num > 1)
+					memcpy(np, mp, num * env->me_psize);
+				else
+					mdb_page_copy(np, mp, env->me_psize);
+			}
+			if (tx2 == txn) {
+				/* If in current txn, this page is no longer spilled.
+				 * If it happens to be the last page, truncate the spill list.
+				 * Otherwise mark it as deleted by setting the LSB.
+				 */
+				if (x == txn->mt_spill_pgs[0])
+					txn->mt_spill_pgs[0]--;
+				else
+					txn->mt_spill_pgs[x] |= 1;
+			}	/* otherwise, if belonging to a parent txn, the
+				 * page remains spilled until child commits
+				 */
+
+			mdb_page_dirty(txn, np);
+			np->mp_flags |= P_DIRTY;
+			*ret = np;
+			break;
+		}
+	}
+	return MDB_SUCCESS;
+}
+
+/** Touch a page: make it dirty and re-insert into tree with updated pgno.
+ * @param[in] mc cursor pointing to the page to be touched
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_page_touch(MDB_cursor *mc)
+{
+	MDB_page *mp = mc->mc_pg[mc->mc_top], *np;
+	MDB_txn *txn = mc->mc_txn;
+	MDB_cursor *m2, *m3;
+	pgno_t	pgno;
+	int rc;
+
+	if (!F_ISSET(mp->mp_flags, P_DIRTY)) {
+		if (txn->mt_flags & MDB_TXN_SPILLS) {
+			np = NULL;
+			rc = mdb_page_unspill(txn, mp, &np);
+			if (rc)
+				goto fail;
+			if (np)
+				goto done;
+		}
+		if ((rc = mdb_midl_need(&txn->mt_free_pgs, 1)) ||
+			(rc = mdb_page_alloc(mc, 1, &np)))
+			goto fail;
+		pgno = np->mp_pgno;
+		DPRINTF(("touched db %d page %"Z"u -> %"Z"u", DDBI(mc),
+			mp->mp_pgno, pgno));
+		mdb_cassert(mc, mp->mp_pgno != pgno);
+		mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);
+		/* Update the parent page, if any, to point to the new page */
+		if (mc->mc_top) {
+			MDB_page *parent = mc->mc_pg[mc->mc_top-1];
+			MDB_node *node = NODEPTR(parent, mc->mc_ki[mc->mc_top-1]);
+			SETPGNO(node, pgno);
+		} else {
+			mc->mc_db->md_root = pgno;
+		}
+	} else if (txn->mt_parent && !IS_SUBP(mp)) {
+		MDB_ID2 mid, *dl = txn->mt_u.dirty_list;
+		pgno = mp->mp_pgno;
+		/* If txn has a parent, make sure the page is in our
+		 * dirty list.
+		 */
+		if (dl[0].mid) {
+			unsigned x = mdb_mid2l_search(dl, pgno);
+			if (x <= dl[0].mid && dl[x].mid == pgno) {
+				if (mp != dl[x].mptr) { /* bad cursor? */
+					mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
+					txn->mt_flags |= MDB_TXN_ERROR;
+					return MDB_CORRUPTED;
+				}
+				return 0;
+			}
+		}
+		mdb_cassert(mc, dl[0].mid < MDB_IDL_UM_MAX);
+		/* No - copy it */
+		np = mdb_page_malloc(txn, 1);
+		if (!np)
+			return ENOMEM;
+		mid.mid = pgno;
+		mid.mptr = np;
+		rc = mdb_mid2l_insert(dl, &mid);
+		mdb_cassert(mc, rc == 0);
+	} else {
+		return 0;
+	}
+
+	mdb_page_copy(np, mp, txn->mt_env->me_psize);
+	np->mp_pgno = pgno;
+	np->mp_flags |= P_DIRTY;
+
+done:
+	/* Adjust cursors pointing to mp */
+	mc->mc_pg[mc->mc_top] = np;
+	m2 = txn->mt_cursors[mc->mc_dbi];
+	if (mc->mc_flags & C_SUB) {
+		for (; m2; m2=m2->mc_next) {
+			m3 = &m2->mc_xcursor->mx_cursor;
+			if (m3->mc_snum < mc->mc_snum) continue;
+			if (m3->mc_pg[mc->mc_top] == mp)
+				m3->mc_pg[mc->mc_top] = np;
+		}
+	} else {
+		for (; m2; m2=m2->mc_next) {
+			if (m2->mc_snum < mc->mc_snum) continue;
+			if (m2->mc_pg[mc->mc_top] == mp) {
+				m2->mc_pg[mc->mc_top] = np;
+				if ((mc->mc_db->md_flags & MDB_DUPSORT) &&
+					IS_LEAF(np) &&
+					m2->mc_ki[mc->mc_top] == mc->mc_ki[mc->mc_top])
+				{
+					MDB_node *leaf = NODEPTR(np, mc->mc_ki[mc->mc_top]);
+					if (!(leaf->mn_flags & F_SUBDATA))
+						m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
+				}
+			}
+		}
+	}
+#ifdef VL32
+	{
+		MDB_ID2L rl = mc->mc_txn->mt_rpages;
+		unsigned x = mdb_mid2l_search(rl, mp->mp_pgno);
+		if (x <= rl[0].mid && rl[x].mid == mp->mp_pgno) {
+			munmap(mp, mc->mc_txn->mt_env->me_psize);
+			while (x < rl[0].mid) {
+				rl[x] = rl[x+1];
+				x++;
+			}
+			rl[0].mid--;
+		}
+	}
+#endif
+	return 0;
+
+fail:
+	txn->mt_flags |= MDB_TXN_ERROR;
+	return rc;
+}
+
+int
+mdb_env_sync(MDB_env *env, int force)
+{
+	int rc = 0;
+	if (force || !F_ISSET(env->me_flags, MDB_NOSYNC)) {
+		if (env->me_flags & MDB_WRITEMAP) {
+			int flags = ((env->me_flags & MDB_MAPASYNC) && !force)
+				? MS_ASYNC : MS_SYNC;
+			if (MDB_MSYNC(env->me_map, env->me_mapsize, flags))
+				rc = ErrCode();
+#ifdef _WIN32
+			else if (flags == MS_SYNC && MDB_FDATASYNC(env->me_fd))
+				rc = ErrCode();
+#endif
+		} else {
+			if (MDB_FDATASYNC(env->me_fd))
+				rc = ErrCode();
+		}
+	}
+	return rc;
+}
+
+/** Back up parent txn's cursors, then grab the originals for tracking */
+static int
+mdb_cursor_shadow(MDB_txn *src, MDB_txn *dst)
+{
+	MDB_cursor *mc, *bk;
+	MDB_xcursor *mx;
+	size_t size;
+	int i;
+
+	for (i = src->mt_numdbs; --i >= 0; ) {
+		if ((mc = src->mt_cursors[i]) != NULL) {
+			size = sizeof(MDB_cursor);
+			if (mc->mc_xcursor)
+				size += sizeof(MDB_xcursor);
+			for (; mc; mc = bk->mc_next) {
+				bk = malloc(size);
+				if (!bk)
+					return ENOMEM;
+				*bk = *mc;
+				mc->mc_backup = bk;
+				mc->mc_db = &dst->mt_dbs[i];
+				/* Kill pointers into src - and dst to reduce abuse: The
+				 * user may not use mc until dst ends. Otherwise we'd...
+				 */
+				mc->mc_txn    = NULL;	/* ...set this to dst */
+				mc->mc_dbflag = NULL;	/* ...and &dst->mt_dbflags[i] */
+				if ((mx = mc->mc_xcursor) != NULL) {
+					*(MDB_xcursor *)(bk+1) = *mx;
+					mx->mx_cursor.mc_txn = NULL; /* ...and dst. */
+				}
+				mc->mc_next = dst->mt_cursors[i];
+				dst->mt_cursors[i] = mc;
+			}
+		}
+	}
+	return MDB_SUCCESS;
+}
+
+/** Close this write txn's cursors, give parent txn's cursors back to parent.
+ * @param[in] txn the transaction handle.
+ * @param[in] merge true to keep changes to parent cursors, false to revert.
+ * @return 0 on success, non-zero on failure.
+ */
+static void
+mdb_cursors_close(MDB_txn *txn, unsigned merge)
+{
+	MDB_cursor **cursors = txn->mt_cursors, *mc, *next, *bk;
+	MDB_xcursor *mx;
+	int i;
+
+	for (i = txn->mt_numdbs; --i >= 0; ) {
+		for (mc = cursors[i]; mc; mc = next) {
+			next = mc->mc_next;
+			if ((bk = mc->mc_backup) != NULL) {
+				if (merge) {
+					/* Commit changes to parent txn */
+					mc->mc_next = bk->mc_next;
+					mc->mc_backup = bk->mc_backup;
+					mc->mc_txn = bk->mc_txn;
+					mc->mc_db = bk->mc_db;
+					mc->mc_dbflag = bk->mc_dbflag;
+					if ((mx = mc->mc_xcursor) != NULL)
+						mx->mx_cursor.mc_txn = bk->mc_txn;
+				} else {
+					/* Abort nested txn */
+					*mc = *bk;
+					if ((mx = mc->mc_xcursor) != NULL)
+						*mx = *(MDB_xcursor *)(bk+1);
+				}
+				mc = bk;
+			}
+			/* Only malloced cursors are permanently tracked. */
+			free(mc);
+		}
+		cursors[i] = NULL;
+	}
+}
+
+#if !(MDB_DEBUG)
+#define mdb_txn_reset0(txn, act) mdb_txn_reset0(txn)
+#endif
+static void
+mdb_txn_reset0(MDB_txn *txn, const char *act);
+
+#if !(MDB_PIDLOCK)		/* Currently the same as defined(_WIN32) */
+enum Pidlock_op {
+	Pidset, Pidcheck
+};
+#else
+enum Pidlock_op {
+	Pidset = F_SETLK, Pidcheck = F_GETLK
+};
+#endif
+
+/** Set or check a pid lock. Set returns 0 on success.
+ * Check returns 0 if the process is certainly dead, nonzero if it may
+ * be alive (the lock exists or an error happened so we do not know).
+ *
+ * On Windows Pidset is a no-op, we merely check for the existence
+ * of the process with the given pid. On POSIX we use a single byte
+ * lock on the lockfile, set at an offset equal to the pid.
+ */
+static int
+mdb_reader_pid(MDB_env *env, enum Pidlock_op op, MDB_PID_T pid)
+{
+#if !(MDB_PIDLOCK)		/* Currently the same as defined(_WIN32) */
+	int ret = 0;
+	HANDLE h;
+	if (op == Pidcheck) {
+		h = OpenProcess(env->me_pidquery, FALSE, pid);
+		/* No documented "no such process" code, but other program use this: */
+		if (!h)
+			return ErrCode() != ERROR_INVALID_PARAMETER;
+		/* A process exists until all handles to it close. Has it exited? */
+		ret = WaitForSingleObject(h, 0) != 0;
+		CloseHandle(h);
+	}
+	return ret;
+#else
+	for (;;) {
+		int rc;
+		struct flock lock_info;
+		memset(&lock_info, 0, sizeof(lock_info));
+		lock_info.l_type = F_WRLCK;
+		lock_info.l_whence = SEEK_SET;
+		lock_info.l_start = pid;
+		lock_info.l_len = 1;
+		if ((rc = fcntl(env->me_lfd, op, &lock_info)) == 0) {
+			if (op == F_GETLK && lock_info.l_type != F_UNLCK)
+				rc = -1;
+		} else if ((rc = ErrCode()) == EINTR) {
+			continue;
+		}
+		return rc;
+	}
+#endif
+}
+
+/** Common code for #mdb_txn_begin() and #mdb_txn_renew().
+ * @param[in] txn the transaction handle to initialize
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_txn_renew0(MDB_txn *txn)
+{
+	MDB_env *env = txn->mt_env;
+	MDB_txninfo *ti = env->me_txns;
+	MDB_meta *meta;
+	unsigned int i, nr;
+	uint16_t x;
+	int rc, new_notls = 0;
+
+	/* Setup db info */
+	txn->mt_numdbs = env->me_numdbs;
+	txn->mt_dbxs = env->me_dbxs;	/* mostly static anyway */
+
+	if (txn->mt_flags & MDB_TXN_RDONLY) {
+		if (!ti) {
+			meta = env->me_metas[ mdb_env_pick_meta(env) ];
+			txn->mt_txnid = meta->mm_txnid;
+			txn->mt_u.reader = NULL;
+		} else {
+			MDB_reader *r = (env->me_flags & MDB_NOTLS) ? txn->mt_u.reader :
+				pthread_getspecific(env->me_txkey);
+			if (r) {
+				if (r->mr_pid != env->me_pid || r->mr_txnid != (txnid_t)-1)
+					return MDB_BAD_RSLOT;
+			} else {
+				MDB_PID_T pid = env->me_pid;
+				MDB_THR_T tid = pthread_self();
+
+				if (!env->me_live_reader) {
+					rc = mdb_reader_pid(env, Pidset, pid);
+					if (rc)
+						return rc;
+					env->me_live_reader = 1;
+				}
+
+				LOCK_MUTEX_R(env);
+				nr = ti->mti_numreaders;
+				for (i=0; i<nr; i++)
+					if (ti->mti_readers[i].mr_pid == 0)
+						break;
+				if (i == env->me_maxreaders) {
+					UNLOCK_MUTEX_R(env);
+					return MDB_READERS_FULL;
+				}
+				ti->mti_readers[i].mr_pid = pid;
+				ti->mti_readers[i].mr_tid = tid;
+				if (i == nr)
+					ti->mti_numreaders = ++nr;
+				/* Save numreaders for un-mutexed mdb_env_close() */
+				env->me_numreaders = nr;
+				UNLOCK_MUTEX_R(env);
+
+				r = &ti->mti_readers[i];
+				new_notls = (env->me_flags & MDB_NOTLS);
+				if (!new_notls && (rc=pthread_setspecific(env->me_txkey, r))) {
+					r->mr_pid = 0;
+					return rc;
+				}
+			}
+			txn->mt_txnid = r->mr_txnid = ti->mti_txnid;
+			txn->mt_u.reader = r;
+			meta = env->me_metas[txn->mt_txnid & 1];
+		}
+	} else {
+		if (ti) {
+			LOCK_MUTEX_W(env);
+
+			txn->mt_txnid = ti->mti_txnid;
+			meta = env->me_metas[txn->mt_txnid & 1];
+		} else {
+			meta = env->me_metas[ mdb_env_pick_meta(env) ];
+			txn->mt_txnid = meta->mm_txnid;
+		}
+		txn->mt_txnid++;
+#if MDB_DEBUG
+		if (txn->mt_txnid == mdb_debug_start)
+			mdb_debug = 1;
+#endif
+		txn->mt_dirty_room = MDB_IDL_UM_MAX;
+		txn->mt_u.dirty_list = env->me_dirty_list;
+		txn->mt_u.dirty_list[0].mid = 0;
+		txn->mt_free_pgs = env->me_free_pgs;
+		txn->mt_free_pgs[0] = 0;
+		txn->mt_spill_pgs = NULL;
+		env->me_txn = txn;
+		memcpy(txn->mt_dbiseqs, env->me_dbiseqs, env->me_maxdbs * sizeof(unsigned int));
+	}
+
+	/* Copy the DB info and flags */
+	memcpy(txn->mt_dbs, meta->mm_dbs, 2 * sizeof(MDB_db));
+
+	/* Moved to here to avoid a data race in read TXNs */
+	txn->mt_next_pgno = meta->mm_last_pg+1;
+
+	for (i=2; i<txn->mt_numdbs; i++) {
+		x = env->me_dbflags[i];
+		txn->mt_dbs[i].md_flags = x & PERSISTENT_FLAGS;
+		txn->mt_dbflags[i] = (x & MDB_VALID) ? DB_VALID|DB_STALE : 0;
+	}
+	txn->mt_dbflags[0] = txn->mt_dbflags[1] = DB_VALID;
+
+	if (env->me_maxpg < txn->mt_next_pgno) {
+		mdb_txn_reset0(txn, "renew0-mapfail");
+		if (new_notls) {
+			txn->mt_u.reader->mr_pid = 0;
+			txn->mt_u.reader = NULL;
+		}
+		return MDB_MAP_RESIZED;
+	}
+
+	return MDB_SUCCESS;
+}
+
+int
+mdb_txn_renew(MDB_txn *txn)
+{
+	int rc;
+
+	if (!txn || txn->mt_dbxs)	/* A reset txn has mt_dbxs==NULL */
+		return EINVAL;
+
+	if (txn->mt_env->me_flags & MDB_FATAL_ERROR) {
+		DPUTS("environment had fatal error, must shutdown!");
+		return MDB_PANIC;
+	}
+
+	rc = mdb_txn_renew0(txn);
+	if (rc == MDB_SUCCESS) {
+		DPRINTF(("renew txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
+			txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
+			(void *)txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root));
+	}
+	return rc;
+}
+
+int
+mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
+{
+	MDB_txn *txn;
+	MDB_ntxn *ntxn;
+	int rc, size, tsize = sizeof(MDB_txn);
+
+	if (env->me_flags & MDB_FATAL_ERROR) {
+		DPUTS("environment had fatal error, must shutdown!");
+		return MDB_PANIC;
+	}
+	if ((env->me_flags & MDB_RDONLY) && !(flags & MDB_RDONLY))
+		return EACCES;
+	if (parent) {
+		/* Nested transactions: Max 1 child, write txns only, no writemap */
+		if (parent->mt_child ||
+			(flags & MDB_RDONLY) ||
+			(parent->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_ERROR)) ||
+			(env->me_flags & MDB_WRITEMAP))
+		{
+			return (parent->mt_flags & MDB_TXN_RDONLY) ? EINVAL : MDB_BAD_TXN;
+		}
+		tsize = sizeof(MDB_ntxn);
+	}
+	size = tsize + env->me_maxdbs * (sizeof(MDB_db)+1);
+	if (!(flags & MDB_RDONLY)) {
+		if (!parent) {
+			txn = env->me_txn0;
+			txn->mt_flags = 0;
+			goto ok;
+		}
+		size += env->me_maxdbs * sizeof(MDB_cursor *);
+		/* child txns use parent's dbiseqs */
+		if (!parent)
+			size += env->me_maxdbs * sizeof(unsigned int);
+	}
+
+	if ((txn = calloc(1, size)) == NULL) {
+		DPRINTF(("calloc: %s", strerror(errno)));
+		return ENOMEM;
+	}
+#ifdef VL32
+	if (!parent) {
+		txn->mt_rpages = calloc(MDB_IDL_UM_SIZE, sizeof(MDB_ID2));
+		if (!txn->mt_rpages) {
+			free(txn);
+			return ENOMEM;
+		}
+	}
+#endif
+	txn->mt_dbs = (MDB_db *) ((char *)txn + tsize);
+	if (flags & MDB_RDONLY) {
+		txn->mt_flags |= MDB_TXN_RDONLY;
+		txn->mt_dbflags = (unsigned char *)(txn->mt_dbs + env->me_maxdbs);
+		txn->mt_dbiseqs = env->me_dbiseqs;
+	} else {
+		txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
+		if (parent) {
+			txn->mt_dbiseqs = parent->mt_dbiseqs;
+			txn->mt_dbflags = (unsigned char *)(txn->mt_cursors + env->me_maxdbs);
+		} else {
+			txn->mt_dbiseqs = (unsigned int *)(txn->mt_cursors + env->me_maxdbs);
+			txn->mt_dbflags = (unsigned char *)(txn->mt_dbiseqs + env->me_maxdbs);
+		}
+	}
+	txn->mt_env = env;
+
+ok:
+	if (parent) {
+		unsigned int i;
+		txn->mt_u.dirty_list = malloc(sizeof(MDB_ID2)*MDB_IDL_UM_SIZE);
+		if (!txn->mt_u.dirty_list ||
+			!(txn->mt_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)))
+		{
+			free(txn->mt_u.dirty_list);
+			free(txn);
+			return ENOMEM;
+		}
+		txn->mt_txnid = parent->mt_txnid;
+		txn->mt_dirty_room = parent->mt_dirty_room;
+		txn->mt_u.dirty_list[0].mid = 0;
+		txn->mt_spill_pgs = NULL;
+		txn->mt_next_pgno = parent->mt_next_pgno;
+		parent->mt_child = txn;
+		txn->mt_parent = parent;
+		txn->mt_numdbs = parent->mt_numdbs;
+		txn->mt_flags = parent->mt_flags;
+		txn->mt_dbxs = parent->mt_dbxs;
+#ifdef VL32
+		txn->mt_rpages = parent->mt_rpages;
+#endif
+		memcpy(txn->mt_dbs, parent->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
+		/* Copy parent's mt_dbflags, but clear DB_NEW */
+		for (i=0; i<txn->mt_numdbs; i++)
+			txn->mt_dbflags[i] = parent->mt_dbflags[i] & ~DB_NEW;
+		rc = 0;
+		ntxn = (MDB_ntxn *)txn;
+		ntxn->mnt_pgstate = env->me_pgstate; /* save parent me_pghead & co */
+		if (env->me_pghead) {
+			size = MDB_IDL_SIZEOF(env->me_pghead);
+			env->me_pghead = mdb_midl_alloc(env->me_pghead[0]);
+			if (env->me_pghead)
+				memcpy(env->me_pghead, ntxn->mnt_pgstate.mf_pghead, size);
+			else
+				rc = ENOMEM;
+		}
+		if (!rc)
+			rc = mdb_cursor_shadow(parent, txn);
+		if (rc)
+			mdb_txn_reset0(txn, "beginchild-fail");
+	} else {
+		rc = mdb_txn_renew0(txn);
+	}
+	if (rc) {
+		if (txn != env->me_txn0)
+			free(txn);
+	} else {
+		*ret = txn;
+		DPRINTF(("begin txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
+			txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
+			(void *) txn, (void *) env, txn->mt_dbs[MAIN_DBI].md_root));
+	}
+
+	return rc;
+}
+
+MDB_env *
+mdb_txn_env(MDB_txn *txn)
+{
+	if(!txn) return NULL;
+	return txn->mt_env;
+}
+
+/** Export or close DBI handles opened in this txn. */
+static void
+mdb_dbis_update(MDB_txn *txn, int keep)
+{
+	int i;
+	MDB_dbi n = txn->mt_numdbs;
+	MDB_env *env = txn->mt_env;
+	unsigned char *tdbflags = txn->mt_dbflags;
+
+	for (i = n; --i >= 2;) {
+		if (tdbflags[i] & DB_NEW) {
+			if (keep) {
+				env->me_dbflags[i] = txn->mt_dbs[i].md_flags | MDB_VALID;
+			} else {
+				char *ptr = env->me_dbxs[i].md_name.mv_data;
+				if (ptr) {
+					env->me_dbxs[i].md_name.mv_data = NULL;
+					env->me_dbxs[i].md_name.mv_size = 0;
+					env->me_dbflags[i] = 0;
+					env->me_dbiseqs[i]++;
+					free(ptr);
+				}
+			}
+		}
+	}
+	if (keep && env->me_numdbs < n)
+		env->me_numdbs = n;
+}
+
+/** Common code for #mdb_txn_reset() and #mdb_txn_abort().
+ * May be called twice for readonly txns: First reset it, then abort.
+ * @param[in] txn the transaction handle to reset
+ * @param[in] act why the transaction is being reset
+ */
+static void
+mdb_txn_reset0(MDB_txn *txn, const char *act)
+{
+	MDB_env	*env = txn->mt_env;
+
+	/* Close any DBI handles opened in this txn */
+	mdb_dbis_update(txn, 0);
+
+	DPRINTF(("%s txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
+		act, txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
+		(void *) txn, (void *)env, txn->mt_dbs[MAIN_DBI].md_root));
+
+	if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
+		if (txn->mt_u.reader) {
+			txn->mt_u.reader->mr_txnid = (txnid_t)-1;
+			if (!(env->me_flags & MDB_NOTLS))
+				txn->mt_u.reader = NULL; /* txn does not own reader */
+		}
+		txn->mt_numdbs = 0;		/* close nothing if called again */
+		txn->mt_dbxs = NULL;	/* mark txn as reset */
+	} else {
+		mdb_cursors_close(txn, 0);
+
+		if (!(env->me_flags & MDB_WRITEMAP)) {
+			mdb_dlist_free(txn);
+		}
+		mdb_midl_free(env->me_pghead);
+
+		if (txn->mt_parent) {
+			txn->mt_parent->mt_child = NULL;
+			env->me_pgstate = ((MDB_ntxn *)txn)->mnt_pgstate;
+			mdb_midl_free(txn->mt_free_pgs);
+			mdb_midl_free(txn->mt_spill_pgs);
+			free(txn->mt_u.dirty_list);
+			return;
+		}
+
+		if (mdb_midl_shrink(&txn->mt_free_pgs))
+			env->me_free_pgs = txn->mt_free_pgs;
+		env->me_pghead = NULL;
+		env->me_pglast = 0;
+
+		env->me_txn = NULL;
+		/* The writer mutex was locked in mdb_txn_begin. */
+		if (env->me_txns)
+			UNLOCK_MUTEX_W(env);
+	}
+#ifdef VL32
+	{
+		unsigned i, n = txn->mt_rpages[0].mid;
+		for (i = 1; i <= n; i++) {
+#ifdef _WIN32
+			UnmapViewOfFile(txn->mt_rpages[i].mptr);)
+#else
+			MDB_page *mp = txn->mt_rpages[i].mptr;
+			int size = txn->mt_env->me_psize;
+			if (IS_OVERFLOW(mp)) size *= mp->mp_pages;
+			munmap(mp, size);
+#endif
+		}
+	}
+	txn->mt_rpages[0].mid = 0;
+#endif
+}
+
+void
+mdb_txn_reset(MDB_txn *txn)
+{
+	if (txn == NULL)
+		return;
+
+	/* This call is only valid for read-only txns */
+	if (!(txn->mt_flags & MDB_TXN_RDONLY))
+		return;
+
+	mdb_txn_reset0(txn, "reset");
+}
+
+void
+mdb_txn_abort(MDB_txn *txn)
+{
+	if (txn == NULL)
+		return;
+
+	if (txn->mt_child)
+		mdb_txn_abort(txn->mt_child);
+
+	mdb_txn_reset0(txn, "abort");
+	/* Free reader slot tied to this txn (if MDB_NOTLS && writable FS) */
+	if ((txn->mt_flags & MDB_TXN_RDONLY) && txn->mt_u.reader)
+		txn->mt_u.reader->mr_pid = 0;
+
+	if (txn != txn->mt_env->me_txn0) {
+#ifdef VL32
+		free(txn->mt_rpages);
+#endif
+		free(txn);
+	}
+}
+
+/** Save the freelist as of this transaction to the freeDB.
+ * This changes the freelist. Keep trying until it stabilizes.
+ */
+static int
+mdb_freelist_save(MDB_txn *txn)
+{
+	/* env->me_pghead[] can grow and shrink during this call.
+	 * env->me_pglast and txn->mt_free_pgs[] can only grow.
+	 * Page numbers cannot disappear from txn->mt_free_pgs[].
+	 */
+	MDB_cursor mc;
+	MDB_env	*env = txn->mt_env;
+	int rc, maxfree_1pg = env->me_maxfree_1pg, more = 1;
+	txnid_t	pglast = 0, head_id = 0;
+	pgno_t	freecnt = 0, *free_pgs, *mop;
+	ssize_t	head_room = 0, total_room = 0, mop_len, clean_limit;
+
+	mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
+
+	if (env->me_pghead) {
+		/* Make sure first page of freeDB is touched and on freelist */
+		rc = mdb_page_search(&mc, NULL, MDB_PS_FIRST|MDB_PS_MODIFY);
+		if (rc && rc != MDB_NOTFOUND)
+			return rc;
+	}
+
+	if (!env->me_pghead && txn->mt_loose_pgs) {
+		/* Put loose page numbers in mt_free_pgs, since
+		 * we may be unable to return them to me_pghead.
+		 */
+		MDB_page *mp = txn->mt_loose_pgs;
+		if ((rc = mdb_midl_need(&txn->mt_free_pgs, txn->mt_loose_count)) != 0)
+			return rc;
+		for (; mp; mp = NEXT_LOOSE_PAGE(mp))
+			mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);
+		txn->mt_loose_pgs = NULL;
+		txn->mt_loose_count = 0;
+	}
+
+	/* MDB_RESERVE cancels meminit in ovpage malloc (when no WRITEMAP) */
+	clean_limit = (env->me_flags & (MDB_NOMEMINIT|MDB_WRITEMAP))
+		? SSIZE_MAX : maxfree_1pg;
+
+	for (;;) {
+		/* Come back here after each Put() in case freelist changed */
+		MDB_val key, data;
+		pgno_t *pgs;
+		ssize_t j;
+
+		/* If using records from freeDB which we have not yet
+		 * deleted, delete them and any we reserved for me_pghead.
+		 */
+		while (pglast < env->me_pglast) {
+			rc = mdb_cursor_first(&mc, &key, NULL);
+			if (rc)
+				return rc;
+			pglast = head_id = *(txnid_t *)key.mv_data;
+			total_room = head_room = 0;
+			mdb_tassert(txn, pglast <= env->me_pglast);
+			rc = mdb_cursor_del(&mc, 0);
+			if (rc)
+				return rc;
+		}
+
+		/* Save the IDL of pages freed by this txn, to a single record */
+		if (freecnt < txn->mt_free_pgs[0]) {
+			if (!freecnt) {
+				/* Make sure last page of freeDB is touched and on freelist */
+				rc = mdb_page_search(&mc, NULL, MDB_PS_LAST|MDB_PS_MODIFY);
+				if (rc && rc != MDB_NOTFOUND)
+					return rc;
+			}
+			free_pgs = txn->mt_free_pgs;
+			/* Write to last page of freeDB */
+			key.mv_size = sizeof(txn->mt_txnid);
+			key.mv_data = &txn->mt_txnid;
+			do {
+				freecnt = free_pgs[0];
+				data.mv_size = MDB_IDL_SIZEOF(free_pgs);
+				rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
+				if (rc)
+					return rc;
+				/* Retry if mt_free_pgs[] grew during the Put() */
+				free_pgs = txn->mt_free_pgs;
+			} while (freecnt < free_pgs[0]);
+			mdb_midl_sort(free_pgs);
+			memcpy(data.mv_data, free_pgs, data.mv_size);
+#if (MDB_DEBUG) > 1
+			{
+				unsigned int i = free_pgs[0];
+				DPRINTF(("IDL write txn %"Z"u root %"Z"u num %u",
+					txn->mt_txnid, txn->mt_dbs[FREE_DBI].md_root, i));
+				for (; i; i--)
+					DPRINTF(("IDL %"Z"u", free_pgs[i]));
+			}
+#endif
+			continue;
+		}
+
+		mop = env->me_pghead;
+		mop_len = (mop ? mop[0] : 0) + txn->mt_loose_count;
+
+		/* Reserve records for me_pghead[]. Split it if multi-page,
+		 * to avoid searching freeDB for a page range. Use keys in
+		 * range [1,me_pglast]: Smaller than txnid of oldest reader.
+		 */
+		if (total_room >= mop_len) {
+			if (total_room == mop_len || --more < 0)
+				break;
+		} else if (head_room >= maxfree_1pg && head_id > 1) {
+			/* Keep current record (overflow page), add a new one */
+			head_id--;
+			head_room = 0;
+		}
+		/* (Re)write {key = head_id, IDL length = head_room} */
+		total_room -= head_room;
+		head_room = mop_len - total_room;
+		if (head_room > maxfree_1pg && head_id > 1) {
+			/* Overflow multi-page for part of me_pghead */
+			head_room /= head_id; /* amortize page sizes */
+			head_room += maxfree_1pg - head_room % (maxfree_1pg + 1);
+		} else if (head_room < 0) {
+			/* Rare case, not bothering to delete this record */
+			head_room = 0;
+		}
+		key.mv_size = sizeof(head_id);
+		key.mv_data = &head_id;
+		data.mv_size = (head_room + 1) * sizeof(pgno_t);
+		rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
+		if (rc)
+			return rc;
+		/* IDL is initially empty, zero out at least the length */
+		pgs = (pgno_t *)data.mv_data;
+		j = head_room > clean_limit ? head_room : 0;
+		do {
+			pgs[j] = 0;
+		} while (--j >= 0);
+		total_room += head_room;
+	}
+
+	/* Return loose page numbers to me_pghead, though usually none are
+	 * left at this point.  The pages themselves remain in dirty_list.
+	 */
+	if (txn->mt_loose_pgs) {
+		MDB_page *mp = txn->mt_loose_pgs;
+		unsigned count = txn->mt_loose_count;
+		MDB_IDL loose;
+		/* Room for loose pages + temp IDL with same */
+		if ((rc = mdb_midl_need(&env->me_pghead, 2*count+1)) != 0)
+			return rc;
+		mop = env->me_pghead;
+		loose = mop + MDB_IDL_ALLOCLEN(mop) - count;
+		for (count = 0; mp; mp = NEXT_LOOSE_PAGE(mp))
+			loose[ ++count ] = mp->mp_pgno;
+		loose[0] = count;
+		mdb_midl_sort(loose);
+		mdb_midl_xmerge(mop, loose);
+		txn->mt_loose_pgs = NULL;
+		txn->mt_loose_count = 0;
+		mop_len = mop[0];
+	}
+
+	/* Fill in the reserved me_pghead records */
+	rc = MDB_SUCCESS;
+	if (mop_len) {
+		MDB_val key, data;
+
+		mop += mop_len;
+		rc = mdb_cursor_first(&mc, &key, &data);
+		for (; !rc; rc = mdb_cursor_next(&mc, &key, &data, MDB_NEXT)) {
+			txnid_t id = *(txnid_t *)key.mv_data;
+			ssize_t	len = (ssize_t)(data.mv_size / sizeof(MDB_ID)) - 1;
+			MDB_ID save;
+
+			mdb_tassert(txn, len >= 0 && id <= env->me_pglast);
+			key.mv_data = &id;
+			if (len > mop_len) {
+				len = mop_len;
+				data.mv_size = (len + 1) * sizeof(MDB_ID);
+			}
+			data.mv_data = mop -= len;
+			save = mop[0];
+			mop[0] = len;
+			rc = mdb_cursor_put(&mc, &key, &data, MDB_CURRENT);
+			mop[0] = save;
+			if (rc || !(mop_len -= len))
+				break;
+		}
+	}
+	return rc;
+}
+
+/** Flush (some) dirty pages to the map, after clearing their dirty flag.
+ * @param[in] txn the transaction that's being committed
+ * @param[in] keep number of initial pages in dirty_list to keep dirty.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_page_flush(MDB_txn *txn, int keep)
+{
+	MDB_env		*env = txn->mt_env;
+	MDB_ID2L	dl = txn->mt_u.dirty_list;
+	unsigned	psize = env->me_psize, j;
+	int			i, pagecount = dl[0].mid, rc;
+	size_t		size = 0, pos = 0;
+	pgno_t		pgno = 0;
+	MDB_page	*dp = NULL;
+#ifdef _WIN32
+	OVERLAPPED	ov;
+#else
+	struct iovec iov[MDB_COMMIT_PAGES];
+	ssize_t		wpos = 0, wsize = 0, wres;
+	size_t		next_pos = 1; /* impossible pos, so pos != next_pos */
+	int			n = 0;
+#endif
+
+	j = i = keep;
+
+	if (env->me_flags & MDB_WRITEMAP) {
+		/* Clear dirty flags */
+		while (++i <= pagecount) {
+			dp = dl[i].mptr;
+			/* Don't flush this page yet */
+			if (dp->mp_flags & (P_LOOSE|P_KEEP)) {
+				dp->mp_flags &= ~P_KEEP;
+				dl[++j] = dl[i];
+				continue;
+			}
+			dp->mp_flags &= ~P_DIRTY;
+		}
+		goto done;
+	}
+
+	/* Write the pages */
+	for (;;) {
+		if (++i <= pagecount) {
+			dp = dl[i].mptr;
+			/* Don't flush this page yet */
+			if (dp->mp_flags & (P_LOOSE|P_KEEP)) {
+				dp->mp_flags &= ~P_KEEP;
+				dl[i].mid = 0;
+				continue;
+			}
+			pgno = dl[i].mid;
+			/* clear dirty flag */
+			dp->mp_flags &= ~P_DIRTY;
+			pos = pgno * psize;
+			size = psize;
+			if (IS_OVERFLOW(dp)) size *= dp->mp_pages;
+		}
+#ifdef _WIN32
+		else break;
+
+		/* Windows actually supports scatter/gather I/O, but only on
+		 * unbuffered file handles. Since we're relying on the OS page
+		 * cache for all our data, that's self-defeating. So we just
+		 * write pages one at a time. We use the ov structure to set
+		 * the write offset, to at least save the overhead of a Seek
+		 * system call.
+		 */
+		DPRINTF(("committing page %"Z"u", pgno));
+		memset(&ov, 0, sizeof(ov));
+		ov.Offset = pos & 0xffffffff;
+		ov.OffsetHigh = pos >> 16 >> 16;
+		if (!WriteFile(env->me_fd, dp, size, NULL, &ov)) {
+			rc = ErrCode();
+			DPRINTF(("WriteFile: %d", rc));
+			return rc;
+		}
+#else
+		/* Write up to MDB_COMMIT_PAGES dirty pages at a time. */
+		if (pos!=next_pos || n==MDB_COMMIT_PAGES || wsize+size>MAX_WRITE) {
+			if (n) {
+				/* Write previous page(s) */
+#ifdef MDB_USE_PWRITEV
+				wres = pwritev(env->me_fd, iov, n, wpos);
+#else
+				if (n == 1) {
+					wres = pwrite(env->me_fd, iov[0].iov_base, wsize, wpos);
+				} else {
+					if (lseek(env->me_fd, wpos, SEEK_SET) == -1) {
+						rc = ErrCode();
+						DPRINTF(("lseek: %s", strerror(rc)));
+						return rc;
+					}
+					wres = writev(env->me_fd, iov, n);
+				}
+#endif
+				if (wres != wsize) {
+					if (wres < 0) {
+						rc = ErrCode();
+						DPRINTF(("Write error: %s", strerror(rc)));
+					} else {
+						rc = EIO; /* TODO: Use which error code? */
+						DPUTS("short write, filesystem full?");
+					}
+					return rc;
+				}
+				n = 0;
+			}
+			if (i > pagecount)
+				break;
+			wpos = pos;
+			wsize = 0;
+		}
+		DPRINTF(("committing page %"Z"u", pgno));
+		next_pos = pos + size;
+		iov[n].iov_len = size;
+		iov[n].iov_base = (char *)dp;
+		wsize += size;
+		n++;
+#endif	/* _WIN32 */
+	}
+
+	/* MIPS has cache coherency issues, this is a no-op everywhere else
+	 * Note: for any size >= on-chip cache size, entire on-chip cache is
+	 * flushed.
+	 */
+	CACHEFLUSH(env->me_map, txn->mt_next_pgno * env->me_psize, DCACHE);
+
+	for (i = keep; ++i <= pagecount; ) {
+		dp = dl[i].mptr;
+		/* This is a page we skipped above */
+		if (!dl[i].mid) {
+			dl[++j] = dl[i];
+			dl[j].mid = dp->mp_pgno;
+			continue;
+		}
+		mdb_dpage_free(env, dp);
+	}
+
+done:
+	i--;
+	txn->mt_dirty_room += i - j;
+	dl[0].mid = j;
+	return MDB_SUCCESS;
+}
+
+int
+mdb_txn_commit(MDB_txn *txn)
+{
+	int		rc;
+	unsigned int i;
+	MDB_env	*env;
+
+	if (txn == NULL || txn->mt_env == NULL)
+		return EINVAL;
+
+	if (txn->mt_child) {
+		rc = mdb_txn_commit(txn->mt_child);
+		txn->mt_child = NULL;
+		if (rc)
+			goto fail;
+	}
+
+	env = txn->mt_env;
+
+	if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
+		mdb_dbis_update(txn, 1);
+		txn->mt_numdbs = 2; /* so txn_abort() doesn't close any new handles */
+		mdb_txn_abort(txn);
+		return MDB_SUCCESS;
+	}
+
+	if (F_ISSET(txn->mt_flags, MDB_TXN_ERROR)) {
+		DPUTS("error flag is set, can't commit");
+		if (txn->mt_parent)
+			txn->mt_parent->mt_flags |= MDB_TXN_ERROR;
+		rc = MDB_BAD_TXN;
+		goto fail;
+	}
+
+	if (txn->mt_parent) {
+		MDB_txn *parent = txn->mt_parent;
+		MDB_page **lp;
+		MDB_ID2L dst, src;
+		MDB_IDL pspill;
+		unsigned x, y, len, ps_len;
+
+		/* Append our free list to parent's */
+		rc = mdb_midl_append_list(&parent->mt_free_pgs, txn->mt_free_pgs);
+		if (rc)
+			goto fail;
+		mdb_midl_free(txn->mt_free_pgs);
+		/* Failures after this must either undo the changes
+		 * to the parent or set MDB_TXN_ERROR in the parent.
+		 */
+
+		parent->mt_next_pgno = txn->mt_next_pgno;
+		parent->mt_flags = txn->mt_flags;
+
+		/* Merge our cursors into parent's and close them */
+		mdb_cursors_close(txn, 1);
+
+		/* Update parent's DB table. */
+		memcpy(parent->mt_dbs, txn->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
+		parent->mt_numdbs = txn->mt_numdbs;
+		parent->mt_dbflags[0] = txn->mt_dbflags[0];
+		parent->mt_dbflags[1] = txn->mt_dbflags[1];
+		for (i=2; i<txn->mt_numdbs; i++) {
+			/* preserve parent's DB_NEW status */
+			x = parent->mt_dbflags[i] & DB_NEW;
+			parent->mt_dbflags[i] = txn->mt_dbflags[i] | x;
+		}
+
+		dst = parent->mt_u.dirty_list;
+		src = txn->mt_u.dirty_list;
+		/* Remove anything in our dirty list from parent's spill list */
+		if ((pspill = parent->mt_spill_pgs) && (ps_len = pspill[0])) {
+			x = y = ps_len;
+			pspill[0] = (pgno_t)-1;
+			/* Mark our dirty pages as deleted in parent spill list */
+			for (i=0, len=src[0].mid; ++i <= len; ) {
+				MDB_ID pn = src[i].mid << 1;
+				while (pn > pspill[x])
+					x--;
+				if (pn == pspill[x]) {
+					pspill[x] = 1;
+					y = --x;
+				}
+			}
+			/* Squash deleted pagenums if we deleted any */
+			for (x=y; ++x <= ps_len; )
+				if (!(pspill[x] & 1))
+					pspill[++y] = pspill[x];
+			pspill[0] = y;
+		}
+
+		/* Find len = length of merging our dirty list with parent's */
+		x = dst[0].mid;
+		dst[0].mid = 0;		/* simplify loops */
+		if (parent->mt_parent) {
+			len = x + src[0].mid;
+			y = mdb_mid2l_search(src, dst[x].mid + 1) - 1;
+			for (i = x; y && i; y--) {
+				pgno_t yp = src[y].mid;
+				while (yp < dst[i].mid)
+					i--;
+				if (yp == dst[i].mid) {
+					i--;
+					len--;
+				}
+			}
+		} else { /* Simplify the above for single-ancestor case */
+			len = MDB_IDL_UM_MAX - txn->mt_dirty_room;
+		}
+		/* Merge our dirty list with parent's */
+		y = src[0].mid;
+		for (i = len; y; dst[i--] = src[y--]) {
+			pgno_t yp = src[y].mid;
+			while (yp < dst[x].mid)
+				dst[i--] = dst[x--];
+			if (yp == dst[x].mid)
+				free(dst[x--].mptr);
+		}
+		mdb_tassert(txn, i == x);
+		dst[0].mid = len;
+		free(txn->mt_u.dirty_list);
+		parent->mt_dirty_room = txn->mt_dirty_room;
+		if (txn->mt_spill_pgs) {
+			if (parent->mt_spill_pgs) {
+				/* TODO: Prevent failure here, so parent does not fail */
+				rc = mdb_midl_append_list(&parent->mt_spill_pgs, txn->mt_spill_pgs);
+				if (rc)
+					parent->mt_flags |= MDB_TXN_ERROR;
+				mdb_midl_free(txn->mt_spill_pgs);
+				mdb_midl_sort(parent->mt_spill_pgs);
+			} else {
+				parent->mt_spill_pgs = txn->mt_spill_pgs;
+			}
+		}
+
+		/* Append our loose page list to parent's */
+		for (lp = &parent->mt_loose_pgs; *lp; lp = &NEXT_LOOSE_PAGE(lp))
+			;
+		*lp = txn->mt_loose_pgs;
+		parent->mt_loose_count += txn->mt_loose_count;
+
+		parent->mt_child = NULL;
+		mdb_midl_free(((MDB_ntxn *)txn)->mnt_pgstate.mf_pghead);
+		free(txn);
+		return rc;
+	}
+
+	if (txn != env->me_txn) {
+		DPUTS("attempt to commit unknown transaction");
+		rc = EINVAL;
+		goto fail;
+	}
+
+	mdb_cursors_close(txn, 0);
+
+	if (!txn->mt_u.dirty_list[0].mid &&
+		!(txn->mt_flags & (MDB_TXN_DIRTY|MDB_TXN_SPILLS)))
+		goto done;
+
+	DPRINTF(("committing txn %"Z"u %p on mdbenv %p, root page %"Z"u",
+	    txn->mt_txnid, (void*)txn, (void*)env, txn->mt_dbs[MAIN_DBI].md_root));
+
+	/* Update DB root pointers */
+	if (txn->mt_numdbs > 2) {
+		MDB_cursor mc;
+		MDB_dbi i;
+		MDB_val data;
+		data.mv_size = sizeof(MDB_db);
+
+		mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
+		for (i = 2; i < txn->mt_numdbs; i++) {
+			if (txn->mt_dbflags[i] & DB_DIRTY) {
+				if (TXN_DBI_CHANGED(txn, i)) {
+					rc = MDB_BAD_DBI;
+					goto fail;
+				}
+				data.mv_data = &txn->mt_dbs[i];
+				rc = mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data, 0);
+				if (rc)
+					goto fail;
+			}
+		}
+	}
+
+	rc = mdb_freelist_save(txn);
+	if (rc)
+		goto fail;
+
+	mdb_midl_free(env->me_pghead);
+	env->me_pghead = NULL;
+	if (mdb_midl_shrink(&txn->mt_free_pgs))
+		env->me_free_pgs = txn->mt_free_pgs;
+
+#if (MDB_DEBUG) > 2
+	mdb_audit(txn);
+#endif
+
+	if ((rc = mdb_page_flush(txn, 0)) ||
+		(rc = mdb_env_sync(env, 0)) ||
+		(rc = mdb_env_write_meta(txn)))
+		goto fail;
+
+	/* Free P_LOOSE pages left behind in dirty_list */
+	if (!(env->me_flags & MDB_WRITEMAP))
+		mdb_dlist_free(txn);
+
+done:
+	env->me_pglast = 0;
+	env->me_txn = NULL;
+	mdb_dbis_update(txn, 1);
+
+	if (env->me_txns)
+		UNLOCK_MUTEX_W(env);
+	if (txn != env->me_txn0)
+		free(txn);
+
+	return MDB_SUCCESS;
+
+fail:
+	mdb_txn_abort(txn);
+	return rc;
+}
+
+/** Read the environment parameters of a DB environment before
+ * mapping it into memory.
+ * @param[in] env the environment handle
+ * @param[out] meta address of where to store the meta information
+ * @return 0 on success, non-zero on failure.
+ */
+static int ESECT
+mdb_env_read_header(MDB_env *env, MDB_meta *meta)
+{
+	MDB_metabuf	pbuf;
+	MDB_page	*p;
+	MDB_meta	*m;
+	int			i, rc, off;
+	enum { Size = sizeof(pbuf) };
+
+	/* We don't know the page size yet, so use a minimum value.
+	 * Read both meta pages so we can use the latest one.
+	 */
+
+	for (i=off=0; i<2; i++, off = meta->mm_psize) {
+#ifdef _WIN32
+		DWORD len;
+		OVERLAPPED ov;
+		memset(&ov, 0, sizeof(ov));
+		ov.Offset = off;
+		rc = ReadFile(env->me_fd, &pbuf, Size, &len, &ov) ? (int)len : -1;
+		if (rc == -1 && ErrCode() == ERROR_HANDLE_EOF)
+			rc = 0;
+#else
+		rc = pread(env->me_fd, &pbuf, Size, off);
+#endif
+		if (rc != Size) {
+			if (rc == 0 && off == 0)
+				return ENOENT;
+			rc = rc < 0 ? (int) ErrCode() : MDB_INVALID;
+			DPRINTF(("read: %s", mdb_strerror(rc)));
+			return rc;
+		}
+
+		p = (MDB_page *)&pbuf;
+
+		if (!F_ISSET(p->mp_flags, P_META)) {
+			DPRINTF(("page %"Z"u not a meta page", p->mp_pgno));
+			return MDB_INVALID;
+		}
+
+		m = METADATA(p);
+		if (m->mm_magic != MDB_MAGIC) {
+			DPUTS("meta has invalid magic");
+			return MDB_INVALID;
+		}
+
+		if (m->mm_version != MDB_DATA_VERSION) {
+			DPRINTF(("database is version %u, expected version %u",
+				m->mm_version, MDB_DATA_VERSION));
+			return MDB_VERSION_MISMATCH;
+		}
+
+		if (off == 0 || m->mm_txnid > meta->mm_txnid)
+			*meta = *m;
+	}
+	return 0;
+}
+
+static void ESECT
+mdb_env_init_meta0(MDB_env *env, MDB_meta *meta)
+{
+	meta->mm_magic = MDB_MAGIC;
+	meta->mm_version = MDB_DATA_VERSION;
+	meta->mm_mapsize = env->me_mapsize;
+	meta->mm_psize = env->me_psize;
+	meta->mm_last_pg = 1;
+	meta->mm_flags = env->me_flags & 0xffff;
+	meta->mm_flags |= MDB_INTEGERKEY;
+	meta->mm_dbs[0].md_root = P_INVALID;
+	meta->mm_dbs[1].md_root = P_INVALID;
+}
+
+/** Write the environment parameters of a freshly created DB environment.
+ * @param[in] env the environment handle
+ * @param[out] meta address of where to store the meta information
+ * @return 0 on success, non-zero on failure.
+ */
+static int ESECT
+mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
+{
+	MDB_page *p, *q;
+	int rc;
+	unsigned int	 psize;
+#ifdef _WIN32
+	DWORD len;
+	OVERLAPPED ov;
+	memset(&ov, 0, sizeof(ov));
+#define DO_PWRITE(rc, fd, ptr, size, len, pos)	do { \
+	ov.Offset = pos;	\
+	rc = WriteFile(fd, ptr, size, &len, &ov);	} while(0)
+#else
+	int len;
+#define DO_PWRITE(rc, fd, ptr, size, len, pos)	do { \
+	len = pwrite(fd, ptr, size, pos);	\
+	rc = (len >= 0); } while(0)
+#endif
+
+	DPUTS("writing new meta page");
+
+	psize = env->me_psize;
+
+	mdb_env_init_meta0(env, meta);
+
+	p = calloc(2, psize);
+	p->mp_pgno = 0;
+	p->mp_flags = P_META;
+	*(MDB_meta *)METADATA(p) = *meta;
+
+	q = (MDB_page *)((char *)p + psize);
+	q->mp_pgno = 1;
+	q->mp_flags = P_META;
+	*(MDB_meta *)METADATA(q) = *meta;
+
+	DO_PWRITE(rc, env->me_fd, p, psize * 2, len, 0);
+	if (!rc)
+		rc = ErrCode();
+	else if ((unsigned) len == psize * 2)
+		rc = MDB_SUCCESS;
+	else
+		rc = ENOSPC;
+	free(p);
+	return rc;
+}
+
+/** Update the environment info to commit a transaction.
+ * @param[in] txn the transaction that's being committed
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_env_write_meta(MDB_txn *txn)
+{
+	MDB_env *env;
+	MDB_meta	meta, metab, *mp;
+	size_t mapsize;
+	off_t off;
+	int rc, len, toggle;
+	char *ptr;
+	HANDLE mfd;
+#ifdef _WIN32
+	OVERLAPPED ov;
+#else
+	int r2;
+#endif
+
+	toggle = txn->mt_txnid & 1;
+	DPRINTF(("writing meta page %d for root page %"Z"u",
+		toggle, txn->mt_dbs[MAIN_DBI].md_root));
+
+	env = txn->mt_env;
+	mp = env->me_metas[toggle];
+	mapsize = env->me_metas[toggle ^ 1]->mm_mapsize;
+	/* Persist any increases of mapsize config */
+	if (mapsize < env->me_mapsize)
+		mapsize = env->me_mapsize;
+
+	if (env->me_flags & MDB_WRITEMAP) {
+		mp->mm_mapsize = mapsize;
+		mp->mm_dbs[0] = txn->mt_dbs[0];
+		mp->mm_dbs[1] = txn->mt_dbs[1];
+		mp->mm_last_pg = txn->mt_next_pgno - 1;
+		mp->mm_txnid = txn->mt_txnid;
+		if (!(env->me_flags & (MDB_NOMETASYNC|MDB_NOSYNC))) {
+			unsigned meta_size = env->me_psize;
+			rc = (env->me_flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC;
+			ptr = env->me_map;
+			if (toggle) {
+#ifndef _WIN32	/* POSIX msync() requires ptr = start of OS page */
+				if (meta_size < env->me_os_psize)
+					meta_size += meta_size;
+				else
+#endif
+					ptr += meta_size;
+			}
+			if (MDB_MSYNC(ptr, meta_size, rc)) {
+				rc = ErrCode();
+				goto fail;
+			}
+		}
+		goto done;
+	}
+	metab.mm_txnid = env->me_metas[toggle]->mm_txnid;
+	metab.mm_last_pg = env->me_metas[toggle]->mm_last_pg;
+
+	meta.mm_mapsize = mapsize;
+	meta.mm_dbs[0] = txn->mt_dbs[0];
+	meta.mm_dbs[1] = txn->mt_dbs[1];
+	meta.mm_last_pg = txn->mt_next_pgno - 1;
+	meta.mm_txnid = txn->mt_txnid;
+
+	off = offsetof(MDB_meta, mm_mapsize);
+	ptr = (char *)&meta + off;
+	len = sizeof(MDB_meta) - off;
+	if (toggle)
+		off += env->me_psize;
+	off += PAGEHDRSZ;
+
+	/* Write to the SYNC fd */
+	mfd = env->me_flags & (MDB_NOSYNC|MDB_NOMETASYNC) ?
+		env->me_fd : env->me_mfd;
+#ifdef _WIN32
+	{
+		memset(&ov, 0, sizeof(ov));
+		ov.Offset = off;
+		if (!WriteFile(mfd, ptr, len, (DWORD *)&rc, &ov))
+			rc = -1;
+	}
+#else
+	rc = pwrite(mfd, ptr, len, off);
+#endif
+	if (rc != len) {
+		rc = rc < 0 ? ErrCode() : EIO;
+		DPUTS("write failed, disk error?");
+		/* On a failure, the pagecache still contains the new data.
+		 * Write some old data back, to prevent it from being used.
+		 * Use the non-SYNC fd; we know it will fail anyway.
+		 */
+		meta.mm_last_pg = metab.mm_last_pg;
+		meta.mm_txnid = metab.mm_txnid;
+#ifdef _WIN32
+		memset(&ov, 0, sizeof(ov));
+		ov.Offset = off;
+		WriteFile(env->me_fd, ptr, len, NULL, &ov);
+#else
+		r2 = pwrite(env->me_fd, ptr, len, off);
+		(void)r2;	/* Silence warnings. We don't care about pwrite's return value */
+#endif
+fail:
+		env->me_flags |= MDB_FATAL_ERROR;
+		return rc;
+	}
+	/* MIPS has cache coherency issues, this is a no-op everywhere else */
+	CACHEFLUSH(env->me_map + off, len, DCACHE);
+done:
+	/* Memory ordering issues are irrelevant; since the entire writer
+	 * is wrapped by wmutex, all of these changes will become visible
+	 * after the wmutex is unlocked. Since the DB is multi-version,
+	 * readers will get consistent data regardless of how fresh or
+	 * how stale their view of these values is.
+	 */
+	if (env->me_txns)
+		env->me_txns->mti_txnid = txn->mt_txnid;
+
+	return MDB_SUCCESS;
+}
+
+/** Check both meta pages to see which one is newer.
+ * @param[in] env the environment handle
+ * @return meta toggle (0 or 1).
+ */
+static int
+mdb_env_pick_meta(const MDB_env *env)
+{
+	return (env->me_metas[0]->mm_txnid < env->me_metas[1]->mm_txnid);
+}
+
+int ESECT
+mdb_env_create(MDB_env **env)
+{
+	MDB_env *e;
+
+	e = calloc(1, sizeof(MDB_env));
+	if (!e)
+		return ENOMEM;
+
+	e->me_maxreaders = DEFAULT_READERS;
+	e->me_maxdbs = e->me_numdbs = 2;
+	e->me_fd = INVALID_HANDLE_VALUE;
+	e->me_lfd = INVALID_HANDLE_VALUE;
+	e->me_mfd = INVALID_HANDLE_VALUE;
+#ifdef MDB_USE_POSIX_SEM
+	e->me_rmutex = SEM_FAILED;
+	e->me_wmutex = SEM_FAILED;
+#endif
+	e->me_pid = getpid();
+	GET_PAGESIZE(e->me_os_psize);
+	VGMEMP_CREATE(e,0,0);
+	*env = e;
+	return MDB_SUCCESS;
+}
+
+static int ESECT
+mdb_env_map(MDB_env *env, void *addr)
+{
+	MDB_page *p;
+	unsigned int flags = env->me_flags;
+#ifdef _WIN32
+	int rc;
+	HANDLE mh;
+	LONG sizelo, sizehi;
+	size_t msize;
+
+	if (flags & MDB_RDONLY) {
+		/* Don't set explicit map size, use whatever exists */
+		msize = 0;
+		sizelo = 0;
+		sizehi = 0;
+	} else {
+		msize = env->me_mapsize;
+		sizelo = msize & 0xffffffff;
+		sizehi = msize >> 16 >> 16; /* only needed on Win64 */
+
+		/* Windows won't create mappings for zero length files.
+		 * and won't map more than the file size.
+		 * Just set the maxsize right now.
+		 */
+		if (SetFilePointer(env->me_fd, sizelo, &sizehi, 0) != (DWORD)sizelo
+			|| !SetEndOfFile(env->me_fd)
+			|| SetFilePointer(env->me_fd, 0, NULL, 0) != 0)
+			return ErrCode();
+	}
+
+	mh = CreateFileMapping(env->me_fd, NULL, flags & MDB_WRITEMAP ?
+		PAGE_READWRITE : PAGE_READONLY,
+		sizehi, sizelo, NULL);
+	if (!mh)
+		return ErrCode();
+#ifdef VL32
+	msize = 2 * env->me_psize;
+#endif
+	env->me_map = MapViewOfFileEx(mh, flags & MDB_WRITEMAP ?
+		FILE_MAP_WRITE : FILE_MAP_READ,
+		0, 0, msize, addr);
+	rc = env->me_map ? 0 : ErrCode();
+#ifdef VL32
+	env->me_fmh = mh;
+#else
+	CloseHandle(mh);
+#endif
+	if (rc)
+		return rc;
+#else
+#ifdef VL32
+	(void) flags;
+	env->me_map = mmap(addr, 2 * env->me_psize, PROT_READ, MAP_SHARED,
+		env->me_fd, 0);
+	if (env->me_map == MAP_FAILED) {
+		env->me_map = NULL;
+		return ErrCode();
+	}
+#else
+	int prot = PROT_READ;
+	if (flags & MDB_WRITEMAP) {
+		prot |= PROT_WRITE;
+		if (ftruncate(env->me_fd, env->me_mapsize) < 0)
+			return ErrCode();
+	}
+	env->me_map = mmap(addr, env->me_mapsize, prot, MAP_SHARED,
+		env->me_fd, 0);
+	if (env->me_map == MAP_FAILED) {
+		env->me_map = NULL;
+		return ErrCode();
+	}
+
+	if (flags & MDB_NORDAHEAD) {
+		/* Turn off readahead. It's harmful when the DB is larger than RAM. */
+#ifdef MADV_RANDOM
+		madvise(env->me_map, env->me_mapsize, MADV_RANDOM);
+#else
+#ifdef POSIX_MADV_RANDOM
+		posix_madvise(env->me_map, env->me_mapsize, POSIX_MADV_RANDOM);
+#endif /* POSIX_MADV_RANDOM */
+#endif /* MADV_RANDOM */
+	}
+#endif /* _WIN32 */
+
+	/* Can happen because the address argument to mmap() is just a
+	 * hint.  mmap() can pick another, e.g. if the range is in use.
+	 * The MAP_FIXED flag would prevent that, but then mmap could
+	 * instead unmap existing pages to make room for the new map.
+	 */
+	if (addr && env->me_map != addr)
+		return EBUSY;	/* TODO: Make a new MDB_* error code? */
+#endif
+
+	p = (MDB_page *)env->me_map;
+	env->me_metas[0] = METADATA(p);
+	env->me_metas[1] = (MDB_meta *)((char *)env->me_metas[0] + env->me_psize);
+
+	return MDB_SUCCESS;
+}
+
+int ESECT
+mdb_env_set_mapsize(MDB_env *env, size_t size)
+{
+	/* If env is already open, caller is responsible for making
+	 * sure there are no active txns.
+	 */
+	if (env->me_map) {
+		int rc;
+		void *old;
+		if (env->me_txn)
+			return EINVAL;
+		if (!size)
+			size = env->me_metas[mdb_env_pick_meta(env)]->mm_mapsize;
+		else if (size < env->me_mapsize) {
+			/* If the configured size is smaller, make sure it's
+			 * still big enough. Silently round up to minimum if not.
+			 */
+			size_t minsize = (env->me_metas[mdb_env_pick_meta(env)]->mm_last_pg + 1) * env->me_psize;
+			if (size < minsize)
+				size = minsize;
+		}
+		munmap(env->me_map, env->me_mapsize);
+		env->me_mapsize = size;
+		old = (env->me_flags & MDB_FIXEDMAP) ? env->me_map : NULL;
+		rc = mdb_env_map(env, old);
+		if (rc)
+			return rc;
+	}
+	env->me_mapsize = size;
+	if (env->me_psize)
+		env->me_maxpg = env->me_mapsize / env->me_psize;
+	return MDB_SUCCESS;
+}
+
+int ESECT
+mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs)
+{
+	if (env->me_map)
+		return EINVAL;
+	env->me_maxdbs = dbs + 2; /* Named databases + main and free DB */
+	return MDB_SUCCESS;
+}
+
+int ESECT
+mdb_env_set_maxreaders(MDB_env *env, unsigned int readers)
+{
+	if (env->me_map || readers < 1)
+		return EINVAL;
+	env->me_maxreaders = readers;
+	return MDB_SUCCESS;
+}
+
+int ESECT
+mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers)
+{
+	if (!env || !readers)
+		return EINVAL;
+	*readers = env->me_maxreaders;
+	return MDB_SUCCESS;
+}
+
+/** Further setup required for opening an LMDB environment
+ */
+static int ESECT
+mdb_env_open2(MDB_env *env)
+{
+	unsigned int flags = env->me_flags;
+	int i, newenv = 0, rc;
+	MDB_meta meta;
+
+#ifdef _WIN32
+	/* See if we should use QueryLimited */
+	rc = GetVersion();
+	if ((rc & 0xff) > 5)
+		env->me_pidquery = MDB_PROCESS_QUERY_LIMITED_INFORMATION;
+	else
+		env->me_pidquery = PROCESS_QUERY_INFORMATION;
+#endif /* _WIN32 */
+
+	memset(&meta, 0, sizeof(meta));
+
+	if ((i = mdb_env_read_header(env, &meta)) != 0) {
+		if (i != ENOENT)
+			return i;
+		DPUTS("new mdbenv");
+		newenv = 1;
+		env->me_psize = env->me_os_psize;
+		if (env->me_psize > MAX_PAGESIZE)
+			env->me_psize = MAX_PAGESIZE;
+	} else {
+		env->me_psize = meta.mm_psize;
+	}
+
+	/* Was a mapsize configured? */
+	if (!env->me_mapsize) {
+		/* If this is a new environment, take the default,
+		 * else use the size recorded in the existing env.
+		 */
+		env->me_mapsize = newenv ? DEFAULT_MAPSIZE : meta.mm_mapsize;
+	} else if (env->me_mapsize < meta.mm_mapsize) {
+		/* If the configured size is smaller, make sure it's
+		 * still big enough. Silently round up to minimum if not.
+		 */
+		size_t minsize = (meta.mm_last_pg + 1) * meta.mm_psize;
+		if (env->me_mapsize < minsize)
+			env->me_mapsize = minsize;
+	}
+
+	rc = mdb_env_map(env, (flags & MDB_FIXEDMAP) ? meta.mm_address : NULL);
+	if (rc)
+		return rc;
+
+	if (newenv) {
+		if (flags & MDB_FIXEDMAP)
+			meta.mm_address = env->me_map;
+		i = mdb_env_init_meta(env, &meta);
+		if (i != MDB_SUCCESS) {
+			return i;
+		}
+	}
+
+	env->me_maxfree_1pg = (env->me_psize - PAGEHDRSZ) / sizeof(pgno_t) - 1;
+	env->me_nodemax = (((env->me_psize - PAGEHDRSZ) / MDB_MINKEYS) & -2)
+		- sizeof(indx_t);
+#if !(MDB_MAXKEYSIZE)
+	env->me_maxkey = env->me_nodemax - (NODESIZE + sizeof(MDB_db));
+#endif
+	env->me_maxpg = env->me_mapsize / env->me_psize;
+
+#if MDB_DEBUG
+	{
+		int toggle = mdb_env_pick_meta(env);
+		MDB_db *db = &env->me_metas[toggle]->mm_dbs[MAIN_DBI];
+
+		DPRINTF(("opened database version %u, pagesize %u",
+			env->me_metas[0]->mm_version, env->me_psize));
+		DPRINTF(("using meta page %d",    toggle));
+		DPRINTF(("depth: %u",             db->md_depth));
+		DPRINTF(("entries: %"Z"u",        db->md_entries));
+		DPRINTF(("branch pages: %"Z"u",   db->md_branch_pages));
+		DPRINTF(("leaf pages: %"Z"u",     db->md_leaf_pages));
+		DPRINTF(("overflow pages: %"Z"u", db->md_overflow_pages));
+		DPRINTF(("root: %"Z"u",           db->md_root));
+	}
+#endif
+
+	return MDB_SUCCESS;
+}
+
+
+/** Release a reader thread's slot in the reader lock table.
+ *	This function is called automatically when a thread exits.
+ * @param[in] ptr This points to the slot in the reader lock table.
+ */
+static void
+mdb_env_reader_dest(void *ptr)
+{
+	MDB_reader *reader = ptr;
+
+	reader->mr_pid = 0;
+}
+
+#ifdef _WIN32
+/** Junk for arranging thread-specific callbacks on Windows. This is
+ *	necessarily platform and compiler-specific. Windows supports up
+ *	to 1088 keys. Let's assume nobody opens more than 64 environments
+ *	in a single process, for now. They can override this if needed.
+ */
+#ifndef MAX_TLS_KEYS
+#define MAX_TLS_KEYS	64
+#endif
+static pthread_key_t mdb_tls_keys[MAX_TLS_KEYS];
+static int mdb_tls_nkeys;
+
+static void NTAPI mdb_tls_callback(PVOID module, DWORD reason, PVOID ptr)
+{
+	int i;
+	switch(reason) {
+	case DLL_PROCESS_ATTACH: break;
+	case DLL_THREAD_ATTACH: break;
+	case DLL_THREAD_DETACH:
+		for (i=0; i<mdb_tls_nkeys; i++) {
+			MDB_reader *r = pthread_getspecific(mdb_tls_keys[i]);
+			if (r) {
+				mdb_env_reader_dest(r);
+			}
+		}
+		break;
+	case DLL_PROCESS_DETACH: break;
+	}
+}
+#ifdef __GNUC__
+#ifdef _WIN64
+const PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
+#else
+PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
+#endif
+#else
+#ifdef _WIN64
+/* Force some symbol references.
+ *	_tls_used forces the linker to create the TLS directory if not already done
+ *	mdb_tls_cbp prevents whole-program-optimizer from dropping the symbol.
+ */
+#pragma comment(linker, "/INCLUDE:_tls_used")
+#pragma comment(linker, "/INCLUDE:mdb_tls_cbp")
+#pragma const_seg(".CRT$XLB")
+extern const PIMAGE_TLS_CALLBACK mdb_tls_cbp;
+const PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
+#pragma const_seg()
+#else	/* WIN32 */
+#pragma comment(linker, "/INCLUDE:__tls_used")
+#pragma comment(linker, "/INCLUDE:_mdb_tls_cbp")
+#pragma data_seg(".CRT$XLB")
+PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
+#pragma data_seg()
+#endif	/* WIN 32/64 */
+#endif	/* !__GNUC__ */
+#endif
+
+/** Downgrade the exclusive lock on the region back to shared */
+static int ESECT
+mdb_env_share_locks(MDB_env *env, int *excl)
+{
+	int rc = 0, toggle = mdb_env_pick_meta(env);
+
+	env->me_txns->mti_txnid = env->me_metas[toggle]->mm_txnid;
+
+#ifdef _WIN32
+	{
+		OVERLAPPED ov;
+		/* First acquire a shared lock. The Unlock will
+		 * then release the existing exclusive lock.
+		 */
+		memset(&ov, 0, sizeof(ov));
+		if (!LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
+			rc = ErrCode();
+		} else {
+			UnlockFile(env->me_lfd, 0, 0, 1, 0);
+			*excl = 0;
+		}
+	}
+#else
+	{
+		struct flock lock_info;
+		/* The shared lock replaces the existing lock */
+		memset((void *)&lock_info, 0, sizeof(lock_info));
+		lock_info.l_type = F_RDLCK;
+		lock_info.l_whence = SEEK_SET;
+		lock_info.l_start = 0;
+		lock_info.l_len = 1;
+		while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
+				(rc = ErrCode()) == EINTR) ;
+		*excl = rc ? -1 : 0;	/* error may mean we lost the lock */
+	}
+#endif
+
+	return rc;
+}
+
+/** Try to get exlusive lock, otherwise shared.
+ *	Maintain *excl = -1: no/unknown lock, 0: shared, 1: exclusive.
+ */
+static int ESECT
+mdb_env_excl_lock(MDB_env *env, int *excl)
+{
+	int rc = 0;
+#ifdef _WIN32
+	if (LockFile(env->me_lfd, 0, 0, 1, 0)) {
+		*excl = 1;
+	} else {
+		OVERLAPPED ov;
+		memset(&ov, 0, sizeof(ov));
+		if (LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
+			*excl = 0;
+		} else {
+			rc = ErrCode();
+		}
+	}
+#else
+	struct flock lock_info;
+	memset((void *)&lock_info, 0, sizeof(lock_info));
+	lock_info.l_type = F_WRLCK;
+	lock_info.l_whence = SEEK_SET;
+	lock_info.l_start = 0;
+	lock_info.l_len = 1;
+	while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
+			(rc = ErrCode()) == EINTR) ;
+	if (!rc) {
+		*excl = 1;
+	} else
+# ifdef MDB_USE_POSIX_SEM
+	if (*excl < 0) /* always true when !MDB_USE_POSIX_SEM */
+# endif
+	{
+		lock_info.l_type = F_RDLCK;
+		while ((rc = fcntl(env->me_lfd, F_SETLKW, &lock_info)) &&
+				(rc = ErrCode()) == EINTR) ;
+		if (rc == 0)
+			*excl = 0;
+	}
+#endif
+	return rc;
+}
+
+#ifdef MDB_USE_HASH
+/*
+ * hash_64 - 64 bit Fowler/Noll/Vo-0 FNV-1a hash code
+ *
+ * @(#) $Revision: 5.1 $
+ * @(#) $Id: hash_64a.c,v 5.1 2009/06/30 09:01:38 chongo Exp $
+ * @(#) $Source: /usr/local/src/cmd/fnv/RCS/hash_64a.c,v $
+ *
+ *	  http://www.isthe.com/chongo/tech/comp/fnv/index.html
+ *
+ ***
+ *
+ * Please do not copyright this code.  This code is in the public domain.
+ *
+ * LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
+ * EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
+ * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ *
+ * By:
+ *	chongo <Landon Curt Noll> /\oo/\
+ *	  http://www.isthe.com/chongo/
+ *
+ * Share and Enjoy!	:-)
+ */
+
+typedef unsigned long long	mdb_hash_t;
+#define MDB_HASH_INIT ((mdb_hash_t)0xcbf29ce484222325ULL)
+
+/** perform a 64 bit Fowler/Noll/Vo FNV-1a hash on a buffer
+ * @param[in] val	value to hash
+ * @param[in] hval	initial value for hash
+ * @return 64 bit hash
+ *
+ * NOTE: To use the recommended 64 bit FNV-1a hash, use MDB_HASH_INIT as the
+ * 	 hval arg on the first call.
+ */
+static mdb_hash_t
+mdb_hash_val(MDB_val *val, mdb_hash_t hval)
+{
+	unsigned char *s = (unsigned char *)val->mv_data;	/* unsigned string */
+	unsigned char *end = s + val->mv_size;
+	/*
+	 * FNV-1a hash each octet of the string
+	 */
+	while (s < end) {
+		/* xor the bottom with the current octet */
+		hval ^= (mdb_hash_t)*s++;
+
+		/* multiply by the 64 bit FNV magic prime mod 2^64 */
+		hval += (hval << 1) + (hval << 4) + (hval << 5) +
+			(hval << 7) + (hval << 8) + (hval << 40);
+	}
+	/* return our new hash value */
+	return hval;
+}
+
+/** Hash the string and output the encoded hash.
+ * This uses modified RFC1924 Ascii85 encoding to accommodate systems with
+ * very short name limits. We don't care about the encoding being reversible,
+ * we just want to preserve as many bits of the input as possible in a
+ * small printable string.
+ * @param[in] str string to hash
+ * @param[out] encbuf an array of 11 chars to hold the hash
+ */
+static const char mdb_a85[]= "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
+
+static void
+mdb_pack85(unsigned long l, char *out)
+{
+	int i;
+
+	for (i=0; i<5; i++) {
+		*out++ = mdb_a85[l % 85];
+		l /= 85;
+	}
+}
+
+static void
+mdb_hash_enc(MDB_val *val, char *encbuf)
+{
+	mdb_hash_t h = mdb_hash_val(val, MDB_HASH_INIT);
+
+	mdb_pack85(h, encbuf);
+	mdb_pack85(h>>32, encbuf+5);
+	encbuf[10] = '\0';
+}
+#endif
+
+/** Open and/or initialize the lock region for the environment.
+ * @param[in] env The LMDB environment.
+ * @param[in] lpath The pathname of the file used for the lock region.
+ * @param[in] mode The Unix permissions for the file, if we create it.
+ * @param[out] excl Resulting file lock type: -1 none, 0 shared, 1 exclusive
+ * @param[in,out] excl In -1, out lock type: -1 none, 0 shared, 1 exclusive
+ * @return 0 on success, non-zero on failure.
+ */
+static int ESECT
+mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
+{
+#ifdef _WIN32
+#	define MDB_ERRCODE_ROFS	ERROR_WRITE_PROTECT
+#else
+#	define MDB_ERRCODE_ROFS	EROFS
+#ifdef O_CLOEXEC	/* Linux: Open file and set FD_CLOEXEC atomically */
+#	define MDB_CLOEXEC		O_CLOEXEC
+#else
+	int fdflags;
+#	define MDB_CLOEXEC		0
+#endif
+#endif
+	int rc;
+	off_t size, rsize;
+
+#ifdef _WIN32
+	env->me_lfd = CreateFile(lpath, GENERIC_READ|GENERIC_WRITE,
+		FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS,
+		FILE_ATTRIBUTE_NORMAL, NULL);
+#else
+	env->me_lfd = open(lpath, O_RDWR|O_CREAT|MDB_CLOEXEC, mode);
+#endif
+	if (env->me_lfd == INVALID_HANDLE_VALUE) {
+		rc = ErrCode();
+		if (rc == MDB_ERRCODE_ROFS && (env->me_flags & MDB_RDONLY)) {
+			return MDB_SUCCESS;
+		}
+		goto fail_errno;
+	}
+#if ! ((MDB_CLOEXEC) || defined(_WIN32))
+	/* Lose record locks when exec*() */
+	if ((fdflags = fcntl(env->me_lfd, F_GETFD) | FD_CLOEXEC) >= 0)
+			fcntl(env->me_lfd, F_SETFD, fdflags);
+#endif
+
+	if (!(env->me_flags & MDB_NOTLS)) {
+		rc = pthread_key_create(&env->me_txkey, mdb_env_reader_dest);
+		if (rc)
+			goto fail;
+		env->me_flags |= MDB_ENV_TXKEY;
+#ifdef _WIN32
+		/* Windows TLS callbacks need help finding their TLS info. */
+		if (mdb_tls_nkeys >= MAX_TLS_KEYS) {
+			rc = MDB_TLS_FULL;
+			goto fail;
+		}
+		mdb_tls_keys[mdb_tls_nkeys++] = env->me_txkey;
+#endif
+	}
+
+	/* Try to get exclusive lock. If we succeed, then
+	 * nobody is using the lock region and we should initialize it.
+	 */
+	if ((rc = mdb_env_excl_lock(env, excl))) goto fail;
+
+#ifdef _WIN32
+	size = GetFileSize(env->me_lfd, NULL);
+#else
+	size = lseek(env->me_lfd, 0, SEEK_END);
+	if (size == -1) goto fail_errno;
+#endif
+	rsize = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);
+	if (size < rsize && *excl > 0) {
+#ifdef _WIN32
+		if (SetFilePointer(env->me_lfd, rsize, NULL, FILE_BEGIN) != (DWORD)rsize
+			|| !SetEndOfFile(env->me_lfd))
+			goto fail_errno;
+#else
+		if (ftruncate(env->me_lfd, rsize) != 0) goto fail_errno;
+#endif
+	} else {
+		rsize = size;
+		size = rsize - sizeof(MDB_txninfo);
+		env->me_maxreaders = size/sizeof(MDB_reader) + 1;
+	}
+	{
+#ifdef _WIN32
+		HANDLE mh;
+		mh = CreateFileMapping(env->me_lfd, NULL, PAGE_READWRITE,
+			0, 0, NULL);
+		if (!mh) goto fail_errno;
+		env->me_txns = MapViewOfFileEx(mh, FILE_MAP_WRITE, 0, 0, rsize, NULL);
+		CloseHandle(mh);
+		if (!env->me_txns) goto fail_errno;
+#else
+		void *m = mmap(NULL, rsize, PROT_READ|PROT_WRITE, MAP_SHARED,
+			env->me_lfd, 0);
+		if (m == MAP_FAILED) goto fail_errno;
+		env->me_txns = m;
+#endif
+	}
+	if (*excl > 0) {
+#ifdef _WIN32
+		BY_HANDLE_FILE_INFORMATION stbuf;
+		struct {
+			DWORD volume;
+			DWORD nhigh;
+			DWORD nlow;
+		} idbuf;
+		MDB_val val;
+		char encbuf[11];
+
+		if (!mdb_sec_inited) {
+			InitializeSecurityDescriptor(&mdb_null_sd,
+				SECURITY_DESCRIPTOR_REVISION);
+			SetSecurityDescriptorDacl(&mdb_null_sd, TRUE, 0, FALSE);
+			mdb_all_sa.nLength = sizeof(SECURITY_ATTRIBUTES);
+			mdb_all_sa.bInheritHandle = FALSE;
+			mdb_all_sa.lpSecurityDescriptor = &mdb_null_sd;
+			mdb_sec_inited = 1;
+		}
+		if (!GetFileInformationByHandle(env->me_lfd, &stbuf)) goto fail_errno;
+		idbuf.volume = stbuf.dwVolumeSerialNumber;
+		idbuf.nhigh  = stbuf.nFileIndexHigh;
+		idbuf.nlow   = stbuf.nFileIndexLow;
+		val.mv_data = &idbuf;
+		val.mv_size = sizeof(idbuf);
+		mdb_hash_enc(&val, encbuf);
+		sprintf(env->me_txns->mti_rmname, "Global\\MDBr%s", encbuf);
+		sprintf(env->me_txns->mti_wmname, "Global\\MDBw%s", encbuf);
+		env->me_rmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_rmname);
+		if (!env->me_rmutex) goto fail_errno;
+		env->me_wmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_wmname);
+		if (!env->me_wmutex) goto fail_errno;
+#elif defined(MDB_USE_POSIX_SEM)
+		struct stat stbuf;
+		struct {
+			dev_t dev;
+			ino_t ino;
+		} idbuf;
+		MDB_val val;
+		char encbuf[11];
+
+#if defined(__NetBSD__)
+#define	MDB_SHORT_SEMNAMES	1	/* limited to 14 chars */
+#endif
+		if (fstat(env->me_lfd, &stbuf)) goto fail_errno;
+		idbuf.dev = stbuf.st_dev;
+		idbuf.ino = stbuf.st_ino;
+		val.mv_data = &idbuf;
+		val.mv_size = sizeof(idbuf);
+		mdb_hash_enc(&val, encbuf);
+#ifdef MDB_SHORT_SEMNAMES
+		encbuf[9] = '\0';	/* drop name from 15 chars to 14 chars */
+#endif
+		sprintf(env->me_txns->mti_rmname, "/MDBr%s", encbuf);
+		sprintf(env->me_txns->mti_wmname, "/MDBw%s", encbuf);
+		/* Clean up after a previous run, if needed:  Try to
+		 * remove both semaphores before doing anything else.
+		 */
+		sem_unlink(env->me_txns->mti_rmname);
+		sem_unlink(env->me_txns->mti_wmname);
+		env->me_rmutex = sem_open(env->me_txns->mti_rmname,
+			O_CREAT|O_EXCL, mode, 1);
+		if (env->me_rmutex == SEM_FAILED) goto fail_errno;
+		env->me_wmutex = sem_open(env->me_txns->mti_wmname,
+			O_CREAT|O_EXCL, mode, 1);
+		if (env->me_wmutex == SEM_FAILED) goto fail_errno;
+#else	/* MDB_USE_POSIX_SEM */
+		pthread_mutexattr_t mattr;
+
+		if ((rc = pthread_mutexattr_init(&mattr))
+			|| (rc = pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED))
+			|| (rc = pthread_mutex_init(&env->me_txns->mti_mutex, &mattr))
+			|| (rc = pthread_mutex_init(&env->me_txns->mti_wmutex, &mattr)))
+			goto fail;
+		pthread_mutexattr_destroy(&mattr);
+#endif	/* _WIN32 || MDB_USE_POSIX_SEM */
+
+		env->me_txns->mti_magic = MDB_MAGIC;
+		env->me_txns->mti_format = MDB_LOCK_FORMAT;
+		env->me_txns->mti_txnid = 0;
+		env->me_txns->mti_numreaders = 0;
+
+	} else {
+		if (env->me_txns->mti_magic != MDB_MAGIC) {
+			DPUTS("lock region has invalid magic");
+			rc = MDB_INVALID;
+			goto fail;
+		}
+		if (env->me_txns->mti_format != MDB_LOCK_FORMAT) {
+			DPRINTF(("lock region has format+version 0x%x, expected 0x%x",
+				env->me_txns->mti_format, MDB_LOCK_FORMAT));
+			rc = MDB_VERSION_MISMATCH;
+			goto fail;
+		}
+		rc = ErrCode();
+		if (rc && rc != EACCES && rc != EAGAIN) {
+			goto fail;
+		}
+#ifdef _WIN32
+		env->me_rmutex = OpenMutex(SYNCHRONIZE, FALSE, env->me_txns->mti_rmname);
+		if (!env->me_rmutex) goto fail_errno;
+		env->me_wmutex = OpenMutex(SYNCHRONIZE, FALSE, env->me_txns->mti_wmname);
+		if (!env->me_wmutex) goto fail_errno;
+#elif defined(MDB_USE_POSIX_SEM)
+		env->me_rmutex = sem_open(env->me_txns->mti_rmname, 0);
+		if (env->me_rmutex == SEM_FAILED) goto fail_errno;
+		env->me_wmutex = sem_open(env->me_txns->mti_wmname, 0);
+		if (env->me_wmutex == SEM_FAILED) goto fail_errno;
+#endif
+	}
+	return MDB_SUCCESS;
+
+fail_errno:
+	rc = ErrCode();
+fail:
+	return rc;
+}
+
+	/** The name of the lock file in the DB environment */
+#define LOCKNAME	"/lock.mdb"
+	/** The name of the data file in the DB environment */
+#define DATANAME	"/data.mdb"
+	/** The suffix of the lock file when no subdir is used */
+#define LOCKSUFF	"-lock"
+	/** Only a subset of the @ref mdb_env flags can be changed
+	 *	at runtime. Changing other flags requires closing the
+	 *	environment and re-opening it with the new flags.
+	 */
+#define	CHANGEABLE	(MDB_NOSYNC|MDB_NOMETASYNC|MDB_MAPASYNC|MDB_NOMEMINIT)
+#define	CHANGELESS	(MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY|MDB_WRITEMAP| \
+	MDB_NOTLS|MDB_NOLOCK|MDB_NORDAHEAD)
+
+#if VALID_FLAGS & PERSISTENT_FLAGS & (CHANGEABLE|CHANGELESS)
+# error "Persistent DB flags & env flags overlap, but both go in mm_flags"
+#endif
+
+int ESECT
+mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode)
+{
+	int		oflags, rc, len, excl = -1;
+	char *lpath, *dpath;
+
+	if (env->me_fd!=INVALID_HANDLE_VALUE || (flags & ~(CHANGEABLE|CHANGELESS)))
+		return EINVAL;
+
+#ifdef VL32
+	if (flags & MDB_WRITEMAP) {
+		/* silently ignore WRITEMAP in 32 bit mode */
+		flags ^= MDB_WRITEMAP;
+	}
+	if (flags & MDB_FIXEDMAP) {
+		/* cannot support FIXEDMAP */
+		return EINVAL;
+	}
+#endif
+
+	len = strlen(path);
+	if (flags & MDB_NOSUBDIR) {
+		rc = len + sizeof(LOCKSUFF) + len + 1;
+	} else {
+		rc = len + sizeof(LOCKNAME) + len + sizeof(DATANAME);
+	}
+	lpath = malloc(rc);
+	if (!lpath)
+		return ENOMEM;
+	if (flags & MDB_NOSUBDIR) {
+		dpath = lpath + len + sizeof(LOCKSUFF);
+		sprintf(lpath, "%s" LOCKSUFF, path);
+		strcpy(dpath, path);
+	} else {
+		dpath = lpath + len + sizeof(LOCKNAME);
+		sprintf(lpath, "%s" LOCKNAME, path);
+		sprintf(dpath, "%s" DATANAME, path);
+	}
+
+	rc = MDB_SUCCESS;
+	flags |= env->me_flags;
+	if (flags & MDB_RDONLY) {
+		/* silently ignore WRITEMAP when we're only getting read access */
+		flags &= ~MDB_WRITEMAP;
+	} else {
+		if (!((env->me_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)) &&
+			  (env->me_dirty_list = calloc(MDB_IDL_UM_SIZE, sizeof(MDB_ID2)))))
+			rc = ENOMEM;
+	}
+	env->me_flags = flags |= MDB_ENV_ACTIVE;
+	if (rc)
+		goto leave;
+
+	env->me_path = strdup(path);
+	env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDB_dbx));
+	env->me_dbflags = calloc(env->me_maxdbs, sizeof(uint16_t));
+	env->me_dbiseqs = calloc(env->me_maxdbs, sizeof(unsigned int));
+	if (!(env->me_dbxs && env->me_path && env->me_dbflags && env->me_dbiseqs)) {
+		rc = ENOMEM;
+		goto leave;
+	}
+
+	/* For RDONLY, get lockfile after we know datafile exists */
+	if (!(flags & (MDB_RDONLY|MDB_NOLOCK))) {
+		rc = mdb_env_setup_locks(env, lpath, mode, &excl);
+		if (rc)
+			goto leave;
+	}
+
+#ifdef _WIN32
+	if (F_ISSET(flags, MDB_RDONLY)) {
+		oflags = GENERIC_READ;
+		len = OPEN_EXISTING;
+	} else {
+		oflags = GENERIC_READ|GENERIC_WRITE;
+		len = OPEN_ALWAYS;
+	}
+	mode = FILE_ATTRIBUTE_NORMAL;
+	env->me_fd = CreateFile(dpath, oflags, FILE_SHARE_READ|FILE_SHARE_WRITE,
+		NULL, len, mode, NULL);
+#else
+	if (F_ISSET(flags, MDB_RDONLY))
+		oflags = O_RDONLY;
+	else
+		oflags = O_RDWR | O_CREAT;
+
+	env->me_fd = open(dpath, oflags, mode);
+#endif
+	if (env->me_fd == INVALID_HANDLE_VALUE) {
+		rc = ErrCode();
+		goto leave;
+	}
+
+	if ((flags & (MDB_RDONLY|MDB_NOLOCK)) == MDB_RDONLY) {
+		rc = mdb_env_setup_locks(env, lpath, mode, &excl);
+		if (rc)
+			goto leave;
+	}
+
+	if ((rc = mdb_env_open2(env)) == MDB_SUCCESS) {
+		if (flags & (MDB_RDONLY|MDB_WRITEMAP)) {
+			env->me_mfd = env->me_fd;
+		} else {
+			/* Synchronous fd for meta writes. Needed even with
+			 * MDB_NOSYNC/MDB_NOMETASYNC, in case these get reset.
+			 */
+#ifdef _WIN32
+			len = OPEN_EXISTING;
+			env->me_mfd = CreateFile(dpath, oflags,
+				FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, len,
+				mode | FILE_FLAG_WRITE_THROUGH, NULL);
+#else
+			oflags &= ~O_CREAT;
+			env->me_mfd = open(dpath, oflags | MDB_DSYNC, mode);
+#endif
+			if (env->me_mfd == INVALID_HANDLE_VALUE) {
+				rc = ErrCode();
+				goto leave;
+			}
+		}
+		DPRINTF(("opened dbenv %p", (void *) env));
+		if (excl > 0) {
+			rc = mdb_env_share_locks(env, &excl);
+			if (rc)
+				goto leave;
+		}
+		if (!((flags & MDB_RDONLY) ||
+			  (env->me_pbuf = calloc(1, env->me_psize))))
+			rc = ENOMEM;
+		if (!(flags & MDB_RDONLY)) {
+			MDB_txn *txn;
+			int tsize = sizeof(MDB_txn), size = tsize + env->me_maxdbs *
+				(sizeof(MDB_db)+sizeof(MDB_cursor)+sizeof(unsigned int)+1);
+			txn = calloc(1, size);
+			if (txn) {
+				txn->mt_dbs = (MDB_db *)((char *)txn + tsize);
+				txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
+				txn->mt_dbiseqs = (unsigned int *)(txn->mt_cursors + env->me_maxdbs);
+				txn->mt_dbflags = (unsigned char *)(txn->mt_dbiseqs + env->me_maxdbs);
+				txn->mt_env = env;
+#ifdef VL32
+				txn->mt_rpages = calloc(MDB_IDL_UM_SIZE, sizeof(MDB_ID2));
+				if (!txn->mt_rpages) {
+					free(txn);
+					rc = ENOMEM;
+				}
+#endif
+				env->me_txn0 = txn;
+			} else {
+				rc = ENOMEM;
+			}
+		}
+	}
+
+leave:
+	if (rc) {
+		mdb_env_close0(env, excl);
+	}
+	free(lpath);
+	return rc;
+}
+
+/** Destroy resources from mdb_env_open(), clear our readers & DBIs */
+static void ESECT
+mdb_env_close0(MDB_env *env, int excl)
+{
+	int i;
+
+	if (!(env->me_flags & MDB_ENV_ACTIVE))
+		return;
+
+	/* Doing this here since me_dbxs may not exist during mdb_env_close */
+	for (i = env->me_maxdbs; --i > MAIN_DBI; )
+		free(env->me_dbxs[i].md_name.mv_data);
+
+	free(env->me_pbuf);
+	free(env->me_dbiseqs);
+	free(env->me_dbflags);
+	free(env->me_dbxs);
+	free(env->me_path);
+	free(env->me_dirty_list);
+	free(env->me_txn0);
+	mdb_midl_free(env->me_free_pgs);
+
+	if (env->me_flags & MDB_ENV_TXKEY) {
+		pthread_key_delete(env->me_txkey);
+#ifdef _WIN32
+		/* Delete our key from the global list */
+		for (i=0; i<mdb_tls_nkeys; i++)
+			if (mdb_tls_keys[i] == env->me_txkey) {
+				mdb_tls_keys[i] = mdb_tls_keys[mdb_tls_nkeys-1];
+				mdb_tls_nkeys--;
+				break;
+			}
+#endif
+	}
+
+	if (env->me_map) {
+#ifdef VL32
+		munmap(env->me_map, 2*env->me_psize);
+#else
+		munmap(env->me_map, env->me_mapsize);
+#endif
+	}
+	if (env->me_mfd != env->me_fd && env->me_mfd != INVALID_HANDLE_VALUE)
+		(void) close(env->me_mfd);
+	if (env->me_fd != INVALID_HANDLE_VALUE)
+		(void) close(env->me_fd);
+	if (env->me_txns) {
+		MDB_PID_T pid = env->me_pid;
+		/* Clearing readers is done in this function because
+		 * me_txkey with its destructor must be disabled first.
+		 */
+		for (i = env->me_numreaders; --i >= 0; )
+			if (env->me_txns->mti_readers[i].mr_pid == pid)
+				env->me_txns->mti_readers[i].mr_pid = 0;
+#ifdef _WIN32
+		if (env->me_rmutex) {
+			CloseHandle(env->me_rmutex);
+			if (env->me_wmutex) CloseHandle(env->me_wmutex);
+		}
+		/* Windows automatically destroys the mutexes when
+		 * the last handle closes.
+		 */
+#elif defined(MDB_USE_POSIX_SEM)
+		if (env->me_rmutex != SEM_FAILED) {
+			sem_close(env->me_rmutex);
+			if (env->me_wmutex != SEM_FAILED)
+				sem_close(env->me_wmutex);
+			/* If we have the filelock:  If we are the
+			 * only remaining user, clean up semaphores.
+			 */
+			if (excl == 0)
+				mdb_env_excl_lock(env, &excl);
+			if (excl > 0) {
+				sem_unlink(env->me_txns->mti_rmname);
+				sem_unlink(env->me_txns->mti_wmname);
+			}
+		}
+#endif
+		munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
+	}
+	if (env->me_lfd != INVALID_HANDLE_VALUE) {
+#ifdef _WIN32
+		if (excl >= 0) {
+			/* Unlock the lockfile.  Windows would have unlocked it
+			 * after closing anyway, but not necessarily at once.
+			 */
+			UnlockFile(env->me_lfd, 0, 0, 1, 0);
+		}
+#endif
+		(void) close(env->me_lfd);
+	}
+
+	env->me_flags &= ~(MDB_ENV_ACTIVE|MDB_ENV_TXKEY);
+}
+
+
+void ESECT
+mdb_env_close(MDB_env *env)
+{
+	MDB_page *dp;
+
+	if (env == NULL)
+		return;
+
+	VGMEMP_DESTROY(env);
+	while ((dp = env->me_dpages) != NULL) {
+		VGMEMP_DEFINED(&dp->mp_next, sizeof(dp->mp_next));
+		env->me_dpages = dp->mp_next;
+		free(dp);
+	}
+
+	mdb_env_close0(env, 0);
+	free(env);
+}
+
+/** Compare two items pointing at aligned size_t's */
+static int
+mdb_cmp_long(const MDB_val *a, const MDB_val *b)
+{
+	return (*(size_t *)a->mv_data < *(size_t *)b->mv_data) ? -1 :
+		*(size_t *)a->mv_data > *(size_t *)b->mv_data;
+}
+
+/** Compare two items pointing at aligned unsigned int's */
+static int
+mdb_cmp_int(const MDB_val *a, const MDB_val *b)
+{
+	return (*(unsigned int *)a->mv_data < *(unsigned int *)b->mv_data) ? -1 :
+		*(unsigned int *)a->mv_data > *(unsigned int *)b->mv_data;
+}
+
+/** Compare two items pointing at unsigned ints of unknown alignment.
+ *	Nodes and keys are guaranteed to be 2-byte aligned.
+ */
+static int
+mdb_cmp_cint(const MDB_val *a, const MDB_val *b)
+{
+#if BYTE_ORDER == LITTLE_ENDIAN
+	unsigned short *u, *c;
+	int x;
+
+	u = (unsigned short *) ((char *) a->mv_data + a->mv_size);
+	c = (unsigned short *) ((char *) b->mv_data + a->mv_size);
+	do {
+		x = *--u - *--c;
+	} while(!x && u > (unsigned short *)a->mv_data);
+	return x;
+#else
+	unsigned short *u, *c, *end;
+	int x;
+
+	end = (unsigned short *) ((char *) a->mv_data + a->mv_size);
+	u = (unsigned short *)a->mv_data;
+	c = (unsigned short *)b->mv_data;
+	do {
+		x = *u++ - *c++;
+	} while(!x && u < end);
+	return x;
+#endif
+}
+
+/** Compare two items pointing at size_t's of unknown alignment. */
+#ifdef MISALIGNED_OK
+# define mdb_cmp_clong mdb_cmp_long
+#else
+# define mdb_cmp_clong mdb_cmp_cint
+#endif
+
+/** Compare two items lexically */
+static int
+mdb_cmp_memn(const MDB_val *a, const MDB_val *b)
+{
+	int diff;
+	ssize_t len_diff;
+	unsigned int len;
+
+	len = a->mv_size;
+	len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
+	if (len_diff > 0) {
+		len = b->mv_size;
+		len_diff = 1;
+	}
+
+	diff = memcmp(a->mv_data, b->mv_data, len);
+	return diff ? diff : len_diff<0 ? -1 : len_diff;
+}
+
+/** Compare two items in reverse byte order */
+static int
+mdb_cmp_memnr(const MDB_val *a, const MDB_val *b)
+{
+	const unsigned char	*p1, *p2, *p1_lim;
+	ssize_t len_diff;
+	int diff;
+
+	p1_lim = (const unsigned char *)a->mv_data;
+	p1 = (const unsigned char *)a->mv_data + a->mv_size;
+	p2 = (const unsigned char *)b->mv_data + b->mv_size;
+
+	len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
+	if (len_diff > 0) {
+		p1_lim += len_diff;
+		len_diff = 1;
+	}
+
+	while (p1 > p1_lim) {
+		diff = *--p1 - *--p2;
+		if (diff)
+			return diff;
+	}
+	return len_diff<0 ? -1 : len_diff;
+}
+
+/** Search for key within a page, using binary search.
+ * Returns the smallest entry larger or equal to the key.
+ * If exactp is non-null, stores whether the found entry was an exact match
+ * in *exactp (1 or 0).
+ * Updates the cursor index with the index of the found entry.
+ * If no entry larger or equal to the key is found, returns NULL.
+ */
+static MDB_node *
+mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp)
+{
+	unsigned int	 i = 0, nkeys;
+	int		 low, high;
+	int		 rc = 0;
+	MDB_page *mp = mc->mc_pg[mc->mc_top];
+	MDB_node	*node = NULL;
+	MDB_val	 nodekey;
+	MDB_cmp_func *cmp;
+	DKBUF;
+
+	nkeys = NUMKEYS(mp);
+
+	DPRINTF(("searching %u keys in %s %spage %"Z"u",
+	    nkeys, IS_LEAF(mp) ? "leaf" : "branch", IS_SUBP(mp) ? "sub-" : "",
+	    mdb_dbg_pgno(mp)));
+
+	low = IS_LEAF(mp) ? 0 : 1;
+	high = nkeys - 1;
+	cmp = mc->mc_dbx->md_cmp;
+
+	/* Branch pages have no data, so if using integer keys,
+	 * alignment is guaranteed. Use faster mdb_cmp_int.
+	 */
+	if (cmp == mdb_cmp_cint && IS_BRANCH(mp)) {
+		if (NODEPTR(mp, 1)->mn_ksize == sizeof(size_t))
+			cmp = mdb_cmp_long;
+		else
+			cmp = mdb_cmp_int;
+	}
+
+	if (IS_LEAF2(mp)) {
+		nodekey.mv_size = mc->mc_db->md_pad;
+		node = NODEPTR(mp, 0);	/* fake */
+		while (low <= high) {
+			i = (low + high) >> 1;
+			nodekey.mv_data = LEAF2KEY(mp, i, nodekey.mv_size);
+			rc = cmp(key, &nodekey);
+			DPRINTF(("found leaf index %u [%s], rc = %i",
+			    i, DKEY(&nodekey), rc));
+			if (rc == 0)
+				break;
+			if (rc > 0)
+				low = i + 1;
+			else
+				high = i - 1;
+		}
+	} else {
+		while (low <= high) {
+			i = (low + high) >> 1;
+
+			node = NODEPTR(mp, i);
+			nodekey.mv_size = NODEKSZ(node);
+			nodekey.mv_data = NODEKEY(node);
+
+			rc = cmp(key, &nodekey);
+#if MDB_DEBUG
+			if (IS_LEAF(mp))
+				DPRINTF(("found leaf index %u [%s], rc = %i",
+				    i, DKEY(&nodekey), rc));
+			else
+				DPRINTF(("found branch index %u [%s -> %"Z"u], rc = %i",
+				    i, DKEY(&nodekey), NODEPGNO(node), rc));
+#endif
+			if (rc == 0)
+				break;
+			if (rc > 0)
+				low = i + 1;
+			else
+				high = i - 1;
+		}
+	}
+
+	if (rc > 0) {	/* Found entry is less than the key. */
+		i++;	/* Skip to get the smallest entry larger than key. */
+		if (!IS_LEAF2(mp))
+			node = NODEPTR(mp, i);
+	}
+	if (exactp)
+		*exactp = (rc == 0 && nkeys > 0);
+	/* store the key index */
+	mc->mc_ki[mc->mc_top] = i;
+	if (i >= nkeys)
+		/* There is no entry larger or equal to the key. */
+		return NULL;
+
+	/* nodeptr is fake for LEAF2 */
+	return node;
+}
+
+#if 0
+static void
+mdb_cursor_adjust(MDB_cursor *mc, func)
+{
+	MDB_cursor *m2;
+
+	for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
+		if (m2->mc_pg[m2->mc_top] == mc->mc_pg[mc->mc_top]) {
+			func(mc, m2);
+		}
+	}
+}
+#endif
+
+/** Pop a page off the top of the cursor's stack. */
+static void
+mdb_cursor_pop(MDB_cursor *mc)
+{
+	if (mc->mc_snum) {
+#if MDB_DEBUG
+		MDB_page	*top = mc->mc_pg[mc->mc_top];
+#endif
+		mc->mc_snum--;
+		if (mc->mc_snum)
+			mc->mc_top--;
+
+		DPRINTF(("popped page %"Z"u off db %d cursor %p", top->mp_pgno,
+			DDBI(mc), (void *) mc));
+	}
+}
+
+/** Push a page onto the top of the cursor's stack. */
+static int
+mdb_cursor_push(MDB_cursor *mc, MDB_page *mp)
+{
+	DPRINTF(("pushing page %"Z"u on db %d cursor %p", mp->mp_pgno,
+		DDBI(mc), (void *) mc));
+
+	if (mc->mc_snum >= CURSOR_STACK) {
+		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
+		return MDB_CURSOR_FULL;
+	}
+
+	mc->mc_top = mc->mc_snum++;
+	mc->mc_pg[mc->mc_top] = mp;
+	mc->mc_ki[mc->mc_top] = 0;
+
+	return MDB_SUCCESS;
+}
+
+/** Find the address of the page corresponding to a given page number.
+ * @param[in] txn the transaction for this access.
+ * @param[in] pgno the page number for the page to retrieve.
+ * @param[out] ret address of a pointer where the page's address will be stored.
+ * @param[out] lvl dirty_list inheritance level of found page. 1=current txn, 0=mapped page.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_page_get(MDB_txn *txn, pgno_t pgno, MDB_page **ret, int *lvl)
+{
+	MDB_env *env = txn->mt_env;
+	MDB_page *p = NULL;
+	int level;
+
+	if (!((txn->mt_flags & MDB_TXN_RDONLY) | (env->me_flags & MDB_WRITEMAP))) {
+		MDB_txn *tx2 = txn;
+		level = 1;
+		do {
+			MDB_ID2L dl = tx2->mt_u.dirty_list;
+			unsigned x;
+			/* Spilled pages were dirtied in this txn and flushed
+			 * because the dirty list got full. Bring this page
+			 * back in from the map (but don't unspill it here,
+			 * leave that unless page_touch happens again).
+			 */
+			if (tx2->mt_spill_pgs) {
+				MDB_ID pn = pgno << 1;
+				x = mdb_midl_search(tx2->mt_spill_pgs, pn);
+				if (x <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[x] == pn) {
+					p = (MDB_page *)(env->me_map + env->me_psize * pgno);
+					goto done;
+				}
+			}
+			if (dl[0].mid) {
+				unsigned x = mdb_mid2l_search(dl, pgno);
+				if (x <= dl[0].mid && dl[x].mid == pgno) {
+					p = dl[x].mptr;
+					goto done;
+				}
+			}
+			level++;
+		} while ((tx2 = tx2->mt_parent) != NULL);
+	}
+
+	if (pgno < txn->mt_next_pgno) {
+		level = 0;
+#ifdef VL32
+		{
+			unsigned x = mdb_mid2l_search(txn->mt_rpages, pgno);
+			if (x <= txn->mt_rpages[0].mid && txn->mt_rpages[x].mid == pgno) {
+				p = txn->mt_rpages[x].mptr;
+				goto done;
+			}
+			if (txn->mt_rpages[0].mid >= MDB_IDL_UM_MAX) {
+				/* unmap some other page */
+				mdb_tassert(txn, 0);
+			}
+			if (txn->mt_rpages[0].mid < MDB_IDL_UM_SIZE) {
+				MDB_ID2 id2;
+				size_t len = env->me_psize;
+				int np;
+#ifdef _WIN32
+				size_t off = pgno * env->me_psize;
+				DWORD lo, hi;
+				lo = off & 0xffffffff;
+				hi = off >> 16 >> 16;
+				p = MapViewOfFile(env->me_fmh, FILE_MAP_READ, hi, lo, len);
+				if (p == NULL)
+					return ErrCode();
+				if (IS_OVERFLOW(p)) {
+					np = p->mp_pages;
+					UnmapViewOfFile(p);
+					len *= np;
+					p = MapViewOfFile(env->me_fmh, FILE_MAP_READ, hi, lo, len);
+					if (p == NULL)
+						return ErrCode();
+				}
+#else
+				off_t off = pgno * env->me_psize;
+				p = mmap(NULL, len, PROT_READ, MAP_SHARED, env->me_fd, off);
+				if (p == MAP_FAILED)
+					return errno;
+				if (IS_OVERFLOW(p)) {
+					np = p->mp_pages;
+					munmap(p, len);
+					len *= np;
+					p = mmap(NULL, len, PROT_READ, MAP_SHARED, env->me_fd, off);
+					if (p == MAP_FAILED)
+						return errno;
+				}
+#endif
+				id2.mid = pgno;
+				id2.mptr = p;
+				mdb_mid2l_insert(txn->mt_rpages, &id2);
+				goto done;
+			}
+		}
+#else
+		p = (MDB_page *)(env->me_map + env->me_psize * pgno);
+#endif
+	} else {
+		DPRINTF(("page %"Z"u not found", pgno));
+		txn->mt_flags |= MDB_TXN_ERROR;
+		return MDB_PAGE_NOTFOUND;
+	}
+
+done:
+	*ret = p;
+	if (lvl)
+		*lvl = level;
+	return MDB_SUCCESS;
+}
+
+/** Finish #mdb_page_search() / #mdb_page_search_lowest().
+ *	The cursor is at the root page, set up the rest of it.
+ */
+static int
+mdb_page_search_root(MDB_cursor *mc, MDB_val *key, int flags)
+{
+	MDB_page	*mp = mc->mc_pg[mc->mc_top];
+	int rc;
+	DKBUF;
+
+	while (IS_BRANCH(mp)) {
+		MDB_node	*node;
+		indx_t		i;
+
+		DPRINTF(("branch page %"Z"u has %u keys", mp->mp_pgno, NUMKEYS(mp)));
+		mdb_cassert(mc, NUMKEYS(mp) > 1);
+		DPRINTF(("found index 0 to page %"Z"u", NODEPGNO(NODEPTR(mp, 0))));
+
+		if (flags & (MDB_PS_FIRST|MDB_PS_LAST)) {
+			i = 0;
+			if (flags & MDB_PS_LAST)
+				i = NUMKEYS(mp) - 1;
+		} else {
+			int	 exact;
+			node = mdb_node_search(mc, key, &exact);
+			if (node == NULL)
+				i = NUMKEYS(mp) - 1;
+			else {
+				i = mc->mc_ki[mc->mc_top];
+				if (!exact) {
+					mdb_cassert(mc, i > 0);
+					i--;
+				}
+			}
+			DPRINTF(("following index %u for key [%s]", i, DKEY(key)));
+		}
+
+		mdb_cassert(mc, i < NUMKEYS(mp));
+		node = NODEPTR(mp, i);
+
+		if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mp, NULL)) != 0)
+			return rc;
+
+		mc->mc_ki[mc->mc_top] = i;
+		if ((rc = mdb_cursor_push(mc, mp)))
+			return rc;
+
+		if (flags & MDB_PS_MODIFY) {
+			if ((rc = mdb_page_touch(mc)) != 0)
+				return rc;
+			mp = mc->mc_pg[mc->mc_top];
+		}
+	}
+
+	if (!IS_LEAF(mp)) {
+		DPRINTF(("internal error, index points to a %02X page!?",
+		    mp->mp_flags));
+		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
+		return MDB_CORRUPTED;
+	}
+
+	DPRINTF(("found leaf page %"Z"u for key [%s]", mp->mp_pgno,
+	    key ? DKEY(key) : "null"));
+	mc->mc_flags |= C_INITIALIZED;
+	mc->mc_flags &= ~C_EOF;
+
+	return MDB_SUCCESS;
+}
+
+/** Search for the lowest key under the current branch page.
+ * This just bypasses a NUMKEYS check in the current page
+ * before calling mdb_page_search_root(), because the callers
+ * are all in situations where the current page is known to
+ * be underfilled.
+ */
+static int
+mdb_page_search_lowest(MDB_cursor *mc)
+{
+	MDB_page	*mp = mc->mc_pg[mc->mc_top];
+	MDB_node	*node = NODEPTR(mp, 0);
+	int rc;
+
+	if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mp, NULL)) != 0)
+		return rc;
+
+	mc->mc_ki[mc->mc_top] = 0;
+	if ((rc = mdb_cursor_push(mc, mp)))
+		return rc;
+	return mdb_page_search_root(mc, NULL, MDB_PS_FIRST);
+}
+
+/** Search for the page a given key should be in.
+ * Push it and its parent pages on the cursor stack.
+ * @param[in,out] mc the cursor for this operation.
+ * @param[in] key the key to search for, or NULL for first/last page.
+ * @param[in] flags If MDB_PS_MODIFY is set, visited pages in the DB
+ *   are touched (updated with new page numbers).
+ *   If MDB_PS_FIRST or MDB_PS_LAST is set, find first or last leaf.
+ *   This is used by #mdb_cursor_first() and #mdb_cursor_last().
+ *   If MDB_PS_ROOTONLY set, just fetch root node, no further lookups.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_page_search(MDB_cursor *mc, MDB_val *key, int flags)
+{
+	int		 rc;
+	pgno_t		 root;
+
+	/* Make sure the txn is still viable, then find the root from
+	 * the txn's db table and set it as the root of the cursor's stack.
+	 */
+	if (F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_ERROR)) {
+		DPUTS("transaction has failed, must abort");
+		return MDB_BAD_TXN;
+	} else {
+		/* Make sure we're using an up-to-date root */
+		if (*mc->mc_dbflag & DB_STALE) {
+				MDB_cursor mc2;
+				if (TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))
+					return MDB_BAD_DBI;
+				mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
+				rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, 0);
+				if (rc)
+					return rc;
+				{
+					MDB_val data;
+					int exact = 0;
+					uint16_t flags;
+					MDB_node *leaf = mdb_node_search(&mc2,
+						&mc->mc_dbx->md_name, &exact);
+					if (!exact)
+						return MDB_NOTFOUND;
+					rc = mdb_node_read(mc->mc_txn, leaf, &data);
+					if (rc)
+						return rc;
+					memcpy(&flags, ((char *) data.mv_data + offsetof(MDB_db, md_flags)),
+						sizeof(uint16_t));
+					/* The txn may not know this DBI, or another process may
+					 * have dropped and recreated the DB with other flags.
+					 */
+					if ((mc->mc_db->md_flags & PERSISTENT_FLAGS) != flags)
+						return MDB_INCOMPATIBLE;
+					memcpy(mc->mc_db, data.mv_data, sizeof(MDB_db));
+				}
+				*mc->mc_dbflag &= ~DB_STALE;
+		}
+		root = mc->mc_db->md_root;
+
+		if (root == P_INVALID) {		/* Tree is empty. */
+			DPUTS("tree is empty");
+			return MDB_NOTFOUND;
+		}
+	}
+
+	mdb_cassert(mc, root > 1);
+	if (!mc->mc_pg[0] || mc->mc_pg[0]->mp_pgno != root)
+		if ((rc = mdb_page_get(mc->mc_txn, root, &mc->mc_pg[0], NULL)) != 0)
+			return rc;
+
+	mc->mc_snum = 1;
+	mc->mc_top = 0;
+
+	DPRINTF(("db %d root page %"Z"u has flags 0x%X",
+		DDBI(mc), root, mc->mc_pg[0]->mp_flags));
+
+	if (flags & MDB_PS_MODIFY) {
+		if ((rc = mdb_page_touch(mc)))
+			return rc;
+	}
+
+	if (flags & MDB_PS_ROOTONLY)
+		return MDB_SUCCESS;
+
+	return mdb_page_search_root(mc, key, flags);
+}
+
+static int
+mdb_ovpage_free(MDB_cursor *mc, MDB_page *mp)
+{
+	MDB_txn *txn = mc->mc_txn;
+	pgno_t pg = mp->mp_pgno;
+	unsigned x = 0, ovpages = mp->mp_pages;
+	MDB_env *env = txn->mt_env;
+	MDB_IDL sl = txn->mt_spill_pgs;
+	MDB_ID pn = pg << 1;
+	int rc;
+
+	DPRINTF(("free ov page %"Z"u (%d)", pg, ovpages));
+	/* If the page is dirty or on the spill list we just acquired it,
+	 * so we should give it back to our current free list, if any.
+	 * Otherwise put it onto the list of pages we freed in this txn.
+	 *
+	 * Won't create me_pghead: me_pglast must be inited along with it.
+	 * Unsupported in nested txns: They would need to hide the page
+	 * range in ancestor txns' dirty and spilled lists.
+	 */
+	if (env->me_pghead &&
+		!txn->mt_parent &&
+		((mp->mp_flags & P_DIRTY) ||
+		 (sl && (x = mdb_midl_search(sl, pn)) <= sl[0] && sl[x] == pn)))
+	{
+		unsigned i, j;
+		pgno_t *mop;
+		MDB_ID2 *dl, ix, iy;
+		rc = mdb_midl_need(&env->me_pghead, ovpages);
+		if (rc)
+			return rc;
+		if (!(mp->mp_flags & P_DIRTY)) {
+			/* This page is no longer spilled */
+			if (x == sl[0])
+				sl[0]--;
+			else
+				sl[x] |= 1;
+			goto release;
+		}
+		/* Remove from dirty list */
+		dl = txn->mt_u.dirty_list;
+		x = dl[0].mid--;
+		for (ix = dl[x]; ix.mptr != mp; ix = iy) {
+			if (x > 1) {
+				x--;
+				iy = dl[x];
+				dl[x] = ix;
+			} else {
+				mdb_cassert(mc, x > 1);
+				j = ++(dl[0].mid);
+				dl[j] = ix;		/* Unsorted. OK when MDB_TXN_ERROR. */
+				txn->mt_flags |= MDB_TXN_ERROR;
+				return MDB_CORRUPTED;
+			}
+		}
+		if (!(env->me_flags & MDB_WRITEMAP))
+			mdb_dpage_free(env, mp);
+release:
+		/* Insert in me_pghead */
+		mop = env->me_pghead;
+		j = mop[0] + ovpages;
+		for (i = mop[0]; i && mop[i] < pg; i--)
+			mop[j--] = mop[i];
+		while (j>i)
+			mop[j--] = pg++;
+		mop[0] += ovpages;
+	} else {
+		rc = mdb_midl_append_range(&txn->mt_free_pgs, pg, ovpages);
+		if (rc)
+			return rc;
+	}
+	mc->mc_db->md_overflow_pages -= ovpages;
+	return 0;
+}
+
+/** Return the data associated with a given node.
+ * @param[in] txn The transaction for this operation.
+ * @param[in] leaf The node being read.
+ * @param[out] data Updated to point to the node's data.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_node_read(MDB_txn *txn, MDB_node *leaf, MDB_val *data)
+{
+	MDB_page	*omp;		/* overflow page */
+	pgno_t		 pgno;
+	int rc;
+
+	if (!F_ISSET(leaf->mn_flags, F_BIGDATA)) {
+		data->mv_size = NODEDSZ(leaf);
+		data->mv_data = NODEDATA(leaf);
+		return MDB_SUCCESS;
+	}
+
+	/* Read overflow data.
+	 */
+	data->mv_size = NODEDSZ(leaf);
+	memcpy(&pgno, NODEDATA(leaf), sizeof(pgno));
+	if ((rc = mdb_page_get(txn, pgno, &omp, NULL)) != 0) {
+		DPRINTF(("read overflow page %"Z"u failed", pgno));
+		return rc;
+	}
+	data->mv_data = METADATA(omp);
+
+	return MDB_SUCCESS;
+}
+
+int
+mdb_get(MDB_txn *txn, MDB_dbi dbi,
+    MDB_val *key, MDB_val *data)
+{
+	MDB_cursor	mc;
+	MDB_xcursor	mx;
+	int exact = 0;
+	DKBUF;
+
+	DPRINTF(("===> get db %u key [%s]", dbi, DKEY(key)));
+
+	if (!key || !data || dbi == FREE_DBI || !TXN_DBI_EXIST(txn, dbi))
+		return EINVAL;
+
+	if (txn->mt_flags & MDB_TXN_ERROR)
+		return MDB_BAD_TXN;
+
+	mdb_cursor_init(&mc, txn, dbi, &mx);
+	return mdb_cursor_set(&mc, key, data, MDB_SET, &exact);
+}
+
+/** Find a sibling for a page.
+ * Replaces the page at the top of the cursor's stack with the
+ * specified sibling, if one exists.
+ * @param[in] mc The cursor for this operation.
+ * @param[in] move_right Non-zero if the right sibling is requested,
+ * otherwise the left sibling.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_cursor_sibling(MDB_cursor *mc, int move_right)
+{
+	int		 rc;
+	MDB_node	*indx;
+	MDB_page	*mp;
+#ifdef VL32
+	MDB_page	*op;
+#endif
+
+	if (mc->mc_snum < 2) {
+		return MDB_NOTFOUND;		/* root has no siblings */
+	}
+
+#ifdef VL32
+	op = mc->mc_pg[mc->mc_top];
+#endif
+	mdb_cursor_pop(mc);
+	DPRINTF(("parent page is page %"Z"u, index %u",
+		mc->mc_pg[mc->mc_top]->mp_pgno, mc->mc_ki[mc->mc_top]));
+
+	if (move_right ? (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mc->mc_pg[mc->mc_top]))
+		       : (mc->mc_ki[mc->mc_top] == 0)) {
+		DPRINTF(("no more keys left, moving to %s sibling",
+		    move_right ? "right" : "left"));
+		if ((rc = mdb_cursor_sibling(mc, move_right)) != MDB_SUCCESS) {
+			/* undo cursor_pop before returning */
+			mc->mc_top++;
+			mc->mc_snum++;
+			return rc;
+		}
+	} else {
+		if (move_right)
+			mc->mc_ki[mc->mc_top]++;
+		else
+			mc->mc_ki[mc->mc_top]--;
+		DPRINTF(("just moving to %s index key %u",
+		    move_right ? "right" : "left", mc->mc_ki[mc->mc_top]));
+	}
+	mdb_cassert(mc, IS_BRANCH(mc->mc_pg[mc->mc_top]));
+
+#ifdef VL32
+	{
+		MDB_ID2L rl = mc->mc_txn->mt_rpages;
+		unsigned x = mdb_mid2l_search(rl, op->mp_pgno);
+		if (x <= rl[0].mid && rl[x].mid == op->mp_pgno) {
+			munmap(op, mc->mc_txn->mt_env->me_psize);
+			while (x < rl[0].mid) {
+				rl[x] = rl[x+1];
+				x++;
+			}
+			rl[0].mid--;
+		}
+	}
+#endif
+
+	indx = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
+	if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(indx), &mp, NULL)) != 0) {
+		/* mc will be inconsistent if caller does mc_snum++ as above */
+		mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
+		return rc;
+	}
+
+	mdb_cursor_push(mc, mp);
+	if (!move_right)
+		mc->mc_ki[mc->mc_top] = NUMKEYS(mp)-1;
+
+	return MDB_SUCCESS;
+}
+
+/** Move the cursor to the next data item. */
+static int
+mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
+{
+	MDB_page	*mp;
+	MDB_node	*leaf;
+	int rc;
+
+	if (mc->mc_flags & C_EOF) {
+		return MDB_NOTFOUND;
+	}
+
+	mdb_cassert(mc, mc->mc_flags & C_INITIALIZED);
+
+	mp = mc->mc_pg[mc->mc_top];
+
+	if (mc->mc_db->md_flags & MDB_DUPSORT) {
+		leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+			if (op == MDB_NEXT || op == MDB_NEXT_DUP) {
+				rc = mdb_cursor_next(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_NEXT);
+				if (op != MDB_NEXT || rc != MDB_NOTFOUND) {
+					if (rc == MDB_SUCCESS)
+						MDB_GET_KEY(leaf, key);
+					return rc;
+				}
+			}
+		} else {
+			mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
+			if (op == MDB_NEXT_DUP)
+				return MDB_NOTFOUND;
+		}
+	}
+
+	DPRINTF(("cursor_next: top page is %"Z"u in cursor %p",
+		mdb_dbg_pgno(mp), (void *) mc));
+	if (mc->mc_flags & C_DEL)
+		goto skip;
+
+	if (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mp)) {
+		DPUTS("=====> move to next sibling page");
+		if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {
+			mc->mc_flags |= C_EOF;
+			return rc;
+		}
+		mp = mc->mc_pg[mc->mc_top];
+		DPRINTF(("next page is %"Z"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
+	} else
+		mc->mc_ki[mc->mc_top]++;
+
+skip:
+	DPRINTF(("==> cursor points to page %"Z"u with %u keys, key index %u",
+	    mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
+
+	if (IS_LEAF2(mp)) {
+		key->mv_size = mc->mc_db->md_pad;
+		key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
+		return MDB_SUCCESS;
+	}
+
+	mdb_cassert(mc, IS_LEAF(mp));
+	leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
+
+	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+		mdb_xcursor_init1(mc, leaf);
+	}
+	if (data) {
+		if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
+			return rc;
+
+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+			rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
+			if (rc != MDB_SUCCESS)
+				return rc;
+		}
+	}
+
+	MDB_GET_KEY(leaf, key);
+	return MDB_SUCCESS;
+}
+
+/** Move the cursor to the previous data item. */
+static int
+mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
+{
+	MDB_page	*mp;
+	MDB_node	*leaf;
+	int rc;
+
+	mdb_cassert(mc, mc->mc_flags & C_INITIALIZED);
+
+	mp = mc->mc_pg[mc->mc_top];
+
+	if (mc->mc_db->md_flags & MDB_DUPSORT) {
+		leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+			if (op == MDB_PREV || op == MDB_PREV_DUP) {
+				rc = mdb_cursor_prev(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_PREV);
+				if (op != MDB_PREV || rc != MDB_NOTFOUND) {
+					if (rc == MDB_SUCCESS) {
+						MDB_GET_KEY(leaf, key);
+						mc->mc_flags &= ~C_EOF;
+					}
+					return rc;
+				}
+			} else {
+				mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
+				if (op == MDB_PREV_DUP)
+					return MDB_NOTFOUND;
+			}
+		}
+	}
+
+	DPRINTF(("cursor_prev: top page is %"Z"u in cursor %p",
+		mdb_dbg_pgno(mp), (void *) mc));
+
+	if (mc->mc_ki[mc->mc_top] == 0)  {
+		DPUTS("=====> move to prev sibling page");
+		if ((rc = mdb_cursor_sibling(mc, 0)) != MDB_SUCCESS) {
+			return rc;
+		}
+		mp = mc->mc_pg[mc->mc_top];
+		mc->mc_ki[mc->mc_top] = NUMKEYS(mp) - 1;
+		DPRINTF(("prev page is %"Z"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
+	} else
+		mc->mc_ki[mc->mc_top]--;
+
+	mc->mc_flags &= ~C_EOF;
+
+	DPRINTF(("==> cursor points to page %"Z"u with %u keys, key index %u",
+	    mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
+
+	if (IS_LEAF2(mp)) {
+		key->mv_size = mc->mc_db->md_pad;
+		key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
+		return MDB_SUCCESS;
+	}
+
+	mdb_cassert(mc, IS_LEAF(mp));
+	leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
+
+	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+		mdb_xcursor_init1(mc, leaf);
+	}
+	if (data) {
+		if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
+			return rc;
+
+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+			rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
+			if (rc != MDB_SUCCESS)
+				return rc;
+		}
+	}
+
+	MDB_GET_KEY(leaf, key);
+	return MDB_SUCCESS;
+}
+
+/** Set the cursor on a specific data item. */
+static int
+mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
+    MDB_cursor_op op, int *exactp)
+{
+	int		 rc;
+	MDB_page	*mp;
+	MDB_node	*leaf = NULL;
+	DKBUF;
+
+	if (key->mv_size == 0)
+		return MDB_BAD_VALSIZE;
+
+	if (mc->mc_xcursor)
+		mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
+
+	/* See if we're already on the right page */
+	if (mc->mc_flags & C_INITIALIZED) {
+		MDB_val nodekey;
+
+		mp = mc->mc_pg[mc->mc_top];
+		if (!NUMKEYS(mp)) {
+			mc->mc_ki[mc->mc_top] = 0;
+			return MDB_NOTFOUND;
+		}
+		if (mp->mp_flags & P_LEAF2) {
+			nodekey.mv_size = mc->mc_db->md_pad;
+			nodekey.mv_data = LEAF2KEY(mp, 0, nodekey.mv_size);
+		} else {
+			leaf = NODEPTR(mp, 0);
+			MDB_GET_KEY2(leaf, nodekey);
+		}
+		rc = mc->mc_dbx->md_cmp(key, &nodekey);
+		if (rc == 0) {
+			/* Probably happens rarely, but first node on the page
+			 * was the one we wanted.
+			 */
+			mc->mc_ki[mc->mc_top] = 0;
+			if (exactp)
+				*exactp = 1;
+			goto set1;
+		}
+		if (rc > 0) {
+			unsigned int i;
+			unsigned int nkeys = NUMKEYS(mp);
+			if (nkeys > 1) {
+				if (mp->mp_flags & P_LEAF2) {
+					nodekey.mv_data = LEAF2KEY(mp,
+						 nkeys-1, nodekey.mv_size);
+				} else {
+					leaf = NODEPTR(mp, nkeys-1);
+					MDB_GET_KEY2(leaf, nodekey);
+				}
+				rc = mc->mc_dbx->md_cmp(key, &nodekey);
+				if (rc == 0) {
+					/* last node was the one we wanted */
+					mc->mc_ki[mc->mc_top] = nkeys-1;
+					if (exactp)
+						*exactp = 1;
+					goto set1;
+				}
+				if (rc < 0) {
+					if (mc->mc_ki[mc->mc_top] < NUMKEYS(mp)) {
+						/* This is definitely the right page, skip search_page */
+						if (mp->mp_flags & P_LEAF2) {
+							nodekey.mv_data = LEAF2KEY(mp,
+								 mc->mc_ki[mc->mc_top], nodekey.mv_size);
+						} else {
+							leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
+							MDB_GET_KEY2(leaf, nodekey);
+						}
+						rc = mc->mc_dbx->md_cmp(key, &nodekey);
+						if (rc == 0) {
+							/* current node was the one we wanted */
+							if (exactp)
+								*exactp = 1;
+							goto set1;
+						}
+					}
+					rc = 0;
+					goto set2;
+				}
+			}
+			/* If any parents have right-sibs, search.
+			 * Otherwise, there's nothing further.
+			 */
+			for (i=0; i<mc->mc_top; i++)
+				if (mc->mc_ki[i] <
+					NUMKEYS(mc->mc_pg[i])-1)
+					break;
+			if (i == mc->mc_top) {
+				/* There are no other pages */
+				mc->mc_ki[mc->mc_top] = nkeys;
+				return MDB_NOTFOUND;
+			}
+		}
+		if (!mc->mc_top) {
+			/* There are no other pages */
+			mc->mc_ki[mc->mc_top] = 0;
+			if (op == MDB_SET_RANGE && !exactp) {
+				rc = 0;
+				goto set1;
+			} else
+				return MDB_NOTFOUND;
+		}
+	}
+
+	rc = mdb_page_search(mc, key, 0);
+	if (rc != MDB_SUCCESS)
+		return rc;
+
+	mp = mc->mc_pg[mc->mc_top];
+	mdb_cassert(mc, IS_LEAF(mp));
+
+set2:
+	leaf = mdb_node_search(mc, key, exactp);
+	if (exactp != NULL && !*exactp) {
+		/* MDB_SET specified and not an exact match. */
+		return MDB_NOTFOUND;
+	}
+
+	if (leaf == NULL) {
+		DPUTS("===> inexact leaf not found, goto sibling");
+		if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS)
+			return rc;		/* no entries matched */
+		mp = mc->mc_pg[mc->mc_top];
+		mdb_cassert(mc, IS_LEAF(mp));
+		leaf = NODEPTR(mp, 0);
+	}
+
+set1:
+	mc->mc_flags |= C_INITIALIZED;
+	mc->mc_flags &= ~C_EOF;
+
+	if (IS_LEAF2(mp)) {
+		if (op == MDB_SET_RANGE || op == MDB_SET_KEY) {
+			key->mv_size = mc->mc_db->md_pad;
+			key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
+		}
+		return MDB_SUCCESS;
+	}
+
+	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+		mdb_xcursor_init1(mc, leaf);
+	}
+	if (data) {
+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+			if (op == MDB_SET || op == MDB_SET_KEY || op == MDB_SET_RANGE) {
+				rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
+			} else {
+				int ex2, *ex2p;
+				if (op == MDB_GET_BOTH) {
+					ex2p = &ex2;
+					ex2 = 0;
+				} else {
+					ex2p = NULL;
+				}
+				rc = mdb_cursor_set(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_SET_RANGE, ex2p);
+				if (rc != MDB_SUCCESS)
+					return rc;
+			}
+		} else if (op == MDB_GET_BOTH || op == MDB_GET_BOTH_RANGE) {
+			MDB_val d2;
+			if ((rc = mdb_node_read(mc->mc_txn, leaf, &d2)) != MDB_SUCCESS)
+				return rc;
+			rc = mc->mc_dbx->md_dcmp(data, &d2);
+			if (rc) {
+				if (op == MDB_GET_BOTH || rc > 0)
+					return MDB_NOTFOUND;
+				rc = 0;
+				*data = d2;
+			}
+
+		} else {
+			if (mc->mc_xcursor)
+				mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
+			if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
+				return rc;
+		}
+	}
+
+	/* The key already matches in all other cases */
+	if (op == MDB_SET_RANGE || op == MDB_SET_KEY)
+		MDB_GET_KEY(leaf, key);
+	DPRINTF(("==> cursor placed on key [%s]", DKEY(key)));
+
+	return rc;
+}
+
+/** Move the cursor to the first item in the database. */
+static int
+mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data)
+{
+	int		 rc;
+	MDB_node	*leaf;
+
+	if (mc->mc_xcursor)
+		mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
+
+	if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
+		rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);
+		if (rc != MDB_SUCCESS)
+			return rc;
+	}
+	mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));
+
+	leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
+	mc->mc_flags |= C_INITIALIZED;
+	mc->mc_flags &= ~C_EOF;
+
+	mc->mc_ki[mc->mc_top] = 0;
+
+	if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
+		key->mv_size = mc->mc_db->md_pad;
+		key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], 0, key->mv_size);
+		return MDB_SUCCESS;
+	}
+
+	if (data) {
+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+			mdb_xcursor_init1(mc, leaf);
+			rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
+			if (rc)
+				return rc;
+		} else {
+			if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
+				return rc;
+		}
+	}
+	MDB_GET_KEY(leaf, key);
+	return MDB_SUCCESS;
+}
+
+/** Move the cursor to the last item in the database. */
+static int
+mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data)
+{
+	int		 rc;
+	MDB_node	*leaf;
+
+	if (mc->mc_xcursor)
+		mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
+
+	if (!(mc->mc_flags & C_EOF)) {
+
+		if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
+			rc = mdb_page_search(mc, NULL, MDB_PS_LAST);
+			if (rc != MDB_SUCCESS)
+				return rc;
+		}
+		mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));
+
+	}
+	mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]) - 1;
+	mc->mc_flags |= C_INITIALIZED|C_EOF;
+	leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
+
+	if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
+		key->mv_size = mc->mc_db->md_pad;
+		key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], key->mv_size);
+		return MDB_SUCCESS;
+	}
+
+	if (data) {
+		if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+			mdb_xcursor_init1(mc, leaf);
+			rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
+			if (rc)
+				return rc;
+		} else {
+			if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
+				return rc;
+		}
+	}
+
+	MDB_GET_KEY(leaf, key);
+	return MDB_SUCCESS;
+}
+
+int
+mdb_cursor_get(MDB_cursor *mc, MDB_val *key, MDB_val *data,
+    MDB_cursor_op op)
+{
+	int		 rc;
+	int		 exact = 0;
+	int		 (*mfunc)(MDB_cursor *mc, MDB_val *key, MDB_val *data);
+
+	if (mc == NULL)
+		return EINVAL;
+
+	if (mc->mc_txn->mt_flags & MDB_TXN_ERROR)
+		return MDB_BAD_TXN;
+
+	switch (op) {
+	case MDB_GET_CURRENT:
+		if (!(mc->mc_flags & C_INITIALIZED)) {
+			rc = EINVAL;
+		} else {
+			MDB_page *mp = mc->mc_pg[mc->mc_top];
+			int nkeys = NUMKEYS(mp);
+			if (!nkeys || mc->mc_ki[mc->mc_top] >= nkeys) {
+				mc->mc_ki[mc->mc_top] = nkeys;
+				rc = MDB_NOTFOUND;
+				break;
+			}
+			rc = MDB_SUCCESS;
+			if (IS_LEAF2(mp)) {
+				key->mv_size = mc->mc_db->md_pad;
+				key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
+			} else {
+				MDB_node *leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
+				MDB_GET_KEY(leaf, key);
+				if (data) {
+					if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+						if (mc->mc_flags & C_DEL)
+							mdb_xcursor_init1(mc, leaf);
+						rc = mdb_cursor_get(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_GET_CURRENT);
+					} else {
+						rc = mdb_node_read(mc->mc_txn, leaf, data);
+					}
+				}
+			}
+		}
+		break;
+	case MDB_GET_BOTH:
+	case MDB_GET_BOTH_RANGE:
+		if (data == NULL) {
+			rc = EINVAL;
+			break;
+		}
+		if (mc->mc_xcursor == NULL) {
+			rc = MDB_INCOMPATIBLE;
+			break;
+		}
+		/* FALLTHRU */
+	case MDB_SET:
+	case MDB_SET_KEY:
+	case MDB_SET_RANGE:
+		if (key == NULL) {
+			rc = EINVAL;
+		} else {
+			rc = mdb_cursor_set(mc, key, data, op,
+				op == MDB_SET_RANGE ? NULL : &exact);
+		}
+		break;
+	case MDB_GET_MULTIPLE:
+		if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
+			rc = EINVAL;
+			break;
+		}
+		if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
+			rc = MDB_INCOMPATIBLE;
+			break;
+		}
+		rc = MDB_SUCCESS;
+		if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) ||
+			(mc->mc_xcursor->mx_cursor.mc_flags & C_EOF))
+			break;
+		goto fetchm;
+	case MDB_NEXT_MULTIPLE:
+		if (data == NULL) {
+			rc = EINVAL;
+			break;
+		}
+		if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
+			rc = MDB_INCOMPATIBLE;
+			break;
+		}
+		if (!(mc->mc_flags & C_INITIALIZED))
+			rc = mdb_cursor_first(mc, key, data);
+		else
+			rc = mdb_cursor_next(mc, key, data, MDB_NEXT_DUP);
+		if (rc == MDB_SUCCESS) {
+			if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
+				MDB_cursor *mx;
+fetchm:
+				mx = &mc->mc_xcursor->mx_cursor;
+				data->mv_size = NUMKEYS(mx->mc_pg[mx->mc_top]) *
+					mx->mc_db->md_pad;
+				data->mv_data = METADATA(mx->mc_pg[mx->mc_top]);
+				mx->mc_ki[mx->mc_top] = NUMKEYS(mx->mc_pg[mx->mc_top])-1;
+			} else {
+				rc = MDB_NOTFOUND;
+			}
+		}
+		break;
+	case MDB_NEXT:
+	case MDB_NEXT_DUP:
+	case MDB_NEXT_NODUP:
+		if (!(mc->mc_flags & C_INITIALIZED))
+			rc = mdb_cursor_first(mc, key, data);
+		else
+			rc = mdb_cursor_next(mc, key, data, op);
+		break;
+	case MDB_PREV:
+	case MDB_PREV_DUP:
+	case MDB_PREV_NODUP:
+		if (!(mc->mc_flags & C_INITIALIZED)) {
+			rc = mdb_cursor_last(mc, key, data);
+			if (rc)
+				break;
+			mc->mc_flags |= C_INITIALIZED;
+			mc->mc_ki[mc->mc_top]++;
+		}
+		rc = mdb_cursor_prev(mc, key, data, op);
+		break;
+	case MDB_FIRST:
+		rc = mdb_cursor_first(mc, key, data);
+		break;
+	case MDB_FIRST_DUP:
+		mfunc = mdb_cursor_first;
+	mmove:
+		if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
+			rc = EINVAL;
+			break;
+		}
+		if (mc->mc_xcursor == NULL) {
+			rc = MDB_INCOMPATIBLE;
+			break;
+		}
+		{
+			MDB_node *leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
+			if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+				MDB_GET_KEY(leaf, key);
+				rc = mdb_node_read(mc->mc_txn, leaf, data);
+				break;
+			}
+		}
+		if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
+			rc = EINVAL;
+			break;
+		}
+		rc = mfunc(&mc->mc_xcursor->mx_cursor, data, NULL);
+		break;
+	case MDB_LAST:
+		rc = mdb_cursor_last(mc, key, data);
+		break;
+	case MDB_LAST_DUP:
+		mfunc = mdb_cursor_last;
+		goto mmove;
+	default:
+		DPRINTF(("unhandled/unimplemented cursor operation %u", op));
+		rc = EINVAL;
+		break;
+	}
+
+	if (mc->mc_flags & C_DEL)
+		mc->mc_flags ^= C_DEL;
+
+	return rc;
+}
+
+/** Touch all the pages in the cursor stack. Set mc_top.
+ *	Makes sure all the pages are writable, before attempting a write operation.
+ * @param[in] mc The cursor to operate on.
+ */
+static int
+mdb_cursor_touch(MDB_cursor *mc)
+{
+	int rc = MDB_SUCCESS;
+
+	if (mc->mc_dbi > MAIN_DBI && !(*mc->mc_dbflag & DB_DIRTY)) {
+		MDB_cursor mc2;
+		MDB_xcursor mcx;
+		if (TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))
+			return MDB_BAD_DBI;
+		mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, &mcx);
+		rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, MDB_PS_MODIFY);
+		if (rc)
+			 return rc;
+		*mc->mc_dbflag |= DB_DIRTY;
+	}
+	mc->mc_top = 0;
+	if (mc->mc_snum) {
+		do {
+			rc = mdb_page_touch(mc);
+		} while (!rc && ++(mc->mc_top) < mc->mc_snum);
+		mc->mc_top = mc->mc_snum-1;
+	}
+	return rc;
+}
+
+/** Do not spill pages to disk if txn is getting full, may fail instead */
+#define MDB_NOSPILL	0x8000
+
+int
+mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
+    unsigned int flags)
+{
+	enum { MDB_NO_ROOT = MDB_LAST_ERRCODE+10 }; /* internal code */
+	MDB_env		*env;
+	MDB_node	*leaf = NULL;
+	MDB_page	*fp, *mp;
+	uint16_t	fp_flags;
+	MDB_val		xdata, *rdata, dkey, olddata;
+	MDB_db dummy;
+	int do_sub = 0, insert_key, insert_data;
+	unsigned int mcount = 0, dcount = 0, nospill;
+	size_t nsize;
+	int rc, rc2;
+	unsigned int nflags;
+	DKBUF;
+
+	if (mc == NULL || key == NULL)
+		return EINVAL;
+
+	env = mc->mc_txn->mt_env;
+
+	/* Check this first so counter will always be zero on any
+	 * early failures.
+	 */
+	if (flags & MDB_MULTIPLE) {
+		dcount = data[1].mv_size;
+		data[1].mv_size = 0;
+		if (!F_ISSET(mc->mc_db->md_flags, MDB_DUPFIXED))
+			return MDB_INCOMPATIBLE;
+	}
+
+	nospill = flags & MDB_NOSPILL;
+	flags &= ~MDB_NOSPILL;
+
+	if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_ERROR))
+		return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
+
+	if (key->mv_size-1 >= ENV_MAXKEY(env))
+		return MDB_BAD_VALSIZE;
+
+#if SIZE_MAX > MAXDATASIZE
+	if (data->mv_size > ((mc->mc_db->md_flags & MDB_DUPSORT) ? ENV_MAXKEY(env) : MAXDATASIZE))
+		return MDB_BAD_VALSIZE;
+#else
+	if ((mc->mc_db->md_flags & MDB_DUPSORT) && data->mv_size > ENV_MAXKEY(env))
+		return MDB_BAD_VALSIZE;
+#endif
+
+	DPRINTF(("==> put db %d key [%s], size %"Z"u, data size %"Z"u",
+		DDBI(mc), DKEY(key), key ? key->mv_size : 0, data->mv_size));
+
+	dkey.mv_size = 0;
+
+	if (flags == MDB_CURRENT) {
+		if (!(mc->mc_flags & C_INITIALIZED))
+			return EINVAL;
+		rc = MDB_SUCCESS;
+	} else if (mc->mc_db->md_root == P_INVALID) {
+		/* new database, cursor has nothing to point to */
+		mc->mc_snum = 0;
+		mc->mc_top = 0;
+		mc->mc_flags &= ~C_INITIALIZED;
+		rc = MDB_NO_ROOT;
+	} else {
+		int exact = 0;
+		MDB_val d2;
+		if (flags & MDB_APPEND) {
+			MDB_val k2;
+			rc = mdb_cursor_last(mc, &k2, &d2);
+			if (rc == 0) {
+				rc = mc->mc_dbx->md_cmp(key, &k2);
+				if (rc > 0) {
+					rc = MDB_NOTFOUND;
+					mc->mc_ki[mc->mc_top]++;
+				} else {
+					/* new key is <= last key */
+					rc = MDB_KEYEXIST;
+				}
+			}
+		} else {
+			rc = mdb_cursor_set(mc, key, &d2, MDB_SET, &exact);
+		}
+		if ((flags & MDB_NOOVERWRITE) && rc == 0) {
+			DPRINTF(("duplicate key [%s]", DKEY(key)));
+			*data = d2;
+			return MDB_KEYEXIST;
+		}
+		if (rc && rc != MDB_NOTFOUND)
+			return rc;
+	}
+
+	if (mc->mc_flags & C_DEL)
+		mc->mc_flags ^= C_DEL;
+
+	/* Cursor is positioned, check for room in the dirty list */
+	if (!nospill) {
+		if (flags & MDB_MULTIPLE) {
+			rdata = &xdata;
+			xdata.mv_size = data->mv_size * dcount;
+		} else {
+			rdata = data;
+		}
+		if ((rc2 = mdb_page_spill(mc, key, rdata)))
+			return rc2;
+	}
+
+	if (rc == MDB_NO_ROOT) {
+		MDB_page *np;
+		/* new database, write a root leaf page */
+		DPUTS("allocating new root leaf page");
+		if ((rc2 = mdb_page_new(mc, P_LEAF, 1, &np))) {
+			return rc2;
+		}
+		mdb_cursor_push(mc, np);
+		mc->mc_db->md_root = np->mp_pgno;
+		mc->mc_db->md_depth++;
+		*mc->mc_dbflag |= DB_DIRTY;
+		if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED))
+			== MDB_DUPFIXED)
+			np->mp_flags |= P_LEAF2;
+		mc->mc_flags |= C_INITIALIZED;
+	} else {
+		/* make sure all cursor pages are writable */
+		rc2 = mdb_cursor_touch(mc);
+		if (rc2)
+			return rc2;
+	}
+
+	insert_key = insert_data = rc;
+	if (insert_key) {
+		/* The key does not exist */
+		DPRINTF(("inserting key at index %i", mc->mc_ki[mc->mc_top]));
+		if ((mc->mc_db->md_flags & MDB_DUPSORT) &&
+			LEAFSIZE(key, data) > env->me_nodemax)
+		{
+			/* Too big for a node, insert in sub-DB.  Set up an empty
+			 * "old sub-page" for prep_subDB to expand to a full page.
+			 */
+			fp_flags = P_LEAF|P_DIRTY;
+			fp = env->me_pbuf;
+			fp->mp_pad = data->mv_size; /* used if MDB_DUPFIXED */
+			fp->mp_lower = fp->mp_upper = (PAGEHDRSZ-PAGEBASE);
+			olddata.mv_size = PAGEHDRSZ;
+			goto prep_subDB;
+		}
+	} else {
+		/* there's only a key anyway, so this is a no-op */
+		if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
+			char *ptr;
+			unsigned int ksize = mc->mc_db->md_pad;
+			if (key->mv_size != ksize)
+				return MDB_BAD_VALSIZE;
+			ptr = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], ksize);
+			memcpy(ptr, key->mv_data, ksize);
+fix_parent:
+			/* if overwriting slot 0 of leaf, need to
+			 * update branch key if there is a parent page
+			 */
+			if (mc->mc_top && !mc->mc_ki[mc->mc_top]) {
+				unsigned short top = mc->mc_top;
+				mc->mc_top--;
+				/* slot 0 is always an empty key, find real slot */
+				while (mc->mc_top && !mc->mc_ki[mc->mc_top])
+					mc->mc_top--;
+				if (mc->mc_ki[mc->mc_top])
+					rc2 = mdb_update_key(mc, key);
+				else
+					rc2 = MDB_SUCCESS;
+				mc->mc_top = top;
+				if (rc2)
+					return rc2;
+			}
+			return MDB_SUCCESS;
+		}
+
+more:
+		leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
+		olddata.mv_size = NODEDSZ(leaf);
+		olddata.mv_data = NODEDATA(leaf);
+
+		/* DB has dups? */
+		if (F_ISSET(mc->mc_db->md_flags, MDB_DUPSORT)) {
+			/* Prepare (sub-)page/sub-DB to accept the new item,
+			 * if needed.  fp: old sub-page or a header faking
+			 * it.  mp: new (sub-)page.  offset: growth in page
+			 * size.  xdata: node data with new page or DB.
+			 */
+			unsigned	i, offset = 0;
+			mp = fp = xdata.mv_data = env->me_pbuf;
+			mp->mp_pgno = mc->mc_pg[mc->mc_top]->mp_pgno;
+
+			/* Was a single item before, must convert now */
+			if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+				/* Just overwrite the current item */
+				if (flags == MDB_CURRENT)
+					goto current;
+
+#if UINT_MAX < SIZE_MAX
+				if (mc->mc_dbx->md_dcmp == mdb_cmp_int && olddata.mv_size == sizeof(size_t))
+					mc->mc_dbx->md_dcmp = mdb_cmp_clong;
+#endif
+				/* does data match? */
+				if (!mc->mc_dbx->md_dcmp(data, &olddata)) {
+					if (flags & MDB_NODUPDATA)
+						return MDB_KEYEXIST;
+					/* overwrite it */
+					goto current;
+				}
+
+				/* Back up original data item */
+				dkey.mv_size = olddata.mv_size;
+				dkey.mv_data = memcpy(fp+1, olddata.mv_data, olddata.mv_size);
+
+				/* Make sub-page header for the dup items, with dummy body */
+				fp->mp_flags = P_LEAF|P_DIRTY|P_SUBP;
+				fp->mp_lower = (PAGEHDRSZ-PAGEBASE);
+				xdata.mv_size = PAGEHDRSZ + dkey.mv_size + data->mv_size;
+				if (mc->mc_db->md_flags & MDB_DUPFIXED) {
+					fp->mp_flags |= P_LEAF2;
+					fp->mp_pad = data->mv_size;
+					xdata.mv_size += 2 * data->mv_size;	/* leave space for 2 more */
+				} else {
+					xdata.mv_size += 2 * (sizeof(indx_t) + NODESIZE) +
+						(dkey.mv_size & 1) + (data->mv_size & 1);
+				}
+				fp->mp_upper = xdata.mv_size - PAGEBASE;
+				olddata.mv_size = xdata.mv_size; /* pretend olddata is fp */
+			} else if (leaf->mn_flags & F_SUBDATA) {
+				/* Data is on sub-DB, just store it */
+				flags |= F_DUPDATA|F_SUBDATA;
+				goto put_sub;
+			} else {
+				/* Data is on sub-page */
+				fp = olddata.mv_data;
+				switch (flags) {
+				default:
+					if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
+						offset = EVEN(NODESIZE + sizeof(indx_t) +
+							data->mv_size);
+						break;
+					}
+					offset = fp->mp_pad;
+					if (SIZELEFT(fp) < offset) {
+						offset *= 4; /* space for 4 more */
+						break;
+					}
+					/* FALLTHRU: Big enough MDB_DUPFIXED sub-page */
+				case MDB_CURRENT:
+					fp->mp_flags |= P_DIRTY;
+					COPY_PGNO(fp->mp_pgno, mp->mp_pgno);
+					mc->mc_xcursor->mx_cursor.mc_pg[0] = fp;
+					flags |= F_DUPDATA;
+					goto put_sub;
+				}
+				xdata.mv_size = olddata.mv_size + offset;
+			}
+
+			fp_flags = fp->mp_flags;
+			if (NODESIZE + NODEKSZ(leaf) + xdata.mv_size > env->me_nodemax) {
+					/* Too big for a sub-page, convert to sub-DB */
+					fp_flags &= ~P_SUBP;
+prep_subDB:
+					if (mc->mc_db->md_flags & MDB_DUPFIXED) {
+						fp_flags |= P_LEAF2;
+						dummy.md_pad = fp->mp_pad;
+						dummy.md_flags = MDB_DUPFIXED;
+						if (mc->mc_db->md_flags & MDB_INTEGERDUP)
+							dummy.md_flags |= MDB_INTEGERKEY;
+					} else {
+						dummy.md_pad = 0;
+						dummy.md_flags = 0;
+					}
+					dummy.md_depth = 1;
+					dummy.md_branch_pages = 0;
+					dummy.md_leaf_pages = 1;
+					dummy.md_overflow_pages = 0;
+					dummy.md_entries = NUMKEYS(fp);
+					xdata.mv_size = sizeof(MDB_db);
+					xdata.mv_data = &dummy;
+					if ((rc = mdb_page_alloc(mc, 1, &mp)))
+						return rc;
+					offset = env->me_psize - olddata.mv_size;
+					flags |= F_DUPDATA|F_SUBDATA;
+					dummy.md_root = mp->mp_pgno;
+			}
+			if (mp != fp) {
+				mp->mp_flags = fp_flags | P_DIRTY;
+				mp->mp_pad   = fp->mp_pad;
+				mp->mp_lower = fp->mp_lower;
+				mp->mp_upper = fp->mp_upper + offset;
+				if (fp_flags & P_LEAF2) {
+					memcpy(METADATA(mp), METADATA(fp), NUMKEYS(fp) * fp->mp_pad);
+				} else {
+					memcpy((char *)mp + mp->mp_upper + PAGEBASE, (char *)fp + fp->mp_upper + PAGEBASE,
+						olddata.mv_size - fp->mp_upper - PAGEBASE);
+					for (i=0; i<NUMKEYS(fp); i++)
+						mp->mp_ptrs[i] = fp->mp_ptrs[i] + offset;
+				}
+			}
+
+			rdata = &xdata;
+			flags |= F_DUPDATA;
+			do_sub = 1;
+			if (!insert_key)
+				mdb_node_del(mc, 0);
+			goto new_sub;
+		}
+current:
+		/* overflow page overwrites need special handling */
+		if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
+			MDB_page *omp;
+			pgno_t pg;
+			int level, ovpages, dpages = OVPAGES(data->mv_size, env->me_psize);
+
+			memcpy(&pg, olddata.mv_data, sizeof(pg));
+			if ((rc2 = mdb_page_get(mc->mc_txn, pg, &omp, &level)) != 0)
+				return rc2;
+			ovpages = omp->mp_pages;
+
+			/* Is the ov page large enough? */
+			if (ovpages >= dpages) {
+			  if (!(omp->mp_flags & P_DIRTY) &&
+				  (level || (env->me_flags & MDB_WRITEMAP)))
+			  {
+				rc = mdb_page_unspill(mc->mc_txn, omp, &omp);
+				if (rc)
+					return rc;
+				level = 0;		/* dirty in this txn or clean */
+			  }
+			  /* Is it dirty? */
+			  if (omp->mp_flags & P_DIRTY) {
+				/* yes, overwrite it. Note in this case we don't
+				 * bother to try shrinking the page if the new data
+				 * is smaller than the overflow threshold.
+				 */
+				if (level > 1) {
+					/* It is writable only in a parent txn */
+					size_t sz = (size_t) env->me_psize * ovpages, off;
+					MDB_page *np = mdb_page_malloc(mc->mc_txn, ovpages);
+					MDB_ID2 id2;
+					if (!np)
+						return ENOMEM;
+					id2.mid = pg;
+					id2.mptr = np;
+					rc2 = mdb_mid2l_insert(mc->mc_txn->mt_u.dirty_list, &id2);
+					mdb_cassert(mc, rc2 == 0);
+					if (!(flags & MDB_RESERVE)) {
+						/* Copy end of page, adjusting alignment so
+						 * compiler may copy words instead of bytes.
+						 */
+						off = (PAGEHDRSZ + data->mv_size) & -sizeof(size_t);
+						memcpy((size_t *)((char *)np + off),
+							(size_t *)((char *)omp + off), sz - off);
+						sz = PAGEHDRSZ;
+					}
+					memcpy(np, omp, sz); /* Copy beginning of page */
+					omp = np;
+				}
+				SETDSZ(leaf, data->mv_size);
+				if (F_ISSET(flags, MDB_RESERVE))
+					data->mv_data = METADATA(omp);
+				else
+					memcpy(METADATA(omp), data->mv_data, data->mv_size);
+				return MDB_SUCCESS;
+			  }
+			}
+			if ((rc2 = mdb_ovpage_free(mc, omp)) != MDB_SUCCESS)
+				return rc2;
+		} else if (data->mv_size == olddata.mv_size) {
+			/* same size, just replace it. Note that we could
+			 * also reuse this node if the new data is smaller,
+			 * but instead we opt to shrink the node in that case.
+			 */
+			if (F_ISSET(flags, MDB_RESERVE))
+				data->mv_data = olddata.mv_data;
+			else if (!(mc->mc_flags & C_SUB))
+				memcpy(olddata.mv_data, data->mv_data, data->mv_size);
+			else {
+				memcpy(NODEKEY(leaf), key->mv_data, key->mv_size);
+				goto fix_parent;
+			}
+			return MDB_SUCCESS;
+		}
+		mdb_node_del(mc, 0);
+	}
+
+	rdata = data;
+
+new_sub:
+	nflags = flags & NODE_ADD_FLAGS;
+	nsize = IS_LEAF2(mc->mc_pg[mc->mc_top]) ? key->mv_size : mdb_leaf_size(env, key, rdata);
+	if (SIZELEFT(mc->mc_pg[mc->mc_top]) < nsize) {
+		if (( flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA )
+			nflags &= ~MDB_APPEND; /* sub-page may need room to grow */
+		if (!insert_key)
+			nflags |= MDB_SPLIT_REPLACE;
+		rc = mdb_page_split(mc, key, rdata, P_INVALID, nflags);
+	} else {
+		/* There is room already in this leaf page. */
+		rc = mdb_node_add(mc, mc->mc_ki[mc->mc_top], key, rdata, 0, nflags);
+		if (rc == 0 && insert_key) {
+			/* Adjust other cursors pointing to mp */
+			MDB_cursor *m2, *m3;
+			MDB_dbi dbi = mc->mc_dbi;
+			unsigned i = mc->mc_top;
+			MDB_page *mp = mc->mc_pg[i];
+
+			for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
+				if (mc->mc_flags & C_SUB)
+					m3 = &m2->mc_xcursor->mx_cursor;
+				else
+					m3 = m2;
+				if (m3 == mc || m3->mc_snum < mc->mc_snum) continue;
+				if (m3->mc_pg[i] == mp && m3->mc_ki[i] >= mc->mc_ki[i]) {
+					m3->mc_ki[i]++;
+				}
+			}
+		}
+	}
+
+	if (rc == MDB_SUCCESS) {
+		/* Now store the actual data in the child DB. Note that we're
+		 * storing the user data in the keys field, so there are strict
+		 * size limits on dupdata. The actual data fields of the child
+		 * DB are all zero size.
+		 */
+		if (do_sub) {
+			int xflags;
+			size_t ecount;
+put_sub:
+			xdata.mv_size = 0;
+			xdata.mv_data = "";
+			leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
+			if (flags & MDB_CURRENT) {
+				xflags = MDB_CURRENT|MDB_NOSPILL;
+			} else {
+				mdb_xcursor_init1(mc, leaf);
+				xflags = (flags & MDB_NODUPDATA) ?
+					MDB_NOOVERWRITE|MDB_NOSPILL : MDB_NOSPILL;
+			}
+			/* converted, write the original data first */
+			if (dkey.mv_size) {
+				rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, &dkey, &xdata, xflags);
+				if (rc)
+					goto bad_sub;
+				{
+					/* Adjust other cursors pointing to mp */
+					MDB_cursor *m2;
+					unsigned i = mc->mc_top;
+					MDB_page *mp = mc->mc_pg[i];
+
+					for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
+						if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
+						if (!(m2->mc_flags & C_INITIALIZED)) continue;
+						if (m2->mc_pg[i] == mp && m2->mc_ki[i] == mc->mc_ki[i]) {
+							mdb_xcursor_init1(m2, leaf);
+						}
+					}
+				}
+				/* we've done our job */
+				dkey.mv_size = 0;
+			}
+			ecount = mc->mc_xcursor->mx_db.md_entries;
+			if (flags & MDB_APPENDDUP)
+				xflags |= MDB_APPEND;
+			rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, data, &xdata, xflags);
+			if (flags & F_SUBDATA) {
+				void *db = NODEDATA(leaf);
+				memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
+			}
+			insert_data = mc->mc_xcursor->mx_db.md_entries - ecount;
+		}
+		/* Increment count unless we just replaced an existing item. */
+		if (insert_data)
+			mc->mc_db->md_entries++;
+		if (insert_key) {
+			/* Invalidate txn if we created an empty sub-DB */
+			if (rc)
+				goto bad_sub;
+			/* If we succeeded and the key didn't exist before,
+			 * make sure the cursor is marked valid.
+			 */
+			mc->mc_flags |= C_INITIALIZED;
+		}
+		if (flags & MDB_MULTIPLE) {
+			if (!rc) {
+				mcount++;
+				/* let caller know how many succeeded, if any */
+				data[1].mv_size = mcount;
+				if (mcount < dcount) {
+					data[0].mv_data = (char *)data[0].mv_data + data[0].mv_size;
+					insert_key = insert_data = 0;
+					goto more;
+				}
+			}
+		}
+		return rc;
+bad_sub:
+		if (rc == MDB_KEYEXIST)	/* should not happen, we deleted that item */
+			rc = MDB_CORRUPTED;
+	}
+	mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
+	return rc;
+}
+
+int
+mdb_cursor_del(MDB_cursor *mc, unsigned int flags)
+{
+	MDB_node	*leaf;
+	MDB_page	*mp;
+	int rc;
+
+	if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_ERROR))
+		return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
+
+	if (!(mc->mc_flags & C_INITIALIZED))
+		return EINVAL;
+
+	if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mc->mc_pg[mc->mc_top]))
+		return MDB_NOTFOUND;
+
+	if (!(flags & MDB_NOSPILL) && (rc = mdb_page_spill(mc, NULL, NULL)))
+		return rc;
+
+	rc = mdb_cursor_touch(mc);
+	if (rc)
+		return rc;
+
+	mp = mc->mc_pg[mc->mc_top];
+	if (IS_LEAF2(mp))
+		goto del_key;
+	leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
+
+	if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+		if (flags & MDB_NODUPDATA) {
+			/* mdb_cursor_del0() will subtract the final entry */
+			mc->mc_db->md_entries -= mc->mc_xcursor->mx_db.md_entries - 1;
+		} else {
+			if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {
+				mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
+			}
+			rc = mdb_cursor_del(&mc->mc_xcursor->mx_cursor, MDB_NOSPILL);
+			if (rc)
+				return rc;
+			/* If sub-DB still has entries, we're done */
+			if (mc->mc_xcursor->mx_db.md_entries) {
+				if (leaf->mn_flags & F_SUBDATA) {
+					/* update subDB info */
+					void *db = NODEDATA(leaf);
+					memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
+				} else {
+					MDB_cursor *m2;
+					/* shrink fake page */
+					mdb_node_shrink(mp, mc->mc_ki[mc->mc_top]);
+					leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
+					mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
+					/* fix other sub-DB cursors pointed at this fake page */
+					for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
+						if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
+						if (m2->mc_pg[mc->mc_top] == mp &&
+							m2->mc_ki[mc->mc_top] == mc->mc_ki[mc->mc_top])
+							m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
+					}
+				}
+				mc->mc_db->md_entries--;
+				mc->mc_flags |= C_DEL;
+				return rc;
+			}
+			/* otherwise fall thru and delete the sub-DB */
+		}
+
+		if (leaf->mn_flags & F_SUBDATA) {
+			/* add all the child DB's pages to the free list */
+			rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
+			if (rc)
+				goto fail;
+		}
+	}
+
+	/* add overflow pages to free list */
+	if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
+		MDB_page *omp;
+		pgno_t pg;
+
+		memcpy(&pg, NODEDATA(leaf), sizeof(pg));
+		if ((rc = mdb_page_get(mc->mc_txn, pg, &omp, NULL)) ||
+			(rc = mdb_ovpage_free(mc, omp)))
+			goto fail;
+	}
+
+del_key:
+	return mdb_cursor_del0(mc);
+
+fail:
+	mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
+	return rc;
+}
+
+/** Allocate and initialize new pages for a database.
+ * @param[in] mc a cursor on the database being added to.
+ * @param[in] flags flags defining what type of page is being allocated.
+ * @param[in] num the number of pages to allocate. This is usually 1,
+ * unless allocating overflow pages for a large record.
+ * @param[out] mp Address of a page, or NULL on failure.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp)
+{
+	MDB_page	*np;
+	int rc;
+
+	if ((rc = mdb_page_alloc(mc, num, &np)))
+		return rc;
+	DPRINTF(("allocated new mpage %"Z"u, page size %u",
+	    np->mp_pgno, mc->mc_txn->mt_env->me_psize));
+	np->mp_flags = flags | P_DIRTY;
+	np->mp_lower = (PAGEHDRSZ-PAGEBASE);
+	np->mp_upper = mc->mc_txn->mt_env->me_psize - PAGEBASE;
+
+	if (IS_BRANCH(np))
+		mc->mc_db->md_branch_pages++;
+	else if (IS_LEAF(np))
+		mc->mc_db->md_leaf_pages++;
+	else if (IS_OVERFLOW(np)) {
+		mc->mc_db->md_overflow_pages += num;
+		np->mp_pages = num;
+	}
+	*mp = np;
+
+	return 0;
+}
+
+/** Calculate the size of a leaf node.
+ * The size depends on the environment's page size; if a data item
+ * is too large it will be put onto an overflow page and the node
+ * size will only include the key and not the data. Sizes are always
+ * rounded up to an even number of bytes, to guarantee 2-byte alignment
+ * of the #MDB_node headers.
+ * @param[in] env The environment handle.
+ * @param[in] key The key for the node.
+ * @param[in] data The data for the node.
+ * @return The number of bytes needed to store the node.
+ */
+static size_t
+mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data)
+{
+	size_t		 sz;
+
+	sz = LEAFSIZE(key, data);
+	if (sz > env->me_nodemax) {
+		/* put on overflow page */
+		sz -= data->mv_size - sizeof(pgno_t);
+	}
+
+	return EVEN(sz + sizeof(indx_t));
+}
+
+/** Calculate the size of a branch node.
+ * The size should depend on the environment's page size but since
+ * we currently don't support spilling large keys onto overflow
+ * pages, it's simply the size of the #MDB_node header plus the
+ * size of the key. Sizes are always rounded up to an even number
+ * of bytes, to guarantee 2-byte alignment of the #MDB_node headers.
+ * @param[in] env The environment handle.
+ * @param[in] key The key for the node.
+ * @return The number of bytes needed to store the node.
+ */
+static size_t
+mdb_branch_size(MDB_env *env, MDB_val *key)
+{
+	size_t		 sz;
+
+	sz = INDXSIZE(key);
+	if (sz > env->me_nodemax) {
+		/* put on overflow page */
+		/* not implemented */
+		/* sz -= key->size - sizeof(pgno_t); */
+	}
+
+	return sz + sizeof(indx_t);
+}
+
+/** Add a node to the page pointed to by the cursor.
+ * @param[in] mc The cursor for this operation.
+ * @param[in] indx The index on the page where the new node should be added.
+ * @param[in] key The key for the new node.
+ * @param[in] data The data for the new node, if any.
+ * @param[in] pgno The page number, if adding a branch node.
+ * @param[in] flags Flags for the node.
+ * @return 0 on success, non-zero on failure. Possible errors are:
+ * <ul>
+ *	<li>ENOMEM - failed to allocate overflow pages for the node.
+ *	<li>MDB_PAGE_FULL - there is insufficient room in the page. This error
+ *	should never happen since all callers already calculate the
+ *	page's free space before calling this function.
+ * </ul>
+ */
+static int
+mdb_node_add(MDB_cursor *mc, indx_t indx,
+    MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags)
+{
+	unsigned int	 i;
+	size_t		 node_size = NODESIZE;
+	ssize_t		 room;
+	indx_t		 ofs;
+	MDB_node	*node;
+	MDB_page	*mp = mc->mc_pg[mc->mc_top];
+	MDB_page	*ofp = NULL;		/* overflow page */
+	DKBUF;
+
+	mdb_cassert(mc, mp->mp_upper >= mp->mp_lower);
+
+	DPRINTF(("add to %s %spage %"Z"u index %i, data size %"Z"u key size %"Z"u [%s]",
+	    IS_LEAF(mp) ? "leaf" : "branch",
+		IS_SUBP(mp) ? "sub-" : "",
+		mdb_dbg_pgno(mp), indx, data ? data->mv_size : 0,
+		key ? key->mv_size : 0, key ? DKEY(key) : "null"));
+
+	if (IS_LEAF2(mp)) {
+		/* Move higher keys up one slot. */
+		int ksize = mc->mc_db->md_pad, dif;
+		char *ptr = LEAF2KEY(mp, indx, ksize);
+		dif = NUMKEYS(mp) - indx;
+		if (dif > 0)
+			memmove(ptr+ksize, ptr, dif*ksize);
+		/* insert new key */
+		memcpy(ptr, key->mv_data, ksize);
+
+		/* Just using these for counting */
+		mp->mp_lower += sizeof(indx_t);
+		mp->mp_upper -= ksize - sizeof(indx_t);
+		return MDB_SUCCESS;
+	}
+
+	room = (ssize_t)SIZELEFT(mp) - (ssize_t)sizeof(indx_t);
+	if (key != NULL)
+		node_size += key->mv_size;
+	if (IS_LEAF(mp)) {
+		mdb_cassert(mc, data);
+		if (F_ISSET(flags, F_BIGDATA)) {
+			/* Data already on overflow page. */
+			node_size += sizeof(pgno_t);
+		} else if (node_size + data->mv_size > mc->mc_txn->mt_env->me_nodemax) {
+			int ovpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
+			int rc;
+			/* Put data on overflow page. */
+			DPRINTF(("data size is %"Z"u, node would be %"Z"u, put data on overflow page",
+			    data->mv_size, node_size+data->mv_size));
+			node_size = EVEN(node_size + sizeof(pgno_t));
+			if ((ssize_t)node_size > room)
+				goto full;
+			if ((rc = mdb_page_new(mc, P_OVERFLOW, ovpages, &ofp)))
+				return rc;
+			DPRINTF(("allocated overflow page %"Z"u", ofp->mp_pgno));
+			flags |= F_BIGDATA;
+			goto update;
+		} else {
+			node_size += data->mv_size;
+		}
+	}
+	node_size = EVEN(node_size);
+	if ((ssize_t)node_size > room)
+		goto full;
+
+update:
+	/* Move higher pointers up one slot. */
+	for (i = NUMKEYS(mp); i > indx; i--)
+		mp->mp_ptrs[i] = mp->mp_ptrs[i - 1];
+
+	/* Adjust free space offsets. */
+	ofs = mp->mp_upper - node_size;
+	mdb_cassert(mc, ofs >= mp->mp_lower + sizeof(indx_t));
+	mp->mp_ptrs[indx] = ofs;
+	mp->mp_upper = ofs;
+	mp->mp_lower += sizeof(indx_t);
+
+	/* Write the node data. */
+	node = NODEPTR(mp, indx);
+	node->mn_ksize = (key == NULL) ? 0 : key->mv_size;
+	node->mn_flags = flags;
+	if (IS_LEAF(mp))
+		SETDSZ(node,data->mv_size);
+	else
+		SETPGNO(node,pgno);
+
+	if (key)
+		memcpy(NODEKEY(node), key->mv_data, key->mv_size);
+
+	if (IS_LEAF(mp)) {
+		mdb_cassert(mc, key);
+		if (ofp == NULL) {
+			if (F_ISSET(flags, F_BIGDATA))
+				memcpy(node->mn_data + key->mv_size, data->mv_data,
+				    sizeof(pgno_t));
+			else if (F_ISSET(flags, MDB_RESERVE))
+				data->mv_data = node->mn_data + key->mv_size;
+			else
+				memcpy(node->mn_data + key->mv_size, data->mv_data,
+				    data->mv_size);
+		} else {
+			memcpy(node->mn_data + key->mv_size, &ofp->mp_pgno,
+			    sizeof(pgno_t));
+			if (F_ISSET(flags, MDB_RESERVE))
+				data->mv_data = METADATA(ofp);
+			else
+				memcpy(METADATA(ofp), data->mv_data, data->mv_size);
+		}
+	}
+
+	return MDB_SUCCESS;
+
+full:
+	DPRINTF(("not enough room in page %"Z"u, got %u ptrs",
+		mdb_dbg_pgno(mp), NUMKEYS(mp)));
+	DPRINTF(("upper-lower = %u - %u = %"Z"d", mp->mp_upper,mp->mp_lower,room));
+	DPRINTF(("node size = %"Z"u", node_size));
+	mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
+	return MDB_PAGE_FULL;
+}
+
+/** Delete the specified node from a page.
+ * @param[in] mc Cursor pointing to the node to delete.
+ * @param[in] ksize The size of a node. Only used if the page is
+ * part of a #MDB_DUPFIXED database.
+ */
+static void
+mdb_node_del(MDB_cursor *mc, int ksize)
+{
+	MDB_page *mp = mc->mc_pg[mc->mc_top];
+	indx_t	indx = mc->mc_ki[mc->mc_top];
+	unsigned int	 sz;
+	indx_t		 i, j, numkeys, ptr;
+	MDB_node	*node;
+	char		*base;
+
+	DPRINTF(("delete node %u on %s page %"Z"u", indx,
+	    IS_LEAF(mp) ? "leaf" : "branch", mdb_dbg_pgno(mp)));
+	numkeys = NUMKEYS(mp);
+	mdb_cassert(mc, indx < numkeys);
+
+	if (IS_LEAF2(mp)) {
+		int x = numkeys - 1 - indx;
+		base = LEAF2KEY(mp, indx, ksize);
+		if (x)
+			memmove(base, base + ksize, x * ksize);
+		mp->mp_lower -= sizeof(indx_t);
+		mp->mp_upper += ksize - sizeof(indx_t);
+		return;
+	}
+
+	node = NODEPTR(mp, indx);
+	sz = NODESIZE + node->mn_ksize;
+	if (IS_LEAF(mp)) {
+		if (F_ISSET(node->mn_flags, F_BIGDATA))
+			sz += sizeof(pgno_t);
+		else
+			sz += NODEDSZ(node);
+	}
+	sz = EVEN(sz);
+
+	ptr = mp->mp_ptrs[indx];
+	for (i = j = 0; i < numkeys; i++) {
+		if (i != indx) {
+			mp->mp_ptrs[j] = mp->mp_ptrs[i];
+			if (mp->mp_ptrs[i] < ptr)
+				mp->mp_ptrs[j] += sz;
+			j++;
+		}
+	}
+
+	base = (char *)mp + mp->mp_upper + PAGEBASE;
+	memmove(base + sz, base, ptr - mp->mp_upper);
+
+	mp->mp_lower -= sizeof(indx_t);
+	mp->mp_upper += sz;
+}
+
+/** Compact the main page after deleting a node on a subpage.
+ * @param[in] mp The main page to operate on.
+ * @param[in] indx The index of the subpage on the main page.
+ */
+static void
+mdb_node_shrink(MDB_page *mp, indx_t indx)
+{
+	MDB_node *node;
+	MDB_page *sp, *xp;
+	char *base;
+	int nsize, delta;
+	indx_t		 i, numkeys, ptr;
+
+	node = NODEPTR(mp, indx);
+	sp = (MDB_page *)NODEDATA(node);
+	delta = SIZELEFT(sp);
+	xp = (MDB_page *)((char *)sp + delta);
+
+	/* shift subpage upward */
+	if (IS_LEAF2(sp)) {
+		nsize = NUMKEYS(sp) * sp->mp_pad;
+		if (nsize & 1)
+			return;		/* do not make the node uneven-sized */
+		memmove(METADATA(xp), METADATA(sp), nsize);
+	} else {
+		int i;
+		numkeys = NUMKEYS(sp);
+		for (i=numkeys-1; i>=0; i--)
+			xp->mp_ptrs[i] = sp->mp_ptrs[i] - delta;
+	}
+	xp->mp_upper = sp->mp_lower;
+	xp->mp_lower = sp->mp_lower;
+	xp->mp_flags = sp->mp_flags;
+	xp->mp_pad = sp->mp_pad;
+	COPY_PGNO(xp->mp_pgno, mp->mp_pgno);
+
+	nsize = NODEDSZ(node) - delta;
+	SETDSZ(node, nsize);
+
+	/* shift lower nodes upward */
+	ptr = mp->mp_ptrs[indx];
+	numkeys = NUMKEYS(mp);
+	for (i = 0; i < numkeys; i++) {
+		if (mp->mp_ptrs[i] <= ptr)
+			mp->mp_ptrs[i] += delta;
+	}
+
+	base = (char *)mp + mp->mp_upper + PAGEBASE;
+	memmove(base + delta, base, ptr - mp->mp_upper + NODESIZE + NODEKSZ(node));
+	mp->mp_upper += delta;
+}
+
+/** Initial setup of a sorted-dups cursor.
+ * Sorted duplicates are implemented as a sub-database for the given key.
+ * The duplicate data items are actually keys of the sub-database.
+ * Operations on the duplicate data items are performed using a sub-cursor
+ * initialized when the sub-database is first accessed. This function does
+ * the preliminary setup of the sub-cursor, filling in the fields that
+ * depend only on the parent DB.
+ * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
+ */
+static void
+mdb_xcursor_init0(MDB_cursor *mc)
+{
+	MDB_xcursor *mx = mc->mc_xcursor;
+
+	mx->mx_cursor.mc_xcursor = NULL;
+	mx->mx_cursor.mc_txn = mc->mc_txn;
+	mx->mx_cursor.mc_db = &mx->mx_db;
+	mx->mx_cursor.mc_dbx = &mx->mx_dbx;
+	mx->mx_cursor.mc_dbi = mc->mc_dbi;
+	mx->mx_cursor.mc_dbflag = &mx->mx_dbflag;
+	mx->mx_cursor.mc_snum = 0;
+	mx->mx_cursor.mc_top = 0;
+	mx->mx_cursor.mc_flags = C_SUB;
+	mx->mx_dbx.md_name.mv_size = 0;
+	mx->mx_dbx.md_name.mv_data = NULL;
+	mx->mx_dbx.md_cmp = mc->mc_dbx->md_dcmp;
+	mx->mx_dbx.md_dcmp = NULL;
+	mx->mx_dbx.md_rel = mc->mc_dbx->md_rel;
+}
+
+/** Final setup of a sorted-dups cursor.
+ *	Sets up the fields that depend on the data from the main cursor.
+ * @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
+ * @param[in] node The data containing the #MDB_db record for the
+ * sorted-dup database.
+ */
+static void
+mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
+{
+	MDB_xcursor *mx = mc->mc_xcursor;
+
+	if (node->mn_flags & F_SUBDATA) {
+		memcpy(&mx->mx_db, NODEDATA(node), sizeof(MDB_db));
+		mx->mx_cursor.mc_pg[0] = 0;
+		mx->mx_cursor.mc_snum = 0;
+		mx->mx_cursor.mc_top = 0;
+		mx->mx_cursor.mc_flags = C_SUB;
+	} else {
+		MDB_page *fp = NODEDATA(node);
+		mx->mx_db.md_pad = mc->mc_pg[mc->mc_top]->mp_pad;
+		mx->mx_db.md_flags = 0;
+		mx->mx_db.md_depth = 1;
+		mx->mx_db.md_branch_pages = 0;
+		mx->mx_db.md_leaf_pages = 1;
+		mx->mx_db.md_overflow_pages = 0;
+		mx->mx_db.md_entries = NUMKEYS(fp);
+		COPY_PGNO(mx->mx_db.md_root, fp->mp_pgno);
+		mx->mx_cursor.mc_snum = 1;
+		mx->mx_cursor.mc_top = 0;
+		mx->mx_cursor.mc_flags = C_INITIALIZED|C_SUB;
+		mx->mx_cursor.mc_pg[0] = fp;
+		mx->mx_cursor.mc_ki[0] = 0;
+		if (mc->mc_db->md_flags & MDB_DUPFIXED) {
+			mx->mx_db.md_flags = MDB_DUPFIXED;
+			mx->mx_db.md_pad = fp->mp_pad;
+			if (mc->mc_db->md_flags & MDB_INTEGERDUP)
+				mx->mx_db.md_flags |= MDB_INTEGERKEY;
+		}
+	}
+	DPRINTF(("Sub-db -%u root page %"Z"u", mx->mx_cursor.mc_dbi,
+		mx->mx_db.md_root));
+	mx->mx_dbflag = DB_VALID|DB_DIRTY; /* DB_DIRTY guides mdb_cursor_touch */
+#if UINT_MAX < SIZE_MAX
+	if (mx->mx_dbx.md_cmp == mdb_cmp_int && mx->mx_db.md_pad == sizeof(size_t))
+		mx->mx_dbx.md_cmp = mdb_cmp_clong;
+#endif
+}
+
+/** Initialize a cursor for a given transaction and database. */
+static void
+mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
+{
+	mc->mc_next = NULL;
+	mc->mc_backup = NULL;
+	mc->mc_dbi = dbi;
+	mc->mc_txn = txn;
+	mc->mc_db = &txn->mt_dbs[dbi];
+	mc->mc_dbx = &txn->mt_dbxs[dbi];
+	mc->mc_dbflag = &txn->mt_dbflags[dbi];
+	mc->mc_snum = 0;
+	mc->mc_top = 0;
+	mc->mc_pg[0] = 0;
+	mc->mc_flags = 0;
+	if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
+		mdb_tassert(txn, mx != NULL);
+		mc->mc_xcursor = mx;
+		mdb_xcursor_init0(mc);
+	} else {
+		mc->mc_xcursor = NULL;
+	}
+	if (*mc->mc_dbflag & DB_STALE) {
+		mdb_page_search(mc, NULL, MDB_PS_ROOTONLY);
+	}
+}
+
+int
+mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
+{
+	MDB_cursor	*mc;
+	size_t size = sizeof(MDB_cursor);
+
+	if (!ret || !TXN_DBI_EXIST(txn, dbi))
+		return EINVAL;
+
+	if (txn->mt_flags & MDB_TXN_ERROR)
+		return MDB_BAD_TXN;
+
+	/* Allow read access to the freelist */
+	if (!dbi && !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
+		return EINVAL;
+
+	if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT)
+		size += sizeof(MDB_xcursor);
+
+	if ((mc = malloc(size)) != NULL) {
+		mdb_cursor_init(mc, txn, dbi, (MDB_xcursor *)(mc + 1));
+		if (txn->mt_cursors) {
+			mc->mc_next = txn->mt_cursors[dbi];
+			txn->mt_cursors[dbi] = mc;
+			mc->mc_flags |= C_UNTRACK;
+		}
+	} else {
+		return ENOMEM;
+	}
+
+	*ret = mc;
+
+	return MDB_SUCCESS;
+}
+
+int
+mdb_cursor_renew(MDB_txn *txn, MDB_cursor *mc)
+{
+	if (!mc || !TXN_DBI_EXIST(txn, mc->mc_dbi))
+		return EINVAL;
+
+	if ((mc->mc_flags & C_UNTRACK) || txn->mt_cursors)
+		return EINVAL;
+
+	if (txn->mt_flags & MDB_TXN_ERROR)
+		return MDB_BAD_TXN;
+
+	mdb_cursor_init(mc, txn, mc->mc_dbi, mc->mc_xcursor);
+	return MDB_SUCCESS;
+}
+
+/* Return the count of duplicate data items for the current key */
+int
+mdb_cursor_count(MDB_cursor *mc, size_t *countp)
+{
+	MDB_node	*leaf;
+
+	if (mc == NULL || countp == NULL)
+		return EINVAL;
+
+	if (mc->mc_xcursor == NULL)
+		return MDB_INCOMPATIBLE;
+
+	if (mc->mc_txn->mt_flags & MDB_TXN_ERROR)
+		return MDB_BAD_TXN;
+
+	if (!(mc->mc_flags & C_INITIALIZED))
+		return EINVAL;
+
+	if (!mc->mc_snum || (mc->mc_flags & C_EOF))
+		return MDB_NOTFOUND;
+
+	leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
+	if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+		*countp = 1;
+	} else {
+		if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
+			return EINVAL;
+
+		*countp = mc->mc_xcursor->mx_db.md_entries;
+	}
+	return MDB_SUCCESS;
+}
+
+void
+mdb_cursor_close(MDB_cursor *mc)
+{
+	if (mc && !mc->mc_backup) {
+		/* remove from txn, if tracked */
+		if ((mc->mc_flags & C_UNTRACK) && mc->mc_txn->mt_cursors) {
+			MDB_cursor **prev = &mc->mc_txn->mt_cursors[mc->mc_dbi];
+			while (*prev && *prev != mc) prev = &(*prev)->mc_next;
+			if (*prev == mc)
+				*prev = mc->mc_next;
+		}
+		free(mc);
+	}
+}
+
+MDB_txn *
+mdb_cursor_txn(MDB_cursor *mc)
+{
+	if (!mc) return NULL;
+	return mc->mc_txn;
+}
+
+MDB_dbi
+mdb_cursor_dbi(MDB_cursor *mc)
+{
+	return mc->mc_dbi;
+}
+
+/** Replace the key for a branch node with a new key.
+ * @param[in] mc Cursor pointing to the node to operate on.
+ * @param[in] key The new key to use.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_update_key(MDB_cursor *mc, MDB_val *key)
+{
+	MDB_page		*mp;
+	MDB_node		*node;
+	char			*base;
+	size_t			 len;
+	int				 delta, ksize, oksize;
+	indx_t			 ptr, i, numkeys, indx;
+	DKBUF;
+
+	indx = mc->mc_ki[mc->mc_top];
+	mp = mc->mc_pg[mc->mc_top];
+	node = NODEPTR(mp, indx);
+	ptr = mp->mp_ptrs[indx];
+#if MDB_DEBUG
+	{
+		MDB_val	k2;
+		char kbuf2[DKBUF_MAXKEYSIZE*2+1];
+		k2.mv_data = NODEKEY(node);
+		k2.mv_size = node->mn_ksize;
+		DPRINTF(("update key %u (ofs %u) [%s] to [%s] on page %"Z"u",
+			indx, ptr,
+			mdb_dkey(&k2, kbuf2),
+			DKEY(key),
+			mp->mp_pgno));
+	}
+#endif
+
+	/* Sizes must be 2-byte aligned. */
+	ksize = EVEN(key->mv_size);
+	oksize = EVEN(node->mn_ksize);
+	delta = ksize - oksize;
+
+	/* Shift node contents if EVEN(key length) changed. */
+	if (delta) {
+		if (delta > 0 && SIZELEFT(mp) < delta) {
+			pgno_t pgno;
+			/* not enough space left, do a delete and split */
+			DPRINTF(("Not enough room, delta = %d, splitting...", delta));
+			pgno = NODEPGNO(node);
+			mdb_node_del(mc, 0);
+			return mdb_page_split(mc, key, NULL, pgno, MDB_SPLIT_REPLACE);
+		}
+
+		numkeys = NUMKEYS(mp);
+		for (i = 0; i < numkeys; i++) {
+			if (mp->mp_ptrs[i] <= ptr)
+				mp->mp_ptrs[i] -= delta;
+		}
+
+		base = (char *)mp + mp->mp_upper + PAGEBASE;
+		len = ptr - mp->mp_upper + NODESIZE;
+		memmove(base - delta, base, len);
+		mp->mp_upper -= delta;
+
+		node = NODEPTR(mp, indx);
+	}
+
+	/* But even if no shift was needed, update ksize */
+	if (node->mn_ksize != key->mv_size)
+		node->mn_ksize = key->mv_size;
+
+	if (key->mv_size)
+		memcpy(NODEKEY(node), key->mv_data, key->mv_size);
+
+	return MDB_SUCCESS;
+}
+
+static void
+mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst);
+
+/** Move a node from csrc to cdst.
+ */
+static int
+mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst)
+{
+	MDB_node		*srcnode;
+	MDB_val		 key, data;
+	pgno_t	srcpg;
+	MDB_cursor mn;
+	int			 rc;
+	unsigned short flags;
+
+	DKBUF;
+
+	/* Mark src and dst as dirty. */
+	if ((rc = mdb_page_touch(csrc)) ||
+	    (rc = mdb_page_touch(cdst)))
+		return rc;
+
+	if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
+		key.mv_size = csrc->mc_db->md_pad;
+		key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
+		data.mv_size = 0;
+		data.mv_data = NULL;
+		srcpg = 0;
+		flags = 0;
+	} else {
+		srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top]);
+		mdb_cassert(csrc, !((size_t)srcnode & 1));
+		srcpg = NODEPGNO(srcnode);
+		flags = srcnode->mn_flags;
+		if (csrc->mc_ki[csrc->mc_top] == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
+			unsigned int snum = csrc->mc_snum;
+			MDB_node *s2;
+			/* must find the lowest key below src */
+			rc = mdb_page_search_lowest(csrc);
+			if (rc)
+				return rc;
+			if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
+				key.mv_size = csrc->mc_db->md_pad;
+				key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
+			} else {
+				s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
+				key.mv_size = NODEKSZ(s2);
+				key.mv_data = NODEKEY(s2);
+			}
+			csrc->mc_snum = snum--;
+			csrc->mc_top = snum;
+		} else {
+			key.mv_size = NODEKSZ(srcnode);
+			key.mv_data = NODEKEY(srcnode);
+		}
+		data.mv_size = NODEDSZ(srcnode);
+		data.mv_data = NODEDATA(srcnode);
+	}
+	if (IS_BRANCH(cdst->mc_pg[cdst->mc_top]) && cdst->mc_ki[cdst->mc_top] == 0) {
+		unsigned int snum = cdst->mc_snum;
+		MDB_node *s2;
+		MDB_val bkey;
+		/* must find the lowest key below dst */
+		mdb_cursor_copy(cdst, &mn);
+		rc = mdb_page_search_lowest(&mn);
+		if (rc)
+			return rc;
+		if (IS_LEAF2(mn.mc_pg[mn.mc_top])) {
+			bkey.mv_size = mn.mc_db->md_pad;
+			bkey.mv_data = LEAF2KEY(mn.mc_pg[mn.mc_top], 0, bkey.mv_size);
+		} else {
+			s2 = NODEPTR(mn.mc_pg[mn.mc_top], 0);
+			bkey.mv_size = NODEKSZ(s2);
+			bkey.mv_data = NODEKEY(s2);
+		}
+		mn.mc_snum = snum--;
+		mn.mc_top = snum;
+		mn.mc_ki[snum] = 0;
+		rc = mdb_update_key(&mn, &bkey);
+		if (rc)
+			return rc;
+	}
+
+	DPRINTF(("moving %s node %u [%s] on page %"Z"u to node %u on page %"Z"u",
+	    IS_LEAF(csrc->mc_pg[csrc->mc_top]) ? "leaf" : "branch",
+	    csrc->mc_ki[csrc->mc_top],
+		DKEY(&key),
+	    csrc->mc_pg[csrc->mc_top]->mp_pgno,
+	    cdst->mc_ki[cdst->mc_top], cdst->mc_pg[cdst->mc_top]->mp_pgno));
+
+	/* Add the node to the destination page.
+	 */
+	rc = mdb_node_add(cdst, cdst->mc_ki[cdst->mc_top], &key, &data, srcpg, flags);
+	if (rc != MDB_SUCCESS)
+		return rc;
+
+	/* Delete the node from the source page.
+	 */
+	mdb_node_del(csrc, key.mv_size);
+
+	{
+		/* Adjust other cursors pointing to mp */
+		MDB_cursor *m2, *m3;
+		MDB_dbi dbi = csrc->mc_dbi;
+		MDB_page *mp = csrc->mc_pg[csrc->mc_top];
+
+		for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
+			if (csrc->mc_flags & C_SUB)
+				m3 = &m2->mc_xcursor->mx_cursor;
+			else
+				m3 = m2;
+			if (m3 == csrc) continue;
+			if (m3->mc_pg[csrc->mc_top] == mp && m3->mc_ki[csrc->mc_top] ==
+				csrc->mc_ki[csrc->mc_top]) {
+				m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];
+				m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
+			}
+		}
+	}
+
+	/* Update the parent separators.
+	 */
+	if (csrc->mc_ki[csrc->mc_top] == 0) {
+		if (csrc->mc_ki[csrc->mc_top-1] != 0) {
+			if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
+				key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
+			} else {
+				srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
+				key.mv_size = NODEKSZ(srcnode);
+				key.mv_data = NODEKEY(srcnode);
+			}
+			DPRINTF(("update separator for source page %"Z"u to [%s]",
+				csrc->mc_pg[csrc->mc_top]->mp_pgno, DKEY(&key)));
+			mdb_cursor_copy(csrc, &mn);
+			mn.mc_snum--;
+			mn.mc_top--;
+			if ((rc = mdb_update_key(&mn, &key)) != MDB_SUCCESS)
+				return rc;
+		}
+		if (IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
+			MDB_val	 nullkey;
+			indx_t	ix = csrc->mc_ki[csrc->mc_top];
+			nullkey.mv_size = 0;
+			csrc->mc_ki[csrc->mc_top] = 0;
+			rc = mdb_update_key(csrc, &nullkey);
+			csrc->mc_ki[csrc->mc_top] = ix;
+			mdb_cassert(csrc, rc == MDB_SUCCESS);
+		}
+	}
+
+	if (cdst->mc_ki[cdst->mc_top] == 0) {
+		if (cdst->mc_ki[cdst->mc_top-1] != 0) {
+			if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
+				key.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, key.mv_size);
+			} else {
+				srcnode = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
+				key.mv_size = NODEKSZ(srcnode);
+				key.mv_data = NODEKEY(srcnode);
+			}
+			DPRINTF(("update separator for destination page %"Z"u to [%s]",
+				cdst->mc_pg[cdst->mc_top]->mp_pgno, DKEY(&key)));
+			mdb_cursor_copy(cdst, &mn);
+			mn.mc_snum--;
+			mn.mc_top--;
+			if ((rc = mdb_update_key(&mn, &key)) != MDB_SUCCESS)
+				return rc;
+		}
+		if (IS_BRANCH(cdst->mc_pg[cdst->mc_top])) {
+			MDB_val	 nullkey;
+			indx_t	ix = cdst->mc_ki[cdst->mc_top];
+			nullkey.mv_size = 0;
+			cdst->mc_ki[cdst->mc_top] = 0;
+			rc = mdb_update_key(cdst, &nullkey);
+			cdst->mc_ki[cdst->mc_top] = ix;
+			mdb_cassert(csrc, rc == MDB_SUCCESS);
+		}
+	}
+
+	return MDB_SUCCESS;
+}
+
+/** Merge one page into another.
+ *  The nodes from the page pointed to by \b csrc will
+ *	be copied to the page pointed to by \b cdst and then
+ *	the \b csrc page will be freed.
+ * @param[in] csrc Cursor pointing to the source page.
+ * @param[in] cdst Cursor pointing to the destination page.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst)
+{
+	MDB_page	*psrc, *pdst;
+	MDB_node	*srcnode;
+	MDB_val		 key, data;
+	unsigned	 nkeys;
+	int			 rc;
+	indx_t		 i, j;
+
+	psrc = csrc->mc_pg[csrc->mc_top];
+	pdst = cdst->mc_pg[cdst->mc_top];
+
+	DPRINTF(("merging page %"Z"u into %"Z"u", psrc->mp_pgno, pdst->mp_pgno));
+
+	mdb_cassert(csrc, csrc->mc_snum > 1);	/* can't merge root page */
+	mdb_cassert(csrc, cdst->mc_snum > 1);
+
+	/* Mark dst as dirty. */
+	if ((rc = mdb_page_touch(cdst)))
+		return rc;
+
+	/* Move all nodes from src to dst.
+	 */
+	j = nkeys = NUMKEYS(pdst);
+	if (IS_LEAF2(psrc)) {
+		key.mv_size = csrc->mc_db->md_pad;
+		key.mv_data = METADATA(psrc);
+		for (i = 0; i < NUMKEYS(psrc); i++, j++) {
+			rc = mdb_node_add(cdst, j, &key, NULL, 0, 0);
+			if (rc != MDB_SUCCESS)
+				return rc;
+			key.mv_data = (char *)key.mv_data + key.mv_size;
+		}
+	} else {
+		for (i = 0; i < NUMKEYS(psrc); i++, j++) {
+			srcnode = NODEPTR(psrc, i);
+			if (i == 0 && IS_BRANCH(psrc)) {
+				MDB_cursor mn;
+				MDB_node *s2;
+				mdb_cursor_copy(csrc, &mn);
+				/* must find the lowest key below src */
+				rc = mdb_page_search_lowest(&mn);
+				if (rc)
+					return rc;
+				if (IS_LEAF2(mn.mc_pg[mn.mc_top])) {
+					key.mv_size = mn.mc_db->md_pad;
+					key.mv_data = LEAF2KEY(mn.mc_pg[mn.mc_top], 0, key.mv_size);
+				} else {
+					s2 = NODEPTR(mn.mc_pg[mn.mc_top], 0);
+					key.mv_size = NODEKSZ(s2);
+					key.mv_data = NODEKEY(s2);
+				}
+			} else {
+				key.mv_size = srcnode->mn_ksize;
+				key.mv_data = NODEKEY(srcnode);
+			}
+
+			data.mv_size = NODEDSZ(srcnode);
+			data.mv_data = NODEDATA(srcnode);
+			rc = mdb_node_add(cdst, j, &key, &data, NODEPGNO(srcnode), srcnode->mn_flags);
+			if (rc != MDB_SUCCESS)
+				return rc;
+		}
+	}
+
+	DPRINTF(("dst page %"Z"u now has %u keys (%.1f%% filled)",
+	    pdst->mp_pgno, NUMKEYS(pdst),
+		(float)PAGEFILL(cdst->mc_txn->mt_env, pdst) / 10));
+
+	/* Unlink the src page from parent and add to free list.
+	 */
+	csrc->mc_top--;
+	mdb_node_del(csrc, 0);
+	if (csrc->mc_ki[csrc->mc_top] == 0) {
+		key.mv_size = 0;
+		rc = mdb_update_key(csrc, &key);
+		if (rc) {
+			csrc->mc_top++;
+			return rc;
+		}
+	}
+	csrc->mc_top++;
+
+	psrc = csrc->mc_pg[csrc->mc_top];
+	/* If not operating on FreeDB, allow this page to be reused
+	 * in this txn. Otherwise just add to free list.
+	 */
+	rc = mdb_page_loose(csrc, psrc);
+	if (rc)
+		return rc;
+	if (IS_LEAF(psrc))
+		csrc->mc_db->md_leaf_pages--;
+	else
+		csrc->mc_db->md_branch_pages--;
+	{
+		/* Adjust other cursors pointing to mp */
+		MDB_cursor *m2, *m3;
+		MDB_dbi dbi = csrc->mc_dbi;
+
+		for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
+			if (csrc->mc_flags & C_SUB)
+				m3 = &m2->mc_xcursor->mx_cursor;
+			else
+				m3 = m2;
+			if (m3 == csrc) continue;
+			if (m3->mc_snum < csrc->mc_snum) continue;
+			if (m3->mc_pg[csrc->mc_top] == psrc) {
+				m3->mc_pg[csrc->mc_top] = pdst;
+				m3->mc_ki[csrc->mc_top] += nkeys;
+			}
+		}
+	}
+	{
+		unsigned int snum = cdst->mc_snum;
+		uint16_t depth = cdst->mc_db->md_depth;
+		mdb_cursor_pop(cdst);
+		rc = mdb_rebalance(cdst);
+		/* Did the tree shrink? */
+		if (depth > cdst->mc_db->md_depth)
+			snum--;
+		cdst->mc_snum = snum;
+		cdst->mc_top = snum-1;
+	}
+	return rc;
+}
+
+/** Copy the contents of a cursor.
+ * @param[in] csrc The cursor to copy from.
+ * @param[out] cdst The cursor to copy to.
+ */
+static void
+mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst)
+{
+	unsigned int i;
+
+	cdst->mc_txn = csrc->mc_txn;
+	cdst->mc_dbi = csrc->mc_dbi;
+	cdst->mc_db  = csrc->mc_db;
+	cdst->mc_dbx = csrc->mc_dbx;
+	cdst->mc_snum = csrc->mc_snum;
+	cdst->mc_top = csrc->mc_top;
+	cdst->mc_flags = csrc->mc_flags;
+
+	for (i=0; i<csrc->mc_snum; i++) {
+		cdst->mc_pg[i] = csrc->mc_pg[i];
+		cdst->mc_ki[i] = csrc->mc_ki[i];
+	}
+}
+
+/** Rebalance the tree after a delete operation.
+ * @param[in] mc Cursor pointing to the page where rebalancing
+ * should begin.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_rebalance(MDB_cursor *mc)
+{
+	MDB_node	*node;
+	int rc;
+	unsigned int ptop, minkeys;
+	MDB_cursor	mn;
+	indx_t oldki;
+
+	minkeys = 1 + (IS_BRANCH(mc->mc_pg[mc->mc_top]));
+	DPRINTF(("rebalancing %s page %"Z"u (has %u keys, %.1f%% full)",
+	    IS_LEAF(mc->mc_pg[mc->mc_top]) ? "leaf" : "branch",
+	    mdb_dbg_pgno(mc->mc_pg[mc->mc_top]), NUMKEYS(mc->mc_pg[mc->mc_top]),
+		(float)PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) / 10));
+
+	if (PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) >= FILL_THRESHOLD &&
+		NUMKEYS(mc->mc_pg[mc->mc_top]) >= minkeys) {
+		DPRINTF(("no need to rebalance page %"Z"u, above fill threshold",
+		    mdb_dbg_pgno(mc->mc_pg[mc->mc_top])));
+		return MDB_SUCCESS;
+	}
+
+	if (mc->mc_snum < 2) {
+		MDB_page *mp = mc->mc_pg[0];
+		if (IS_SUBP(mp)) {
+			DPUTS("Can't rebalance a subpage, ignoring");
+			return MDB_SUCCESS;
+		}
+		if (NUMKEYS(mp) == 0) {
+			DPUTS("tree is completely empty");
+			mc->mc_db->md_root = P_INVALID;
+			mc->mc_db->md_depth = 0;
+			mc->mc_db->md_leaf_pages = 0;
+			rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
+			if (rc)
+				return rc;
+			/* Adjust cursors pointing to mp */
+			mc->mc_snum = 0;
+			mc->mc_top = 0;
+			mc->mc_flags &= ~C_INITIALIZED;
+			{
+				MDB_cursor *m2, *m3;
+				MDB_dbi dbi = mc->mc_dbi;
+
+				for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
+					if (mc->mc_flags & C_SUB)
+						m3 = &m2->mc_xcursor->mx_cursor;
+					else
+						m3 = m2;
+					if (m3->mc_snum < mc->mc_snum) continue;
+					if (m3->mc_pg[0] == mp) {
+						m3->mc_snum = 0;
+						m3->mc_top = 0;
+						m3->mc_flags &= ~C_INITIALIZED;
+					}
+				}
+			}
+		} else if (IS_BRANCH(mp) && NUMKEYS(mp) == 1) {
+			int i;
+			DPUTS("collapsing root page!");
+			rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
+			if (rc)
+				return rc;
+			mc->mc_db->md_root = NODEPGNO(NODEPTR(mp, 0));
+			rc = mdb_page_get(mc->mc_txn,mc->mc_db->md_root,&mc->mc_pg[0],NULL);
+			if (rc)
+				return rc;
+			mc->mc_db->md_depth--;
+			mc->mc_db->md_branch_pages--;
+			mc->mc_ki[0] = mc->mc_ki[1];
+			for (i = 1; i<mc->mc_db->md_depth; i++) {
+				mc->mc_pg[i] = mc->mc_pg[i+1];
+				mc->mc_ki[i] = mc->mc_ki[i+1];
+			}
+			{
+				/* Adjust other cursors pointing to mp */
+				MDB_cursor *m2, *m3;
+				MDB_dbi dbi = mc->mc_dbi;
+
+				for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
+					if (mc->mc_flags & C_SUB)
+						m3 = &m2->mc_xcursor->mx_cursor;
+					else
+						m3 = m2;
+					if (m3 == mc || m3->mc_snum < mc->mc_snum) continue;
+					if (m3->mc_pg[0] == mp) {
+						m3->mc_snum--;
+						m3->mc_top--;
+						for (i=0; i<m3->mc_snum; i++) {
+							m3->mc_pg[i] = m3->mc_pg[i+1];
+							m3->mc_ki[i] = m3->mc_ki[i+1];
+						}
+					}
+				}
+			}
+		} else
+			DPUTS("root page doesn't need rebalancing");
+		return MDB_SUCCESS;
+	}
+
+	/* The parent (branch page) must have at least 2 pointers,
+	 * otherwise the tree is invalid.
+	 */
+	ptop = mc->mc_top-1;
+	mdb_cassert(mc, NUMKEYS(mc->mc_pg[ptop]) > 1);
+
+	/* Leaf page fill factor is below the threshold.
+	 * Try to move keys from left or right neighbor, or
+	 * merge with a neighbor page.
+	 */
+
+	/* Find neighbors.
+	 */
+	mdb_cursor_copy(mc, &mn);
+	mn.mc_xcursor = NULL;
+
+	oldki = mc->mc_ki[mc->mc_top];
+	if (mc->mc_ki[ptop] == 0) {
+		/* We're the leftmost leaf in our parent.
+		 */
+		DPUTS("reading right neighbor");
+		mn.mc_ki[ptop]++;
+		node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
+		rc = mdb_page_get(mc->mc_txn,NODEPGNO(node),&mn.mc_pg[mn.mc_top],NULL);
+		if (rc)
+			return rc;
+		mn.mc_ki[mn.mc_top] = 0;
+		mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
+	} else {
+		/* There is at least one neighbor to the left.
+		 */
+		DPUTS("reading left neighbor");
+		mn.mc_ki[ptop]--;
+		node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
+		rc = mdb_page_get(mc->mc_txn,NODEPGNO(node),&mn.mc_pg[mn.mc_top],NULL);
+		if (rc)
+			return rc;
+		mn.mc_ki[mn.mc_top] = NUMKEYS(mn.mc_pg[mn.mc_top]) - 1;
+		mc->mc_ki[mc->mc_top] = 0;
+	}
+
+	DPRINTF(("found neighbor page %"Z"u (%u keys, %.1f%% full)",
+	    mn.mc_pg[mn.mc_top]->mp_pgno, NUMKEYS(mn.mc_pg[mn.mc_top]),
+		(float)PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) / 10));
+
+	/* If the neighbor page is above threshold and has enough keys,
+	 * move one key from it. Otherwise we should try to merge them.
+	 * (A branch page must never have less than 2 keys.)
+	 */
+	minkeys = 1 + (IS_BRANCH(mn.mc_pg[mn.mc_top]));
+	if (PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) >= FILL_THRESHOLD && NUMKEYS(mn.mc_pg[mn.mc_top]) > minkeys) {
+		rc = mdb_node_move(&mn, mc);
+		if (mc->mc_ki[ptop]) {
+			oldki++;
+		}
+	} else {
+		if (mc->mc_ki[ptop] == 0) {
+			rc = mdb_page_merge(&mn, mc);
+		} else {
+			oldki += NUMKEYS(mn.mc_pg[mn.mc_top]);
+			mn.mc_ki[mn.mc_top] += mc->mc_ki[mn.mc_top] + 1;
+			rc = mdb_page_merge(mc, &mn);
+			mdb_cursor_copy(&mn, mc);
+		}
+		mc->mc_flags &= ~C_EOF;
+	}
+	mc->mc_ki[mc->mc_top] = oldki;
+	return rc;
+}
+
+/** Complete a delete operation started by #mdb_cursor_del(). */
+static int
+mdb_cursor_del0(MDB_cursor *mc)
+{
+	int rc;
+	MDB_page *mp;
+	indx_t ki;
+	unsigned int nkeys;
+
+	ki = mc->mc_ki[mc->mc_top];
+	mdb_node_del(mc, mc->mc_db->md_pad);
+	mc->mc_db->md_entries--;
+	rc = mdb_rebalance(mc);
+
+	if (rc == MDB_SUCCESS) {
+		MDB_cursor *m2, *m3;
+		MDB_dbi dbi = mc->mc_dbi;
+
+		mp = mc->mc_pg[mc->mc_top];
+		nkeys = NUMKEYS(mp);
+
+		/* if mc points past last node in page, find next sibling */
+		if (mc->mc_ki[mc->mc_top] >= nkeys) {
+			rc = mdb_cursor_sibling(mc, 1);
+			if (rc == MDB_NOTFOUND) {
+				mc->mc_flags |= C_EOF;
+				rc = MDB_SUCCESS;
+			}
+		}
+
+		/* Adjust other cursors pointing to mp */
+		for (m2 = mc->mc_txn->mt_cursors[dbi]; !rc && m2; m2=m2->mc_next) {
+			m3 = (mc->mc_flags & C_SUB) ? &m2->mc_xcursor->mx_cursor : m2;
+			if (! (m2->mc_flags & m3->mc_flags & C_INITIALIZED))
+				continue;
+			if (m3 == mc || m3->mc_snum < mc->mc_snum)
+				continue;
+			if (m3->mc_pg[mc->mc_top] == mp) {
+				if (m3->mc_ki[mc->mc_top] >= ki) {
+					m3->mc_flags |= C_DEL;
+					if (m3->mc_ki[mc->mc_top] > ki)
+						m3->mc_ki[mc->mc_top]--;
+					else if (mc->mc_db->md_flags & MDB_DUPSORT)
+						m3->mc_xcursor->mx_cursor.mc_flags |= C_EOF;
+				}
+				if (m3->mc_ki[mc->mc_top] >= nkeys) {
+					rc = mdb_cursor_sibling(m3, 1);
+					if (rc == MDB_NOTFOUND) {
+						m3->mc_flags |= C_EOF;
+						rc = MDB_SUCCESS;
+					}
+				}
+			}
+		}
+		mc->mc_flags |= C_DEL;
+	}
+
+	if (rc)
+		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
+	return rc;
+}
+
+int
+mdb_del(MDB_txn *txn, MDB_dbi dbi,
+    MDB_val *key, MDB_val *data)
+{
+	if (!key || dbi == FREE_DBI || !TXN_DBI_EXIST(txn, dbi))
+		return EINVAL;
+
+	if (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_ERROR))
+		return (txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
+
+	if (!F_ISSET(txn->mt_dbs[dbi].md_flags, MDB_DUPSORT)) {
+		/* must ignore any data */
+		data = NULL;
+	}
+
+	return mdb_del0(txn, dbi, key, data, 0);
+}
+
+static int
+mdb_del0(MDB_txn *txn, MDB_dbi dbi,
+	MDB_val *key, MDB_val *data, unsigned flags)
+{
+	MDB_cursor mc;
+	MDB_xcursor mx;
+	MDB_cursor_op op;
+	MDB_val rdata, *xdata;
+	int		 rc, exact = 0;
+	DKBUF;
+
+	DPRINTF(("====> delete db %u key [%s]", dbi, DKEY(key)));
+
+	mdb_cursor_init(&mc, txn, dbi, &mx);
+
+	if (data) {
+		op = MDB_GET_BOTH;
+		rdata = *data;
+		xdata = &rdata;
+	} else {
+		op = MDB_SET;
+		xdata = NULL;
+		flags |= MDB_NODUPDATA;
+	}
+	rc = mdb_cursor_set(&mc, key, xdata, op, &exact);
+	if (rc == 0) {
+		/* let mdb_page_split know about this cursor if needed:
+		 * delete will trigger a rebalance; if it needs to move
+		 * a node from one page to another, it will have to
+		 * update the parent's separator key(s). If the new sepkey
+		 * is larger than the current one, the parent page may
+		 * run out of space, triggering a split. We need this
+		 * cursor to be consistent until the end of the rebalance.
+		 */
+		mc.mc_flags |= C_UNTRACK;
+		mc.mc_next = txn->mt_cursors[dbi];
+		txn->mt_cursors[dbi] = &mc;
+		rc = mdb_cursor_del(&mc, flags);
+		txn->mt_cursors[dbi] = mc.mc_next;
+	}
+	return rc;
+}
+
+/** Split a page and insert a new node.
+ * @param[in,out] mc Cursor pointing to the page and desired insertion index.
+ * The cursor will be updated to point to the actual page and index where
+ * the node got inserted after the split.
+ * @param[in] newkey The key for the newly inserted node.
+ * @param[in] newdata The data for the newly inserted node.
+ * @param[in] newpgno The page number, if the new node is a branch node.
+ * @param[in] nflags The #NODE_ADD_FLAGS for the new node.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno,
+	unsigned int nflags)
+{
+	unsigned int flags;
+	int		 rc = MDB_SUCCESS, new_root = 0, did_split = 0;
+	indx_t		 newindx;
+	pgno_t		 pgno = 0;
+	int	 i, j, split_indx, nkeys, pmax;
+	MDB_env 	*env = mc->mc_txn->mt_env;
+	MDB_node	*node;
+	MDB_val	 sepkey, rkey, xdata, *rdata = &xdata;
+	MDB_page	*copy = NULL;
+	MDB_page	*mp, *rp, *pp;
+	int ptop;
+	MDB_cursor	mn;
+	DKBUF;
+
+	mp = mc->mc_pg[mc->mc_top];
+	newindx = mc->mc_ki[mc->mc_top];
+	nkeys = NUMKEYS(mp);
+
+	DPRINTF(("-----> splitting %s page %"Z"u and adding [%s] at index %i/%i",
+	    IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno,
+	    DKEY(newkey), mc->mc_ki[mc->mc_top], nkeys));
+
+	/* Create a right sibling. */
+	if ((rc = mdb_page_new(mc, mp->mp_flags, 1, &rp)))
+		return rc;
+	DPRINTF(("new right sibling: page %"Z"u", rp->mp_pgno));
+
+	if (mc->mc_snum < 2) {
+		if ((rc = mdb_page_new(mc, P_BRANCH, 1, &pp)))
+			goto done;
+		/* shift current top to make room for new parent */
+		mc->mc_pg[1] = mc->mc_pg[0];
+		mc->mc_ki[1] = mc->mc_ki[0];
+		mc->mc_pg[0] = pp;
+		mc->mc_ki[0] = 0;
+		mc->mc_db->md_root = pp->mp_pgno;
+		DPRINTF(("root split! new root = %"Z"u", pp->mp_pgno));
+		mc->mc_db->md_depth++;
+		new_root = 1;
+
+		/* Add left (implicit) pointer. */
+		if ((rc = mdb_node_add(mc, 0, NULL, NULL, mp->mp_pgno, 0)) != MDB_SUCCESS) {
+			/* undo the pre-push */
+			mc->mc_pg[0] = mc->mc_pg[1];
+			mc->mc_ki[0] = mc->mc_ki[1];
+			mc->mc_db->md_root = mp->mp_pgno;
+			mc->mc_db->md_depth--;
+			goto done;
+		}
+		mc->mc_snum = 2;
+		mc->mc_top = 1;
+		ptop = 0;
+	} else {
+		ptop = mc->mc_top-1;
+		DPRINTF(("parent branch page is %"Z"u", mc->mc_pg[ptop]->mp_pgno));
+	}
+
+	mc->mc_flags |= C_SPLITTING;
+	mdb_cursor_copy(mc, &mn);
+	mn.mc_pg[mn.mc_top] = rp;
+	mn.mc_ki[ptop] = mc->mc_ki[ptop]+1;
+
+	if (nflags & MDB_APPEND) {
+		mn.mc_ki[mn.mc_top] = 0;
+		sepkey = *newkey;
+		split_indx = newindx;
+		nkeys = 0;
+	} else {
+
+		split_indx = (nkeys+1) / 2;
+
+		if (IS_LEAF2(rp)) {
+			char *split, *ins;
+			int x;
+			unsigned int lsize, rsize, ksize;
+			/* Move half of the keys to the right sibling */
+			x = mc->mc_ki[mc->mc_top] - split_indx;
+			ksize = mc->mc_db->md_pad;
+			split = LEAF2KEY(mp, split_indx, ksize);
+			rsize = (nkeys - split_indx) * ksize;
+			lsize = (nkeys - split_indx) * sizeof(indx_t);
+			mp->mp_lower -= lsize;
+			rp->mp_lower += lsize;
+			mp->mp_upper += rsize - lsize;
+			rp->mp_upper -= rsize - lsize;
+			sepkey.mv_size = ksize;
+			if (newindx == split_indx) {
+				sepkey.mv_data = newkey->mv_data;
+			} else {
+				sepkey.mv_data = split;
+			}
+			if (x<0) {
+				ins = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], ksize);
+				memcpy(rp->mp_ptrs, split, rsize);
+				sepkey.mv_data = rp->mp_ptrs;
+				memmove(ins+ksize, ins, (split_indx - mc->mc_ki[mc->mc_top]) * ksize);
+				memcpy(ins, newkey->mv_data, ksize);
+				mp->mp_lower += sizeof(indx_t);
+				mp->mp_upper -= ksize - sizeof(indx_t);
+			} else {
+				if (x)
+					memcpy(rp->mp_ptrs, split, x * ksize);
+				ins = LEAF2KEY(rp, x, ksize);
+				memcpy(ins, newkey->mv_data, ksize);
+				memcpy(ins+ksize, split + x * ksize, rsize - x * ksize);
+				rp->mp_lower += sizeof(indx_t);
+				rp->mp_upper -= ksize - sizeof(indx_t);
+				mc->mc_ki[mc->mc_top] = x;
+				mc->mc_pg[mc->mc_top] = rp;
+			}
+		} else {
+			int psize, nsize, k;
+			/* Maximum free space in an empty page */
+			pmax = env->me_psize - PAGEHDRSZ;
+			if (IS_LEAF(mp))
+				nsize = mdb_leaf_size(env, newkey, newdata);
+			else
+				nsize = mdb_branch_size(env, newkey);
+			nsize = EVEN(nsize);
+
+			/* grab a page to hold a temporary copy */
+			copy = mdb_page_malloc(mc->mc_txn, 1);
+			if (copy == NULL) {
+				rc = ENOMEM;
+				goto done;
+			}
+			copy->mp_pgno  = mp->mp_pgno;
+			copy->mp_flags = mp->mp_flags;
+			copy->mp_lower = (PAGEHDRSZ-PAGEBASE);
+			copy->mp_upper = env->me_psize - PAGEBASE;
+
+			/* prepare to insert */
+			for (i=0, j=0; i<nkeys; i++) {
+				if (i == newindx) {
+					copy->mp_ptrs[j++] = 0;
+				}
+				copy->mp_ptrs[j++] = mp->mp_ptrs[i];
+			}
+
+			/* When items are relatively large the split point needs
+			 * to be checked, because being off-by-one will make the
+			 * difference between success or failure in mdb_node_add.
+			 *
+			 * It's also relevant if a page happens to be laid out
+			 * such that one half of its nodes are all "small" and
+			 * the other half of its nodes are "large." If the new
+			 * item is also "large" and falls on the half with
+			 * "large" nodes, it also may not fit.
+			 *
+			 * As a final tweak, if the new item goes on the last
+			 * spot on the page (and thus, onto the new page), bias
+			 * the split so the new page is emptier than the old page.
+			 * This yields better packing during sequential inserts.
+			 */
+			if (nkeys < 20 || nsize > pmax/16 || newindx >= nkeys) {
+				/* Find split point */
+				psize = 0;
+				if (newindx <= split_indx || newindx >= nkeys) {
+					i = 0; j = 1;
+					k = newindx >= nkeys ? nkeys : split_indx+2;
+				} else {
+					i = nkeys; j = -1;
+					k = split_indx-1;
+				}
+				for (; i!=k; i+=j) {
+					if (i == newindx) {
+						psize += nsize;
+						node = NULL;
+					} else {
+						node = (MDB_node *)((char *)mp + copy->mp_ptrs[i] + PAGEBASE);
+						psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
+						if (IS_LEAF(mp)) {
+							if (F_ISSET(node->mn_flags, F_BIGDATA))
+								psize += sizeof(pgno_t);
+							else
+								psize += NODEDSZ(node);
+						}
+						psize = EVEN(psize);
+					}
+					if (psize > pmax || i == k-j) {
+						split_indx = i + (j<0);
+						break;
+					}
+				}
+			}
+			if (split_indx == newindx) {
+				sepkey.mv_size = newkey->mv_size;
+				sepkey.mv_data = newkey->mv_data;
+			} else {
+				node = (MDB_node *)((char *)mp + copy->mp_ptrs[split_indx] + PAGEBASE);
+				sepkey.mv_size = node->mn_ksize;
+				sepkey.mv_data = NODEKEY(node);
+			}
+		}
+	}
+
+	DPRINTF(("separator is %d [%s]", split_indx, DKEY(&sepkey)));
+
+	/* Copy separator key to the parent.
+	 */
+	if (SIZELEFT(mn.mc_pg[ptop]) < mdb_branch_size(env, &sepkey)) {
+		mn.mc_snum--;
+		mn.mc_top--;
+		did_split = 1;
+		rc = mdb_page_split(&mn, &sepkey, NULL, rp->mp_pgno, 0);
+		if (rc)
+			goto done;
+
+		/* root split? */
+		if (mn.mc_snum == mc->mc_snum) {
+			mc->mc_pg[mc->mc_snum] = mc->mc_pg[mc->mc_top];
+			mc->mc_ki[mc->mc_snum] = mc->mc_ki[mc->mc_top];
+			mc->mc_pg[mc->mc_top] = mc->mc_pg[ptop];
+			mc->mc_ki[mc->mc_top] = mc->mc_ki[ptop];
+			mc->mc_snum++;
+			mc->mc_top++;
+			ptop++;
+		}
+		/* Right page might now have changed parent.
+		 * Check if left page also changed parent.
+		 */
+		if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
+		    mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
+			for (i=0; i<ptop; i++) {
+				mc->mc_pg[i] = mn.mc_pg[i];
+				mc->mc_ki[i] = mn.mc_ki[i];
+			}
+			mc->mc_pg[ptop] = mn.mc_pg[ptop];
+			if (mn.mc_ki[ptop]) {
+				mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;
+			} else {
+				/* find right page's left sibling */
+				mc->mc_ki[ptop] = mn.mc_ki[ptop];
+				mdb_cursor_sibling(mc, 0);
+			}
+		}
+	} else {
+		mn.mc_top--;
+		rc = mdb_node_add(&mn, mn.mc_ki[ptop], &sepkey, NULL, rp->mp_pgno, 0);
+		mn.mc_top++;
+	}
+	mc->mc_flags ^= C_SPLITTING;
+	if (rc != MDB_SUCCESS) {
+		goto done;
+	}
+	if (nflags & MDB_APPEND) {
+		mc->mc_pg[mc->mc_top] = rp;
+		mc->mc_ki[mc->mc_top] = 0;
+		rc = mdb_node_add(mc, 0, newkey, newdata, newpgno, nflags);
+		if (rc)
+			goto done;
+		for (i=0; i<mc->mc_top; i++)
+			mc->mc_ki[i] = mn.mc_ki[i];
+	} else if (!IS_LEAF2(mp)) {
+		/* Move nodes */
+		mc->mc_pg[mc->mc_top] = rp;
+		i = split_indx;
+		j = 0;
+		do {
+			if (i == newindx) {
+				rkey.mv_data = newkey->mv_data;
+				rkey.mv_size = newkey->mv_size;
+				if (IS_LEAF(mp)) {
+					rdata = newdata;
+				} else
+					pgno = newpgno;
+				flags = nflags;
+				/* Update index for the new key. */
+				mc->mc_ki[mc->mc_top] = j;
+			} else {
+				node = (MDB_node *)((char *)mp + copy->mp_ptrs[i] + PAGEBASE);
+				rkey.mv_data = NODEKEY(node);
+				rkey.mv_size = node->mn_ksize;
+				if (IS_LEAF(mp)) {
+					xdata.mv_data = NODEDATA(node);
+					xdata.mv_size = NODEDSZ(node);
+					rdata = &xdata;
+				} else
+					pgno = NODEPGNO(node);
+				flags = node->mn_flags;
+			}
+
+			if (!IS_LEAF(mp) && j == 0) {
+				/* First branch index doesn't need key data. */
+				rkey.mv_size = 0;
+			}
+
+			rc = mdb_node_add(mc, j, &rkey, rdata, pgno, flags);
+			if (rc)
+				goto done;
+			if (i == nkeys) {
+				i = 0;
+				j = 0;
+				mc->mc_pg[mc->mc_top] = copy;
+			} else {
+				i++;
+				j++;
+			}
+		} while (i != split_indx);
+
+		nkeys = NUMKEYS(copy);
+		for (i=0; i<nkeys; i++)
+			mp->mp_ptrs[i] = copy->mp_ptrs[i];
+		mp->mp_lower = copy->mp_lower;
+		mp->mp_upper = copy->mp_upper;
+		memcpy(NODEPTR(mp, nkeys-1), NODEPTR(copy, nkeys-1),
+			env->me_psize - copy->mp_upper - PAGEBASE);
+
+		/* reset back to original page */
+		if (newindx < split_indx) {
+			mc->mc_pg[mc->mc_top] = mp;
+			if (nflags & MDB_RESERVE) {
+				node = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
+				if (!(node->mn_flags & F_BIGDATA))
+					newdata->mv_data = NODEDATA(node);
+			}
+		} else {
+			mc->mc_pg[mc->mc_top] = rp;
+			mc->mc_ki[ptop]++;
+			/* Make sure mc_ki is still valid.
+			 */
+			if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
+				mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
+				for (i=0; i<=ptop; i++) {
+					mc->mc_pg[i] = mn.mc_pg[i];
+					mc->mc_ki[i] = mn.mc_ki[i];
+				}
+			}
+		}
+	}
+
+	{
+		/* Adjust other cursors pointing to mp */
+		MDB_cursor *m2, *m3;
+		MDB_dbi dbi = mc->mc_dbi;
+		int fixup = NUMKEYS(mp);
+
+		for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
+			if (mc->mc_flags & C_SUB)
+				m3 = &m2->mc_xcursor->mx_cursor;
+			else
+				m3 = m2;
+			if (m3 == mc)
+				continue;
+			if (!(m2->mc_flags & m3->mc_flags & C_INITIALIZED))
+				continue;
+			if (m3->mc_flags & C_SPLITTING)
+				continue;
+			if (new_root) {
+				int k;
+				/* root split */
+				for (k=m3->mc_top; k>=0; k--) {
+					m3->mc_ki[k+1] = m3->mc_ki[k];
+					m3->mc_pg[k+1] = m3->mc_pg[k];
+				}
+				if (m3->mc_ki[0] >= split_indx) {
+					m3->mc_ki[0] = 1;
+				} else {
+					m3->mc_ki[0] = 0;
+				}
+				m3->mc_pg[0] = mc->mc_pg[0];
+				m3->mc_snum++;
+				m3->mc_top++;
+			}
+			if (m3->mc_top >= mc->mc_top && m3->mc_pg[mc->mc_top] == mp) {
+				if (m3->mc_ki[mc->mc_top] >= newindx && !(nflags & MDB_SPLIT_REPLACE))
+					m3->mc_ki[mc->mc_top]++;
+				if (m3->mc_ki[mc->mc_top] >= fixup) {
+					m3->mc_pg[mc->mc_top] = rp;
+					m3->mc_ki[mc->mc_top] -= fixup;
+					m3->mc_ki[ptop] = mn.mc_ki[ptop];
+				}
+			} else if (!did_split && m3->mc_top >= ptop && m3->mc_pg[ptop] == mc->mc_pg[ptop] &&
+				m3->mc_ki[ptop] >= mc->mc_ki[ptop]) {
+				m3->mc_ki[ptop]++;
+			}
+		}
+	}
+	DPRINTF(("mp left: %d, rp left: %d", SIZELEFT(mp), SIZELEFT(rp)));
+
+done:
+	if (copy)					/* tmp page */
+		mdb_page_free(env, copy);
+	if (rc)
+		mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
+	return rc;
+}
+
+int
+mdb_put(MDB_txn *txn, MDB_dbi dbi,
+    MDB_val *key, MDB_val *data, unsigned int flags)
+{
+	MDB_cursor mc;
+	MDB_xcursor mx;
+
+	if (!key || !data || dbi == FREE_DBI || !TXN_DBI_EXIST(txn, dbi))
+		return EINVAL;
+
+	if ((flags & (MDB_NOOVERWRITE|MDB_NODUPDATA|MDB_RESERVE|MDB_APPEND|MDB_APPENDDUP)) != flags)
+		return EINVAL;
+
+	mdb_cursor_init(&mc, txn, dbi, &mx);
+	return mdb_cursor_put(&mc, key, data, flags);
+}
+
+#ifndef MDB_WBUF
+#define MDB_WBUF	(1024*1024)
+#endif
+
+	/** State needed for a compacting copy. */
+typedef struct mdb_copy {
+	pthread_mutex_t mc_mutex;
+	pthread_cond_t mc_cond;
+	char *mc_wbuf[2];
+	char *mc_over[2];
+	MDB_env *mc_env;
+	MDB_txn *mc_txn;
+	int mc_wlen[2];
+	int mc_olen[2];
+	pgno_t mc_next_pgno;
+	HANDLE mc_fd;
+	int mc_status;
+	volatile int mc_new;
+	int mc_toggle;
+
+} mdb_copy;
+
+	/** Dedicated writer thread for compacting copy. */
+static THREAD_RET ESECT
+mdb_env_copythr(void *arg)
+{
+	mdb_copy *my = arg;
+	char *ptr;
+	int toggle = 0, wsize, rc;
+#ifdef _WIN32
+	DWORD len;
+#define DO_WRITE(rc, fd, ptr, w2, len)	rc = WriteFile(fd, ptr, w2, &len, NULL)
+#else
+	int len;
+#define DO_WRITE(rc, fd, ptr, w2, len)	len = write(fd, ptr, w2); rc = (len >= 0)
+#endif
+
+	pthread_mutex_lock(&my->mc_mutex);
+	my->mc_new = 0;
+	pthread_cond_signal(&my->mc_cond);
+	for(;;) {
+		while (!my->mc_new)
+			pthread_cond_wait(&my->mc_cond, &my->mc_mutex);
+		if (my->mc_new < 0) {
+			my->mc_new = 0;
+			break;
+		}
+		my->mc_new = 0;
+		wsize = my->mc_wlen[toggle];
+		ptr = my->mc_wbuf[toggle];
+again:
+		while (wsize > 0) {
+			DO_WRITE(rc, my->mc_fd, ptr, wsize, len);
+			if (!rc) {
+				rc = ErrCode();
+				break;
+			} else if (len > 0) {
+				rc = MDB_SUCCESS;
+				ptr += len;
+				wsize -= len;
+				continue;
+			} else {
+				rc = EIO;
+				break;
+			}
+		}
+		if (rc) {
+			my->mc_status = rc;
+			break;
+		}
+		/* If there's an overflow page tail, write it too */
+		if (my->mc_olen[toggle]) {
+			wsize = my->mc_olen[toggle];
+			ptr = my->mc_over[toggle];
+			my->mc_olen[toggle] = 0;
+			goto again;
+		}
+		my->mc_wlen[toggle] = 0;
+		toggle ^= 1;
+		pthread_cond_signal(&my->mc_cond);
+	}
+	pthread_cond_signal(&my->mc_cond);
+	pthread_mutex_unlock(&my->mc_mutex);
+	return (THREAD_RET)0;
+#undef DO_WRITE
+}
+
+	/** Tell the writer thread there's a buffer ready to write */
+static int ESECT
+mdb_env_cthr_toggle(mdb_copy *my, int st)
+{
+	int toggle = my->mc_toggle ^ 1;
+	pthread_mutex_lock(&my->mc_mutex);
+	if (my->mc_status) {
+		pthread_mutex_unlock(&my->mc_mutex);
+		return my->mc_status;
+	}
+	while (my->mc_new == 1)
+		pthread_cond_wait(&my->mc_cond, &my->mc_mutex);
+	my->mc_new = st;
+	my->mc_toggle = toggle;
+	pthread_cond_signal(&my->mc_cond);
+	pthread_mutex_unlock(&my->mc_mutex);
+	return 0;
+}
+
+	/** Depth-first tree traversal for compacting copy. */
+static int ESECT
+mdb_env_cwalk(mdb_copy *my, pgno_t *pg, int flags)
+{
+	MDB_cursor mc;
+	MDB_txn *txn = my->mc_txn;
+	MDB_node *ni;
+	MDB_page *mo, *mp, *leaf;
+	char *buf, *ptr;
+	int rc, toggle;
+	unsigned int i;
+
+	/* Empty DB, nothing to do */
+	if (*pg == P_INVALID)
+		return MDB_SUCCESS;
+
+	mc.mc_snum = 1;
+	mc.mc_top = 0;
+	mc.mc_txn = txn;
+
+	rc = mdb_page_get(my->mc_txn, *pg, &mc.mc_pg[0], NULL);
+	if (rc)
+		return rc;
+	rc = mdb_page_search_root(&mc, NULL, MDB_PS_FIRST);
+	if (rc)
+		return rc;
+
+	/* Make cursor pages writable */
+	buf = ptr = malloc(my->mc_env->me_psize * mc.mc_snum);
+	if (buf == NULL)
+		return ENOMEM;
+
+	for (i=0; i<mc.mc_top; i++) {
+		mdb_page_copy((MDB_page *)ptr, mc.mc_pg[i], my->mc_env->me_psize);
+		mc.mc_pg[i] = (MDB_page *)ptr;
+		ptr += my->mc_env->me_psize;
+	}
+
+	/* This is writable space for a leaf page. Usually not needed. */
+	leaf = (MDB_page *)ptr;
+
+	toggle = my->mc_toggle;
+	while (mc.mc_snum > 0) {
+		unsigned n;
+		mp = mc.mc_pg[mc.mc_top];
+		n = NUMKEYS(mp);
+
+		if (IS_LEAF(mp)) {
+			if (!IS_LEAF2(mp) && !(flags & F_DUPDATA)) {
+				for (i=0; i<n; i++) {
+					ni = NODEPTR(mp, i);
+					if (ni->mn_flags & F_BIGDATA) {
+						MDB_page *omp;
+						pgno_t pg;
+
+						/* Need writable leaf */
+						if (mp != leaf) {
+							mc.mc_pg[mc.mc_top] = leaf;
+							mdb_page_copy(leaf, mp, my->mc_env->me_psize);
+							mp = leaf;
+							ni = NODEPTR(mp, i);
+						}
+
+						memcpy(&pg, NODEDATA(ni), sizeof(pg));
+						rc = mdb_page_get(txn, pg, &omp, NULL);
+						if (rc)
+							goto done;
+						if (my->mc_wlen[toggle] >= MDB_WBUF) {
+							rc = mdb_env_cthr_toggle(my, 1);
+							if (rc)
+								goto done;
+							toggle = my->mc_toggle;
+						}
+						mo = (MDB_page *)(my->mc_wbuf[toggle] + my->mc_wlen[toggle]);
+						memcpy(mo, omp, my->mc_env->me_psize);
+						mo->mp_pgno = my->mc_next_pgno;
+						my->mc_next_pgno += omp->mp_pages;
+						my->mc_wlen[toggle] += my->mc_env->me_psize;
+						if (omp->mp_pages > 1) {
+							my->mc_olen[toggle] = my->mc_env->me_psize * (omp->mp_pages - 1);
+							my->mc_over[toggle] = (char *)omp + my->mc_env->me_psize;
+							rc = mdb_env_cthr_toggle(my, 1);
+							if (rc)
+								goto done;
+							toggle = my->mc_toggle;
+						}
+						memcpy(NODEDATA(ni), &mo->mp_pgno, sizeof(pgno_t));
+					} else if (ni->mn_flags & F_SUBDATA) {
+						MDB_db db;
+
+						/* Need writable leaf */
+						if (mp != leaf) {
+							mc.mc_pg[mc.mc_top] = leaf;
+							mdb_page_copy(leaf, mp, my->mc_env->me_psize);
+							mp = leaf;
+							ni = NODEPTR(mp, i);
+						}
+
+						memcpy(&db, NODEDATA(ni), sizeof(db));
+						my->mc_toggle = toggle;
+						rc = mdb_env_cwalk(my, &db.md_root, ni->mn_flags & F_DUPDATA);
+						if (rc)
+							goto done;
+						toggle = my->mc_toggle;
+						memcpy(NODEDATA(ni), &db, sizeof(db));
+					}
+				}
+			}
+		} else {
+			mc.mc_ki[mc.mc_top]++;
+			if (mc.mc_ki[mc.mc_top] < n) {
+				pgno_t pg;
+again:
+				ni = NODEPTR(mp, mc.mc_ki[mc.mc_top]);
+				pg = NODEPGNO(ni);
+				rc = mdb_page_get(txn, pg, &mp, NULL);
+				if (rc)
+					goto done;
+				mc.mc_top++;
+				mc.mc_snum++;
+				mc.mc_ki[mc.mc_top] = 0;
+				if (IS_BRANCH(mp)) {
+					/* Whenever we advance to a sibling branch page,
+					 * we must proceed all the way down to its first leaf.
+					 */
+					mdb_page_copy(mc.mc_pg[mc.mc_top], mp, my->mc_env->me_psize);
+					goto again;
+				} else
+					mc.mc_pg[mc.mc_top] = mp;
+				continue;
+			}
+		}
+		if (my->mc_wlen[toggle] >= MDB_WBUF) {
+			rc = mdb_env_cthr_toggle(my, 1);
+			if (rc)
+				goto done;
+			toggle = my->mc_toggle;
+		}
+		mo = (MDB_page *)(my->mc_wbuf[toggle] + my->mc_wlen[toggle]);
+		mdb_page_copy(mo, mp, my->mc_env->me_psize);
+		mo->mp_pgno = my->mc_next_pgno++;
+		my->mc_wlen[toggle] += my->mc_env->me_psize;
+		if (mc.mc_top) {
+			/* Update parent if there is one */
+			ni = NODEPTR(mc.mc_pg[mc.mc_top-1], mc.mc_ki[mc.mc_top-1]);
+			SETPGNO(ni, mo->mp_pgno);
+			mdb_cursor_pop(&mc);
+		} else {
+			/* Otherwise we're done */
+			*pg = mo->mp_pgno;
+			break;
+		}
+	}
+done:
+	free(buf);
+	return rc;
+}
+
+	/** Copy environment with compaction. */
+static int ESECT
+mdb_env_copyfd1(MDB_env *env, HANDLE fd)
+{
+	MDB_meta *mm;
+	MDB_page *mp;
+	mdb_copy my;
+	MDB_txn *txn = NULL;
+	pthread_t thr;
+	int rc;
+
+#ifdef _WIN32
+	my.mc_mutex = CreateMutex(NULL, FALSE, NULL);
+	my.mc_cond = CreateEvent(NULL, FALSE, FALSE, NULL);
+	my.mc_wbuf[0] = _aligned_malloc(MDB_WBUF*2, env->me_os_psize);
+	if (my.mc_wbuf[0] == NULL)
+		return errno;
+#else
+	pthread_mutex_init(&my.mc_mutex, NULL);
+	pthread_cond_init(&my.mc_cond, NULL);
+#ifdef HAVE_MEMALIGN
+	my.mc_wbuf[0] = memalign(env->me_os_psize, MDB_WBUF*2);
+	if (my.mc_wbuf[0] == NULL)
+		return errno;
+#else
+	rc = posix_memalign((void **)&my.mc_wbuf[0], env->me_os_psize, MDB_WBUF*2);
+	if (rc)
+		return rc;
+#endif
+#endif
+	memset(my.mc_wbuf[0], 0, MDB_WBUF*2);
+	my.mc_wbuf[1] = my.mc_wbuf[0] + MDB_WBUF;
+	my.mc_wlen[0] = 0;
+	my.mc_wlen[1] = 0;
+	my.mc_olen[0] = 0;
+	my.mc_olen[1] = 0;
+	my.mc_next_pgno = 2;
+	my.mc_status = 0;
+	my.mc_new = 1;
+	my.mc_toggle = 0;
+	my.mc_env = env;
+	my.mc_fd = fd;
+	THREAD_CREATE(thr, mdb_env_copythr, &my);
+
+	rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
+	if (rc)
+		return rc;
+
+	mp = (MDB_page *)my.mc_wbuf[0];
+	memset(mp, 0, 2*env->me_psize);
+	mp->mp_pgno = 0;
+	mp->mp_flags = P_META;
+	mm = (MDB_meta *)METADATA(mp);
+	mdb_env_init_meta0(env, mm);
+	mm->mm_address = env->me_metas[0]->mm_address;
+
+	mp = (MDB_page *)(my.mc_wbuf[0] + env->me_psize);
+	mp->mp_pgno = 1;
+	mp->mp_flags = P_META;
+	*(MDB_meta *)METADATA(mp) = *mm;
+	mm = (MDB_meta *)METADATA(mp);
+
+	/* Count the number of free pages, subtract from lastpg to find
+	 * number of active pages
+	 */
+	{
+		MDB_ID freecount = 0;
+		MDB_cursor mc;
+		MDB_val key, data;
+		mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
+		while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)
+			freecount += *(MDB_ID *)data.mv_data;
+		freecount += txn->mt_dbs[0].md_branch_pages +
+			txn->mt_dbs[0].md_leaf_pages +
+			txn->mt_dbs[0].md_overflow_pages;
+
+		/* Set metapage 1 */
+		mm->mm_last_pg = txn->mt_next_pgno - freecount - 1;
+		mm->mm_dbs[1] = txn->mt_dbs[1];
+		mm->mm_dbs[1].md_root = mm->mm_last_pg;
+		mm->mm_txnid = 1;
+	}
+	my.mc_wlen[0] = env->me_psize * 2;
+	my.mc_txn = txn;
+	pthread_mutex_lock(&my.mc_mutex);
+	while(my.mc_new)
+		pthread_cond_wait(&my.mc_cond, &my.mc_mutex);
+	pthread_mutex_unlock(&my.mc_mutex);
+	rc = mdb_env_cwalk(&my, &txn->mt_dbs[1].md_root, 0);
+	if (rc == MDB_SUCCESS && my.mc_wlen[my.mc_toggle])
+		rc = mdb_env_cthr_toggle(&my, 1);
+	mdb_env_cthr_toggle(&my, -1);
+	pthread_mutex_lock(&my.mc_mutex);
+	while(my.mc_new)
+		pthread_cond_wait(&my.mc_cond, &my.mc_mutex);
+	pthread_mutex_unlock(&my.mc_mutex);
+	THREAD_FINISH(thr);
+
+	mdb_txn_abort(txn);
+#ifdef _WIN32
+	CloseHandle(my.mc_cond);
+	CloseHandle(my.mc_mutex);
+	_aligned_free(my.mc_wbuf[0]);
+#else
+	pthread_cond_destroy(&my.mc_cond);
+	pthread_mutex_destroy(&my.mc_mutex);
+	free(my.mc_wbuf[0]);
+#endif
+	return rc;
+}
+
+	/** Copy environment as-is. */
+static int ESECT
+mdb_env_copyfd0(MDB_env *env, HANDLE fd)
+{
+	MDB_txn *txn = NULL;
+	int rc;
+	size_t wsize;
+	char *ptr;
+#ifdef _WIN32
+	DWORD len, w2;
+#define DO_WRITE(rc, fd, ptr, w2, len)	rc = WriteFile(fd, ptr, w2, &len, NULL)
+#else
+	ssize_t len;
+	size_t w2;
+#define DO_WRITE(rc, fd, ptr, w2, len)	len = write(fd, ptr, w2); rc = (len >= 0)
+#endif
+
+	/* Do the lock/unlock of the reader mutex before starting the
+	 * write txn.  Otherwise other read txns could block writers.
+	 */
+	rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
+	if (rc)
+		return rc;
+
+	if (env->me_txns) {
+		/* We must start the actual read txn after blocking writers */
+		mdb_txn_reset0(txn, "reset-stage1");
+
+		/* Temporarily block writers until we snapshot the meta pages */
+		LOCK_MUTEX_W(env);
+
+		rc = mdb_txn_renew0(txn);
+		if (rc) {
+			UNLOCK_MUTEX_W(env);
+			goto leave;
+		}
+	}
+
+	wsize = env->me_psize * 2;
+	ptr = env->me_map;
+	w2 = wsize;
+	while (w2 > 0) {
+		DO_WRITE(rc, fd, ptr, w2, len);
+		if (!rc) {
+			rc = ErrCode();
+			break;
+		} else if (len > 0) {
+			rc = MDB_SUCCESS;
+			ptr += len;
+			w2 -= len;
+			continue;
+		} else {
+			/* Non-blocking or async handles are not supported */
+			rc = EIO;
+			break;
+		}
+	}
+	if (env->me_txns)
+		UNLOCK_MUTEX_W(env);
+
+	if (rc)
+		goto leave;
+
+	w2 = txn->mt_next_pgno * env->me_psize;
+#ifdef WIN32
+	{
+		LARGE_INTEGER fsize;
+		GetFileSizeEx(env->me_fd, &fsize);
+		if (w2 > fsize.QuadPart)
+			w2 = fsize.QuadPart;
+	}
+#else
+	{
+		struct stat st;
+		fstat(env->me_fd, &st);
+		if (w2 > (size_t)st.st_size)
+			w2 = st.st_size;
+	}
+#endif
+	wsize = w2 - wsize;
+	while (wsize > 0) {
+		if (wsize > MAX_WRITE)
+			w2 = MAX_WRITE;
+		else
+			w2 = wsize;
+		DO_WRITE(rc, fd, ptr, w2, len);
+		if (!rc) {
+			rc = ErrCode();
+			break;
+		} else if (len > 0) {
+			rc = MDB_SUCCESS;
+			ptr += len;
+			wsize -= len;
+			continue;
+		} else {
+			rc = EIO;
+			break;
+		}
+	}
+
+leave:
+	mdb_txn_abort(txn);
+	return rc;
+}
+
+int ESECT
+mdb_env_copyfd2(MDB_env *env, HANDLE fd, unsigned int flags)
+{
+	if (flags & MDB_CP_COMPACT)
+		return mdb_env_copyfd1(env, fd);
+	else
+		return mdb_env_copyfd0(env, fd);
+}
+
+int ESECT
+mdb_env_copyfd(MDB_env *env, HANDLE fd)
+{
+	return mdb_env_copyfd2(env, fd, 0);
+}
+
+int ESECT
+mdb_env_copy2(MDB_env *env, const char *path, unsigned int flags)
+{
+	int rc, len;
+	char *lpath;
+	HANDLE newfd = INVALID_HANDLE_VALUE;
+
+	if (env->me_flags & MDB_NOSUBDIR) {
+		lpath = (char *)path;
+	} else {
+		len = strlen(path);
+		len += sizeof(DATANAME);
+		lpath = malloc(len);
+		if (!lpath)
+			return ENOMEM;
+		sprintf(lpath, "%s" DATANAME, path);
+	}
+
+	/* The destination path must exist, but the destination file must not.
+	 * We don't want the OS to cache the writes, since the source data is
+	 * already in the OS cache.
+	 */
+#ifdef _WIN32
+	newfd = CreateFile(lpath, GENERIC_WRITE, 0, NULL, CREATE_NEW,
+				FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH, NULL);
+#else
+	newfd = open(lpath, O_WRONLY|O_CREAT|O_EXCL, 0666);
+#endif
+	if (newfd == INVALID_HANDLE_VALUE) {
+		rc = ErrCode();
+		goto leave;
+	}
+
+	if (env->me_psize >= env->me_os_psize) {
+#ifdef O_DIRECT
+	/* Set O_DIRECT if the file system supports it */
+	if ((rc = fcntl(newfd, F_GETFL)) != -1)
+		(void) fcntl(newfd, F_SETFL, rc | O_DIRECT);
+#endif
+#ifdef F_NOCACHE	/* __APPLE__ */
+	rc = fcntl(newfd, F_NOCACHE, 1);
+	if (rc) {
+		rc = ErrCode();
+		goto leave;
+	}
+#endif
+	}
+
+	rc = mdb_env_copyfd2(env, newfd, flags);
+
+leave:
+	if (!(env->me_flags & MDB_NOSUBDIR))
+		free(lpath);
+	if (newfd != INVALID_HANDLE_VALUE)
+		if (close(newfd) < 0 && rc == MDB_SUCCESS)
+			rc = ErrCode();
+
+	return rc;
+}
+
+int ESECT
+mdb_env_copy(MDB_env *env, const char *path)
+{
+	return mdb_env_copy2(env, path, 0);
+}
+
+int ESECT
+mdb_env_set_flags(MDB_env *env, unsigned int flag, int onoff)
+{
+	if ((flag & CHANGEABLE) != flag)
+		return EINVAL;
+	if (onoff)
+		env->me_flags |= flag;
+	else
+		env->me_flags &= ~flag;
+	return MDB_SUCCESS;
+}
+
+int ESECT
+mdb_env_get_flags(MDB_env *env, unsigned int *arg)
+{
+	if (!env || !arg)
+		return EINVAL;
+
+	*arg = env->me_flags;
+	return MDB_SUCCESS;
+}
+
+int ESECT
+mdb_env_set_userctx(MDB_env *env, void *ctx)
+{
+	if (!env)
+		return EINVAL;
+	env->me_userctx = ctx;
+	return MDB_SUCCESS;
+}
+
+void * ESECT
+mdb_env_get_userctx(MDB_env *env)
+{
+	return env ? env->me_userctx : NULL;
+}
+
+int ESECT
+mdb_env_set_assert(MDB_env *env, MDB_assert_func *func)
+{
+	if (!env)
+		return EINVAL;
+#ifndef NDEBUG
+	env->me_assert_func = func;
+#endif
+	return MDB_SUCCESS;
+}
+
+int ESECT
+mdb_env_get_path(MDB_env *env, const char **arg)
+{
+	if (!env || !arg)
+		return EINVAL;
+
+	*arg = env->me_path;
+	return MDB_SUCCESS;
+}
+
+int ESECT
+mdb_env_get_fd(MDB_env *env, mdb_filehandle_t *arg)
+{
+	if (!env || !arg)
+		return EINVAL;
+
+	*arg = env->me_fd;
+	return MDB_SUCCESS;
+}
+
+/** Common code for #mdb_stat() and #mdb_env_stat().
+ * @param[in] env the environment to operate in.
+ * @param[in] db the #MDB_db record containing the stats to return.
+ * @param[out] arg the address of an #MDB_stat structure to receive the stats.
+ * @return 0, this function always succeeds.
+ */
+static int ESECT
+mdb_stat0(MDB_env *env, MDB_db *db, MDB_stat *arg)
+{
+	arg->ms_psize = env->me_psize;
+	arg->ms_depth = db->md_depth;
+	arg->ms_branch_pages = db->md_branch_pages;
+	arg->ms_leaf_pages = db->md_leaf_pages;
+	arg->ms_overflow_pages = db->md_overflow_pages;
+	arg->ms_entries = db->md_entries;
+
+	return MDB_SUCCESS;
+}
+
+int ESECT
+mdb_env_stat(MDB_env *env, MDB_stat *arg)
+{
+	int toggle;
+
+	if (env == NULL || arg == NULL)
+		return EINVAL;
+
+	toggle = mdb_env_pick_meta(env);
+
+	return mdb_stat0(env, &env->me_metas[toggle]->mm_dbs[MAIN_DBI], arg);
+}
+
+int ESECT
+mdb_env_info(MDB_env *env, MDB_envinfo *arg)
+{
+	int toggle;
+
+	if (env == NULL || arg == NULL)
+		return EINVAL;
+
+	toggle = mdb_env_pick_meta(env);
+	arg->me_mapaddr = env->me_metas[toggle]->mm_address;
+	arg->me_mapsize = env->me_mapsize;
+	arg->me_maxreaders = env->me_maxreaders;
+
+	/* me_numreaders may be zero if this process never used any readers. Use
+	 * the shared numreader count if it exists.
+	 */
+	arg->me_numreaders = env->me_txns ? env->me_txns->mti_numreaders : env->me_numreaders;
+
+	arg->me_last_pgno = env->me_metas[toggle]->mm_last_pg;
+	arg->me_last_txnid = env->me_metas[toggle]->mm_txnid;
+	return MDB_SUCCESS;
+}
+
+/** Set the default comparison functions for a database.
+ * Called immediately after a database is opened to set the defaults.
+ * The user can then override them with #mdb_set_compare() or
+ * #mdb_set_dupsort().
+ * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+ * @param[in] dbi A database handle returned by #mdb_dbi_open()
+ */
+static void
+mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi)
+{
+	uint16_t f = txn->mt_dbs[dbi].md_flags;
+
+	txn->mt_dbxs[dbi].md_cmp =
+		(f & MDB_REVERSEKEY) ? mdb_cmp_memnr :
+		(f & MDB_INTEGERKEY) ? mdb_cmp_cint  : mdb_cmp_memn;
+
+	txn->mt_dbxs[dbi].md_dcmp =
+		!(f & MDB_DUPSORT) ? 0 :
+		((f & MDB_INTEGERDUP)
+		 ? ((f & MDB_DUPFIXED)   ? mdb_cmp_int   : mdb_cmp_cint)
+		 : ((f & MDB_REVERSEDUP) ? mdb_cmp_memnr : mdb_cmp_memn));
+}
+
+int mdb_dbi_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)
+{
+	MDB_val key, data;
+	MDB_dbi i;
+	MDB_cursor mc;
+	MDB_db dummy;
+	int rc, dbflag, exact;
+	unsigned int unused = 0, seq;
+	size_t len;
+
+	if (txn->mt_dbxs[FREE_DBI].md_cmp == NULL) {
+		mdb_default_cmp(txn, FREE_DBI);
+	}
+
+	if ((flags & VALID_FLAGS) != flags)
+		return EINVAL;
+	if (txn->mt_flags & MDB_TXN_ERROR)
+		return MDB_BAD_TXN;
+
+	/* main DB? */
+	if (!name) {
+		*dbi = MAIN_DBI;
+		if (flags & PERSISTENT_FLAGS) {
+			uint16_t f2 = flags & PERSISTENT_FLAGS;
+			/* make sure flag changes get committed */
+			if ((txn->mt_dbs[MAIN_DBI].md_flags | f2) != txn->mt_dbs[MAIN_DBI].md_flags) {
+				txn->mt_dbs[MAIN_DBI].md_flags |= f2;
+				txn->mt_flags |= MDB_TXN_DIRTY;
+			}
+		}
+		mdb_default_cmp(txn, MAIN_DBI);
+		return MDB_SUCCESS;
+	}
+
+	if (txn->mt_dbxs[MAIN_DBI].md_cmp == NULL) {
+		mdb_default_cmp(txn, MAIN_DBI);
+	}
+
+	/* Is the DB already open? */
+	len = strlen(name);
+	for (i=2; i<txn->mt_numdbs; i++) {
+		if (!txn->mt_dbxs[i].md_name.mv_size) {
+			/* Remember this free slot */
+			if (!unused) unused = i;
+			continue;
+		}
+		if (len == txn->mt_dbxs[i].md_name.mv_size &&
+			!strncmp(name, txn->mt_dbxs[i].md_name.mv_data, len)) {
+			*dbi = i;
+			return MDB_SUCCESS;
+		}
+	}
+
+	/* If no free slot and max hit, fail */
+	if (!unused && txn->mt_numdbs >= txn->mt_env->me_maxdbs)
+		return MDB_DBS_FULL;
+
+	/* Cannot mix named databases with some mainDB flags */
+	if (txn->mt_dbs[MAIN_DBI].md_flags & (MDB_DUPSORT|MDB_INTEGERKEY))
+		return (flags & MDB_CREATE) ? MDB_INCOMPATIBLE : MDB_NOTFOUND;
+
+	/* Find the DB info */
+	dbflag = DB_NEW|DB_VALID;
+	exact = 0;
+	key.mv_size = len;
+	key.mv_data = (void *)name;
+	mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
+	rc = mdb_cursor_set(&mc, &key, &data, MDB_SET, &exact);
+	if (rc == MDB_SUCCESS) {
+		/* make sure this is actually a DB */
+		MDB_node *node = NODEPTR(mc.mc_pg[mc.mc_top], mc.mc_ki[mc.mc_top]);
+		if (!(node->mn_flags & F_SUBDATA))
+			return MDB_INCOMPATIBLE;
+	} else if (rc == MDB_NOTFOUND && (flags & MDB_CREATE)) {
+		/* Create if requested */
+		data.mv_size = sizeof(MDB_db);
+		data.mv_data = &dummy;
+		memset(&dummy, 0, sizeof(dummy));
+		dummy.md_root = P_INVALID;
+		dummy.md_flags = flags & PERSISTENT_FLAGS;
+		rc = mdb_cursor_put(&mc, &key, &data, F_SUBDATA);
+		dbflag |= DB_DIRTY;
+	}
+
+	/* OK, got info, add to table */
+	if (rc == MDB_SUCCESS) {
+		unsigned int slot = unused ? unused : txn->mt_numdbs;
+		txn->mt_dbxs[slot].md_name.mv_data = strdup(name);
+		txn->mt_dbxs[slot].md_name.mv_size = len;
+		txn->mt_dbxs[slot].md_rel = NULL;
+		txn->mt_dbflags[slot] = dbflag;
+		/* txn-> and env-> are the same in read txns, use
+		 * tmp variable to avoid undefined assignment
+		 */
+		seq = ++txn->mt_env->me_dbiseqs[slot];
+		txn->mt_dbiseqs[slot] = seq;
+
+		memcpy(&txn->mt_dbs[slot], data.mv_data, sizeof(MDB_db));
+		*dbi = slot;
+		mdb_default_cmp(txn, slot);
+		if (!unused) {
+			txn->mt_numdbs++;
+		}
+	}
+
+	return rc;
+}
+
+int mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *arg)
+{
+	if (!arg || !TXN_DBI_EXIST(txn, dbi))
+		return EINVAL;
+
+	if (txn->mt_flags & MDB_TXN_ERROR)
+		return MDB_BAD_TXN;
+
+	if (txn->mt_dbflags[dbi] & DB_STALE) {
+		MDB_cursor mc;
+		MDB_xcursor mx;
+		/* Stale, must read the DB's root. cursor_init does it for us. */
+		mdb_cursor_init(&mc, txn, dbi, &mx);
+	}
+	return mdb_stat0(txn->mt_env, &txn->mt_dbs[dbi], arg);
+}
+
+void mdb_dbi_close(MDB_env *env, MDB_dbi dbi)
+{
+	char *ptr;
+	if (dbi <= MAIN_DBI || dbi >= env->me_maxdbs)
+		return;
+	ptr = env->me_dbxs[dbi].md_name.mv_data;
+	/* If there was no name, this was already closed */
+	if (ptr) {
+		env->me_dbxs[dbi].md_name.mv_data = NULL;
+		env->me_dbxs[dbi].md_name.mv_size = 0;
+		env->me_dbflags[dbi] = 0;
+		env->me_dbiseqs[dbi]++;
+		free(ptr);
+	}
+}
+
+int mdb_dbi_flags(MDB_txn *txn, MDB_dbi dbi, unsigned int *flags)
+{
+	/* We could return the flags for the FREE_DBI too but what's the point? */
+	if (dbi == FREE_DBI || !TXN_DBI_EXIST(txn, dbi))
+		return EINVAL;
+	*flags = txn->mt_dbs[dbi].md_flags & PERSISTENT_FLAGS;
+	return MDB_SUCCESS;
+}
+
+/** Add all the DB's pages to the free list.
+ * @param[in] mc Cursor on the DB to free.
+ * @param[in] subs non-Zero to check for sub-DBs in this DB.
+ * @return 0 on success, non-zero on failure.
+ */
+static int
+mdb_drop0(MDB_cursor *mc, int subs)
+{
+	int rc;
+
+	rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);
+	if (rc == MDB_SUCCESS) {
+		MDB_txn *txn = mc->mc_txn;
+		MDB_node *ni;
+		MDB_cursor mx;
+		unsigned int i;
+
+		/* LEAF2 pages have no nodes, cannot have sub-DBs */
+		if (IS_LEAF2(mc->mc_pg[mc->mc_top]))
+			mdb_cursor_pop(mc);
+
+		mdb_cursor_copy(mc, &mx);
+		while (mc->mc_snum > 0) {
+			MDB_page *mp = mc->mc_pg[mc->mc_top];
+			unsigned n = NUMKEYS(mp);
+			if (IS_LEAF(mp)) {
+				for (i=0; i<n; i++) {
+					ni = NODEPTR(mp, i);
+					if (ni->mn_flags & F_BIGDATA) {
+						MDB_page *omp;
+						pgno_t pg;
+						memcpy(&pg, NODEDATA(ni), sizeof(pg));
+						rc = mdb_page_get(txn, pg, &omp, NULL);
+						if (rc != 0)
+							goto done;
+						mdb_cassert(mc, IS_OVERFLOW(omp));
+						rc = mdb_midl_append_range(&txn->mt_free_pgs,
+							pg, omp->mp_pages);
+						if (rc)
+							goto done;
+					} else if (subs && (ni->mn_flags & F_SUBDATA)) {
+						mdb_xcursor_init1(mc, ni);
+						rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
+						if (rc)
+							goto done;
+					}
+				}
+			} else {
+				if ((rc = mdb_midl_need(&txn->mt_free_pgs, n)) != 0)
+					goto done;
+				for (i=0; i<n; i++) {
+					pgno_t pg;
+					ni = NODEPTR(mp, i);
+					pg = NODEPGNO(ni);
+					/* free it */
+					mdb_midl_xappend(txn->mt_free_pgs, pg);
+				}
+			}
+			if (!mc->mc_top)
+				break;
+			mc->mc_ki[mc->mc_top] = i;
+			rc = mdb_cursor_sibling(mc, 1);
+			if (rc) {
+				if (rc != MDB_NOTFOUND)
+					goto done;
+				/* no more siblings, go back to beginning
+				 * of previous level.
+				 */
+				mdb_cursor_pop(mc);
+				mc->mc_ki[0] = 0;
+				for (i=1; i<mc->mc_snum; i++) {
+					mc->mc_ki[i] = 0;
+					mc->mc_pg[i] = mx.mc_pg[i];
+				}
+			}
+		}
+		/* free it */
+		rc = mdb_midl_append(&txn->mt_free_pgs, mc->mc_db->md_root);
+done:
+		if (rc)
+			txn->mt_flags |= MDB_TXN_ERROR;
+	} else if (rc == MDB_NOTFOUND) {
+		rc = MDB_SUCCESS;
+	}
+	return rc;
+}
+
+int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)
+{
+	MDB_cursor *mc, *m2;
+	int rc;
+
+	if ((unsigned)del > 1 || dbi == FREE_DBI || !TXN_DBI_EXIST(txn, dbi))
+		return EINVAL;
+
+	if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
+		return EACCES;
+
+	if (dbi > MAIN_DBI && TXN_DBI_CHANGED(txn, dbi))
+		return MDB_BAD_DBI;
+
+	rc = mdb_cursor_open(txn, dbi, &mc);
+	if (rc)
+		return rc;
+
+	rc = mdb_drop0(mc, mc->mc_db->md_flags & MDB_DUPSORT);
+	/* Invalidate the dropped DB's cursors */
+	for (m2 = txn->mt_cursors[dbi]; m2; m2 = m2->mc_next)
+		m2->mc_flags &= ~(C_INITIALIZED|C_EOF);
+	if (rc)
+		goto leave;
+
+	/* Can't delete the main DB */
+	if (del && dbi > MAIN_DBI) {
+		rc = mdb_del0(txn, MAIN_DBI, &mc->mc_dbx->md_name, NULL, 0);
+		if (!rc) {
+			txn->mt_dbflags[dbi] = DB_STALE;
+			mdb_dbi_close(txn->mt_env, dbi);
+		} else {
+			txn->mt_flags |= MDB_TXN_ERROR;
+		}
+	} else {
+		/* reset the DB record, mark it dirty */
+		txn->mt_dbflags[dbi] |= DB_DIRTY;
+		txn->mt_dbs[dbi].md_depth = 0;
+		txn->mt_dbs[dbi].md_branch_pages = 0;
+		txn->mt_dbs[dbi].md_leaf_pages = 0;
+		txn->mt_dbs[dbi].md_overflow_pages = 0;
+		txn->mt_dbs[dbi].md_entries = 0;
+		txn->mt_dbs[dbi].md_root = P_INVALID;
+
+		txn->mt_flags |= MDB_TXN_DIRTY;
+	}
+leave:
+	mdb_cursor_close(mc);
+	return rc;
+}
+
+int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
+{
+	if (dbi == FREE_DBI || !TXN_DBI_EXIST(txn, dbi))
+		return EINVAL;
+
+	txn->mt_dbxs[dbi].md_cmp = cmp;
+	return MDB_SUCCESS;
+}
+
+int mdb_set_dupsort(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
+{
+	if (dbi == FREE_DBI || !TXN_DBI_EXIST(txn, dbi))
+		return EINVAL;
+
+	txn->mt_dbxs[dbi].md_dcmp = cmp;
+	return MDB_SUCCESS;
+}
+
+int mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel)
+{
+	if (dbi == FREE_DBI || !TXN_DBI_EXIST(txn, dbi))
+		return EINVAL;
+
+	txn->mt_dbxs[dbi].md_rel = rel;
+	return MDB_SUCCESS;
+}
+
+int mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx)
+{
+	if (dbi == FREE_DBI || !TXN_DBI_EXIST(txn, dbi))
+		return EINVAL;
+
+	txn->mt_dbxs[dbi].md_relctx = ctx;
+	return MDB_SUCCESS;
+}
+
+int ESECT
+mdb_env_get_maxkeysize(MDB_env *env)
+{
+	return ENV_MAXKEY(env);
+}
+
+int ESECT
+mdb_reader_list(MDB_env *env, MDB_msg_func *func, void *ctx)
+{
+	unsigned int i, rdrs;
+	MDB_reader *mr;
+	char buf[64];
+	int rc = 0, first = 1;
+
+	if (!env || !func)
+		return -1;
+	if (!env->me_txns) {
+		return func("(no reader locks)\n", ctx);
+	}
+	rdrs = env->me_txns->mti_numreaders;
+	mr = env->me_txns->mti_readers;
+	for (i=0; i<rdrs; i++) {
+		if (mr[i].mr_pid) {
+			txnid_t	txnid = mr[i].mr_txnid;
+			sprintf(buf, txnid == (txnid_t)-1 ?
+				"%10d %"Z"x -\n" : "%10d %"Z"x %"Z"u\n",
+				(int)mr[i].mr_pid, (size_t)mr[i].mr_tid, txnid);
+			if (first) {
+				first = 0;
+				rc = func("    pid     thread     txnid\n", ctx);
+				if (rc < 0)
+					break;
+			}
+			rc = func(buf, ctx);
+			if (rc < 0)
+				break;
+		}
+	}
+	if (first) {
+		rc = func("(no active readers)\n", ctx);
+	}
+	return rc;
+}
+
+/** Insert pid into list if not already present.
+ * return -1 if already present.
+ */
+static int ESECT
+mdb_pid_insert(MDB_PID_T *ids, MDB_PID_T pid)
+{
+	/* binary search of pid in list */
+	unsigned base = 0;
+	unsigned cursor = 1;
+	int val = 0;
+	unsigned n = ids[0];
+
+	while( 0 < n ) {
+		unsigned pivot = n >> 1;
+		cursor = base + pivot + 1;
+		val = pid - ids[cursor];
+
+		if( val < 0 ) {
+			n = pivot;
+
+		} else if ( val > 0 ) {
+			base = cursor;
+			n -= pivot + 1;
+
+		} else {
+			/* found, so it's a duplicate */
+			return -1;
+		}
+	}
+
+	if( val > 0 ) {
+		++cursor;
+	}
+	ids[0]++;
+	for (n = ids[0]; n > cursor; n--)
+		ids[n] = ids[n-1];
+	ids[n] = pid;
+	return 0;
+}
+
+int ESECT
+mdb_reader_check(MDB_env *env, int *dead)
+{
+	unsigned int i, j, rdrs;
+	MDB_reader *mr;
+	MDB_PID_T *pids, pid;
+	int count = 0;
+
+	if (!env)
+		return EINVAL;
+	if (dead)
+		*dead = 0;
+	if (!env->me_txns)
+		return MDB_SUCCESS;
+	rdrs = env->me_txns->mti_numreaders;
+	pids = malloc((rdrs+1) * sizeof(MDB_PID_T));
+	if (!pids)
+		return ENOMEM;
+	pids[0] = 0;
+	mr = env->me_txns->mti_readers;
+	for (i=0; i<rdrs; i++) {
+		if (mr[i].mr_pid && mr[i].mr_pid != env->me_pid) {
+			pid = mr[i].mr_pid;
+			if (mdb_pid_insert(pids, pid) == 0) {
+				if (!mdb_reader_pid(env, Pidcheck, pid)) {
+					LOCK_MUTEX_R(env);
+					/* Recheck, a new process may have reused pid */
+					if (!mdb_reader_pid(env, Pidcheck, pid)) {
+						for (j=i; j<rdrs; j++)
+							if (mr[j].mr_pid == pid) {
+								DPRINTF(("clear stale reader pid %u txn %"Z"d",
+									(unsigned) pid, mr[j].mr_txnid));
+								mr[j].mr_pid = 0;
+								count++;
+							}
+					}
+					UNLOCK_MUTEX_R(env);
+				}
+			}
+		}
+	}
+	free(pids);
+	if (dead)
+		*dead = count;
+	return MDB_SUCCESS;
+}
+/** @} */
diff --git a/external/db_drivers/liblmdb/mdb_copy.1 b/external/db_drivers/liblmdb32/mdb_copy.1
index 094b26056..094b26056 100644
--- a/external/db_drivers/liblmdb/mdb_copy.1
+++ b/external/db_drivers/liblmdb32/mdb_copy.1
diff --git a/external/db_drivers/liblmdb32/mdb_copy.c b/external/db_drivers/liblmdb32/mdb_copy.c
new file mode 100644
index 000000000..e7f965c03
--- /dev/null
+++ b/external/db_drivers/liblmdb32/mdb_copy.c
@@ -0,0 +1,82 @@
+/* mdb_copy.c - memory-mapped database backup tool */
+/*
+ * Copyright 2012 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+#ifdef _WIN32
+#include <windows.h>
+#define	MDB_STDOUT	GetStdHandle(STD_OUTPUT_HANDLE)
+#else
+#define	MDB_STDOUT	1
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include "lmdb.h"
+
+static void
+sighandle(int sig)
+{
+}
+
+int main(int argc,char * argv[])
+{
+	int rc;
+	MDB_env *env;
+	const char *progname = argv[0], *act;
+	unsigned flags = MDB_RDONLY;
+	unsigned cpflags = 0;
+
+	for (; argc > 1 && argv[1][0] == '-'; argc--, argv++) {
+		if (argv[1][1] == 'n' && argv[1][2] == '\0')
+			flags |= MDB_NOSUBDIR;
+		else if (argv[1][1] == 'c' && argv[1][2] == '\0')
+			cpflags |= MDB_CP_COMPACT;
+		else if (argv[1][1] == 'V' && argv[1][2] == '\0') {
+			printf("%s\n", MDB_VERSION_STRING);
+			exit(0);
+		} else
+			argc = 0;
+	}
+
+	if (argc<2 || argc>3) {
+		fprintf(stderr, "usage: %s [-V] [-c] [-n] srcpath [dstpath]\n", progname);
+		exit(EXIT_FAILURE);
+	}
+
+#ifdef SIGPIPE
+	signal(SIGPIPE, sighandle);
+#endif
+#ifdef SIGHUP
+	signal(SIGHUP, sighandle);
+#endif
+	signal(SIGINT, sighandle);
+	signal(SIGTERM, sighandle);
+
+	act = "opening environment";
+	rc = mdb_env_create(&env);
+	if (rc == MDB_SUCCESS) {
+		rc = mdb_env_open(env, argv[1], flags, 0664);
+	}
+	if (rc == MDB_SUCCESS) {
+		act = "copying";
+		if (argc == 2)
+			rc = mdb_env_copyfd2(env, MDB_STDOUT, cpflags);
+		else
+			rc = mdb_env_copy2(env, argv[2], cpflags);
+	}
+	if (rc)
+		fprintf(stderr, "%s: %s failed, error %d (%s)\n",
+			progname, act, rc, mdb_strerror(rc));
+	mdb_env_close(env);
+
+	return rc ? EXIT_FAILURE : EXIT_SUCCESS;
+}
diff --git a/external/db_drivers/liblmdb/mdb_dump.1 b/external/db_drivers/liblmdb32/mdb_dump.1
index 6fcc93081..6fcc93081 100644
--- a/external/db_drivers/liblmdb/mdb_dump.1
+++ b/external/db_drivers/liblmdb32/mdb_dump.1
diff --git a/external/db_drivers/liblmdb/mdb_dump.c b/external/db_drivers/liblmdb32/mdb_dump.c
index 0eb85fd20..0eb85fd20 100644
--- a/external/db_drivers/liblmdb/mdb_dump.c
+++ b/external/db_drivers/liblmdb32/mdb_dump.c
diff --git a/external/db_drivers/liblmdb/mdb_load.1 b/external/db_drivers/liblmdb32/mdb_load.1
index 728024010..728024010 100644
--- a/external/db_drivers/liblmdb/mdb_load.1
+++ b/external/db_drivers/liblmdb32/mdb_load.1
diff --git a/external/db_drivers/liblmdb/mdb_load.c b/external/db_drivers/liblmdb32/mdb_load.c
index e0d95e13c..e0d95e13c 100644
--- a/external/db_drivers/liblmdb/mdb_load.c
+++ b/external/db_drivers/liblmdb32/mdb_load.c
diff --git a/external/db_drivers/liblmdb/mdb_stat.1 b/external/db_drivers/liblmdb32/mdb_stat.1
index 3d8d461d9..3d8d461d9 100644
--- a/external/db_drivers/liblmdb/mdb_stat.1
+++ b/external/db_drivers/liblmdb32/mdb_stat.1
diff --git a/external/db_drivers/liblmdb/mdb_stat.c b/external/db_drivers/liblmdb32/mdb_stat.c
index 1e9229296..1e9229296 100644
--- a/external/db_drivers/liblmdb/mdb_stat.c
+++ b/external/db_drivers/liblmdb32/mdb_stat.c
diff --git a/external/db_drivers/liblmdb/midl.c b/external/db_drivers/liblmdb32/midl.c
index 88a3aff10..88a3aff10 100644
--- a/external/db_drivers/liblmdb/midl.c
+++ b/external/db_drivers/liblmdb32/midl.c
diff --git a/external/db_drivers/liblmdb32/midl.h b/external/db_drivers/liblmdb32/midl.h
new file mode 100644
index 000000000..f23d7d3f3
--- /dev/null
+++ b/external/db_drivers/liblmdb32/midl.h
@@ -0,0 +1,190 @@
+/**	@file midl.h
+ *	@brief LMDB ID List header file.
+ *
+ *	This file was originally part of back-bdb but has been
+ *	modified for use in libmdb. Most of the macros defined
+ *	in this file are unused, just left over from the original.
+ *
+ *	This file is only used internally in libmdb and its definitions
+ *	are not exposed publicly.
+ */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2000-2014 The OpenLDAP Foundation.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+#ifndef _MDB_MIDL_H_
+#define _MDB_MIDL_H_
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** @defgroup internal	LMDB Internals
+ *	@{
+ */
+
+/** @defgroup idls	ID List Management
+ *	@{
+ */
+	/** A generic unsigned ID number. These were entryIDs in back-bdb.
+	 *	Preferably it should have the same size as a pointer.
+	 */
+typedef size_t MDB_ID;
+
+	/** An IDL is an ID List, a sorted array of IDs. The first
+	 * element of the array is a counter for how many actual
+	 * IDs are in the list. In the original back-bdb code, IDLs are
+	 * sorted in ascending order. For libmdb IDLs are sorted in
+	 * descending order.
+	 */
+typedef MDB_ID *MDB_IDL;
+
+/* IDL sizes - likely should be even bigger
+ *   limiting factors: sizeof(ID), thread stack size
+ */
+#ifdef VL32
+#define	MDB_IDL_LOGN	10	/* DB_SIZE is 2^10, UM_SIZE is 2^11 */
+#else
+#define	MDB_IDL_LOGN	16	/* DB_SIZE is 2^16, UM_SIZE is 2^17 */
+#endif
+#define MDB_IDL_DB_SIZE		(1<<MDB_IDL_LOGN)
+#define MDB_IDL_UM_SIZE		(1<<(MDB_IDL_LOGN+1))
+
+#define MDB_IDL_DB_MAX		(MDB_IDL_DB_SIZE-1)
+#define MDB_IDL_UM_MAX		(MDB_IDL_UM_SIZE-1)
+
+#define MDB_IDL_SIZEOF(ids)		(((ids)[0]+1) * sizeof(MDB_ID))
+#define MDB_IDL_IS_ZERO(ids) ( (ids)[0] == 0 )
+#define MDB_IDL_CPY( dst, src ) (memcpy( dst, src, MDB_IDL_SIZEOF( src ) ))
+#define MDB_IDL_FIRST( ids )	( (ids)[1] )
+#define MDB_IDL_LAST( ids )		( (ids)[(ids)[0]] )
+
+	/** Current max length of an #mdb_midl_alloc()ed IDL */
+#define MDB_IDL_ALLOCLEN( ids )	( (ids)[-1] )
+
+	/** Append ID to IDL. The IDL must be big enough. */
+#define mdb_midl_xappend(idl, id) do { \
+		MDB_ID *xidl = (idl), xlen = ++(xidl[0]); \
+		xidl[xlen] = (id); \
+	} while (0)
+
+	/** Search for an ID in an IDL.
+	 * @param[in] ids	The IDL to search.
+	 * @param[in] id	The ID to search for.
+	 * @return	The index of the first ID greater than or equal to \b id.
+	 */
+unsigned mdb_midl_search( MDB_IDL ids, MDB_ID id );
+
+	/** Allocate an IDL.
+	 * Allocates memory for an IDL of the given size.
+	 * @return	IDL on success, NULL on failure.
+	 */
+MDB_IDL mdb_midl_alloc(int num);
+
+	/** Free an IDL.
+	 * @param[in] ids	The IDL to free.
+	 */
+void mdb_midl_free(MDB_IDL ids);
+
+	/** Shrink an IDL.
+	 * Return the IDL to the default size if it has grown larger.
+	 * @param[in,out] idp	Address of the IDL to shrink.
+	 * @return	0 on no change, non-zero if shrunk.
+	 */
+int mdb_midl_shrink(MDB_IDL *idp);
+
+	/** Make room for num additional elements in an IDL.
+	 * @param[in,out] idp	Address of the IDL.
+	 * @param[in] num	Number of elements to make room for.
+	 * @return	0 on success, ENOMEM on failure.
+	 */
+int mdb_midl_need(MDB_IDL *idp, unsigned num);
+
+	/** Append an ID onto an IDL.
+	 * @param[in,out] idp	Address of the IDL to append to.
+	 * @param[in] id	The ID to append.
+	 * @return	0 on success, ENOMEM if the IDL is too large.
+	 */
+int mdb_midl_append( MDB_IDL *idp, MDB_ID id );
+
+	/** Append an IDL onto an IDL.
+	 * @param[in,out] idp	Address of the IDL to append to.
+	 * @param[in] app	The IDL to append.
+	 * @return	0 on success, ENOMEM if the IDL is too large.
+	 */
+int mdb_midl_append_list( MDB_IDL *idp, MDB_IDL app );
+
+	/** Append an ID range onto an IDL.
+	 * @param[in,out] idp	Address of the IDL to append to.
+	 * @param[in] id	The lowest ID to append.
+	 * @param[in] n		Number of IDs to append.
+	 * @return	0 on success, ENOMEM if the IDL is too large.
+	 */
+int mdb_midl_append_range( MDB_IDL *idp, MDB_ID id, unsigned n );
+
+	/** Merge an IDL onto an IDL. The destination IDL must be big enough.
+	 * @param[in] idl	The IDL to merge into.
+	 * @param[in] merge	The IDL to merge.
+	 */
+void mdb_midl_xmerge( MDB_IDL idl, MDB_IDL merge );
+
+	/** Sort an IDL.
+	 * @param[in,out] ids	The IDL to sort.
+	 */
+void mdb_midl_sort( MDB_IDL ids );
+
+	/** An ID2 is an ID/pointer pair.
+	 */
+typedef struct MDB_ID2 {
+	MDB_ID mid;		/**< The ID */
+	void *mptr;		/**< The pointer */
+} MDB_ID2;
+
+	/** An ID2L is an ID2 List, a sorted array of ID2s.
+	 * The first element's \b mid member is a count of how many actual
+	 * elements are in the array. The \b mptr member of the first element is unused.
+	 * The array is sorted in ascending order by \b mid.
+	 */
+typedef MDB_ID2 *MDB_ID2L;
+
+	/** Search for an ID in an ID2L.
+	 * @param[in] ids	The ID2L to search.
+	 * @param[in] id	The ID to search for.
+	 * @return	The index of the first ID2 whose \b mid member is greater than or equal to \b id.
+	 */
+unsigned mdb_mid2l_search( MDB_ID2L ids, MDB_ID id );
+
+
+	/** Insert an ID2 into a ID2L.
+	 * @param[in,out] ids	The ID2L to insert into.
+	 * @param[in] id	The ID2 to insert.
+	 * @return	0 on success, -1 if the ID was already present in the ID2L.
+	 */
+int mdb_mid2l_insert( MDB_ID2L ids, MDB_ID2 *id );
+
+	/** Append an ID2 into a ID2L.
+	 * @param[in,out] ids	The ID2L to append into.
+	 * @param[in] id	The ID2 to append.
+	 * @return	0 on success, -2 if the ID2L is too big.
+	 */
+int mdb_mid2l_append( MDB_ID2L ids, MDB_ID2 *id );
+
+/** @} */
+/** @} */
+#ifdef __cplusplus
+}
+#endif
+#endif	/* _MDB_MIDL_H_ */
diff --git a/external/db_drivers/liblmdb32/mtest.c b/external/db_drivers/liblmdb32/mtest.c
new file mode 100644
index 000000000..2d4e5e832
--- /dev/null
+++ b/external/db_drivers/liblmdb32/mtest.c
@@ -0,0 +1,173 @@
+/* mtest.c - memory-mapped database tester/toy */
+/*
+ * Copyright 2011-2014 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include "lmdb.h"
+
+#define E(expr) CHECK((rc = (expr)) == MDB_SUCCESS, #expr)
+#define RES(err, expr) ((rc = expr) == (err) || (CHECK(!rc, #expr), 0))
+#define CHECK(test, msg) ((test) ? (void)0 : ((void)fprintf(stderr, \
+	"%s:%d: %s: %s\n", __FILE__, __LINE__, msg, mdb_strerror(rc)), abort()))
+
+int main(int argc,char * argv[])
+{
+	int i = 0, j = 0, rc;
+	MDB_env *env;
+	MDB_dbi dbi;
+	MDB_val key, data;
+	MDB_txn *txn;
+	MDB_stat mst;
+	MDB_cursor *cursor, *cur2;
+	MDB_cursor_op op;
+	int count;
+	int *values;
+	char sval[32] = "";
+
+	srand(time(NULL));
+
+	    count = (rand()%384) + 64;
+	    values = (int *)malloc(count*sizeof(int));
+
+	    for(i = 0;i<count;i++) {
+			values[i] = rand()%1024;
+	    }
+    
+		E(mdb_env_create(&env));
+		E(mdb_env_set_mapsize(env, 10485760));
+		E(mdb_env_open(env, "./testdb", 0 /* MDB_FIXEDMAP |MDB_NOSYNC*/, 0664));
+		E(mdb_txn_begin(env, NULL, 0, &txn));
+		E(mdb_open(txn, NULL, 0, &dbi));
+   
+		key.mv_size = sizeof(int);
+		key.mv_data = sval;
+		data.mv_size = sizeof(sval);
+		data.mv_data = sval;
+
+		printf("Adding %d values\n", count);
+	    for (i=0;i<count;i++) {	
+			sprintf(sval, "%03x %d foo bar", values[i], values[i]);
+			if (RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NOOVERWRITE))) {
+				j++;
+				data.mv_size = sizeof(sval);
+				data.mv_data = sval;
+			}
+	    }
+		if (j) printf("%d duplicates skipped\n", j);
+		E(mdb_txn_commit(txn));
+		E(mdb_env_stat(env, &mst));
+
+		E(mdb_txn_begin(env, NULL, 1, &txn));
+		E(mdb_cursor_open(txn, dbi, &cursor));
+		while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+			printf("key: %p %.*s, data: %p %.*s\n",
+				key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
+				data.mv_data, (int) data.mv_size, (char *) data.mv_data);
+		}
+		CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+		mdb_cursor_close(cursor);
+		mdb_txn_abort(txn);
+
+		j=0;
+		key.mv_data = sval;
+	    for (i= count - 1; i > -1; i-= (rand()%5)) {
+			j++;
+			txn=NULL;
+			E(mdb_txn_begin(env, NULL, 0, &txn));
+			sprintf(sval, "%03x ", values[i]);
+			if (RES(MDB_NOTFOUND, mdb_del(txn, dbi, &key, NULL))) {
+				j--;
+				mdb_txn_abort(txn);
+			} else {
+				E(mdb_txn_commit(txn));
+			}
+	    }
+	    free(values);
+		printf("Deleted %d values\n", j);
+
+		E(mdb_env_stat(env, &mst));
+		E(mdb_txn_begin(env, NULL, 1, &txn));
+		E(mdb_cursor_open(txn, dbi, &cursor));
+		printf("Cursor next\n");
+		while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+			printf("key: %.*s, data: %.*s\n",
+				(int) key.mv_size,  (char *) key.mv_data,
+				(int) data.mv_size, (char *) data.mv_data);
+		}
+		CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+		printf("Cursor last\n");
+		E(mdb_cursor_get(cursor, &key, &data, MDB_LAST));
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+		printf("Cursor prev\n");
+		while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_PREV)) == 0) {
+			printf("key: %.*s, data: %.*s\n",
+				(int) key.mv_size,  (char *) key.mv_data,
+				(int) data.mv_size, (char *) data.mv_data);
+		}
+		CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+		printf("Cursor last/prev\n");
+		E(mdb_cursor_get(cursor, &key, &data, MDB_LAST));
+			printf("key: %.*s, data: %.*s\n",
+				(int) key.mv_size,  (char *) key.mv_data,
+				(int) data.mv_size, (char *) data.mv_data);
+		E(mdb_cursor_get(cursor, &key, &data, MDB_PREV));
+			printf("key: %.*s, data: %.*s\n",
+				(int) key.mv_size,  (char *) key.mv_data,
+				(int) data.mv_size, (char *) data.mv_data);
+
+		mdb_txn_abort(txn);
+
+		printf("Deleting with cursor\n");
+		E(mdb_txn_begin(env, NULL, 0, &txn));
+		E(mdb_cursor_open(txn, dbi, &cur2));
+		for (i=0; i<50; i++) {
+			if (RES(MDB_NOTFOUND, mdb_cursor_get(cur2, &key, &data, MDB_NEXT)))
+				break;
+			printf("key: %p %.*s, data: %p %.*s\n",
+				key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
+				data.mv_data, (int) data.mv_size, (char *) data.mv_data);
+			E(mdb_del(txn, dbi, &key, NULL));
+		}
+
+		printf("Restarting cursor in txn\n");
+		for (op=MDB_FIRST, i=0; i<=32; op=MDB_NEXT, i++) {
+			if (RES(MDB_NOTFOUND, mdb_cursor_get(cur2, &key, &data, op)))
+				break;
+			printf("key: %p %.*s, data: %p %.*s\n",
+				key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
+				data.mv_data, (int) data.mv_size, (char *) data.mv_data);
+		}
+		mdb_cursor_close(cur2);
+		E(mdb_txn_commit(txn));
+
+		printf("Restarting cursor outside txn\n");
+		E(mdb_txn_begin(env, NULL, 0, &txn));
+		E(mdb_cursor_open(txn, dbi, &cursor));
+		for (op=MDB_FIRST, i=0; i<=32; op=MDB_NEXT, i++) {
+			if (RES(MDB_NOTFOUND, mdb_cursor_get(cursor, &key, &data, op)))
+				break;
+			printf("key: %p %.*s, data: %p %.*s\n",
+				key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
+				data.mv_data, (int) data.mv_size, (char *) data.mv_data);
+		}
+		mdb_cursor_close(cursor);
+		mdb_close(env, dbi);
+
+		mdb_txn_abort(txn);
+		mdb_env_close(env);
+
+	return 0;
+}
diff --git a/external/db_drivers/liblmdb/mtest2.c b/external/db_drivers/liblmdb32/mtest2.c
index f1a3dbd6c..f1a3dbd6c 100644
--- a/external/db_drivers/liblmdb/mtest2.c
+++ b/external/db_drivers/liblmdb32/mtest2.c
diff --git a/external/db_drivers/liblmdb/mtest3.c b/external/db_drivers/liblmdb32/mtest3.c
index f705c52de..f705c52de 100644
--- a/external/db_drivers/liblmdb/mtest3.c
+++ b/external/db_drivers/liblmdb32/mtest3.c
diff --git a/external/db_drivers/liblmdb/mtest4.c b/external/db_drivers/liblmdb32/mtest4.c
index da5a95304..da5a95304 100644
--- a/external/db_drivers/liblmdb/mtest4.c
+++ b/external/db_drivers/liblmdb32/mtest4.c
diff --git a/external/db_drivers/liblmdb/mtest5.c b/external/db_drivers/liblmdb32/mtest5.c
index 39a8c728a..39a8c728a 100644
--- a/external/db_drivers/liblmdb/mtest5.c
+++ b/external/db_drivers/liblmdb32/mtest5.c
diff --git a/external/db_drivers/liblmdb/mtest6.c b/external/db_drivers/liblmdb32/mtest6.c
index 07d575893..07d575893 100644
--- a/external/db_drivers/liblmdb/mtest6.c
+++ b/external/db_drivers/liblmdb32/mtest6.c
diff --git a/external/db_drivers/liblmdb/sample-bdb.txt b/external/db_drivers/liblmdb32/sample-bdb.txt
index 6a959bd68..6a959bd68 100644
--- a/external/db_drivers/liblmdb/sample-bdb.txt
+++ b/external/db_drivers/liblmdb32/sample-bdb.txt
diff --git a/external/db_drivers/liblmdb/sample-mdb.txt b/external/db_drivers/liblmdb32/sample-mdb.txt
index a233ec5dd..a233ec5dd 100644
--- a/external/db_drivers/liblmdb/sample-mdb.txt
+++ b/external/db_drivers/liblmdb32/sample-mdb.txt
diff --git a/external/db_drivers/liblmdb/tooltag b/external/db_drivers/liblmdb32/tooltag
index 229bf16ba..229bf16ba 100644
--- a/external/db_drivers/liblmdb/tooltag
+++ b/external/db_drivers/liblmdb32/tooltag
diff --git a/external/db_drivers/liblmdb/.gitignore b/external/db_drivers/liblmdb64/.gitignore
index d5102a87c..d5102a87c 100644
--- a/external/db_drivers/liblmdb/.gitignore
+++ b/external/db_drivers/liblmdb64/.gitignore
diff --git a/external/db_drivers/liblmdb64/CHANGES b/external/db_drivers/liblmdb64/CHANGES
new file mode 100644
index 000000000..34049ba7a
--- /dev/null
+++ b/external/db_drivers/liblmdb64/CHANGES
@@ -0,0 +1,112 @@
+LMDB 0.9 Change Log
+
+LMDB 0.9.14 Release (2014/09/20)
+	Fix to support 64K page size (ITS#7713)
+	Fix to persist decreased as well as increased mapsizes (ITS#7789)
+	Fix cursor bug when deleting last node of a DUPSORT key
+	Fix mdb_env_info to return FIXEDMAP address
+	Fix ambiguous error code from writing to closed DBI (ITS#7825)
+	Fix mdb_copy copying past end of file (ITS#7886)
+	Fix cursor bugs from page_merge/rebalance
+	Fix to dirty fewer pages in deletes (mdb_page_loose())
+	Fix mdb_dbi_open creating subDBs (ITS#7917)
+	Fix mdb_cursor_get(_DUP) with single value (ITS#7913)
+	Fix Windows compat issues in mtests (ITS#7879)
+	Add compacting variant of mdb_copy
+	Add BigEndian integer key compare code
+	Add mdb_dump/mdb_load utilities
+
+LMDB 0.9.13 Release (2014/06/18)
+	Fix mdb_page_alloc unlimited overflow page search
+	Documentation
+		Re-fix MDB_CURRENT doc (ITS#7793)
+		Fix MDB_GET_MULTIPLE/MDB_NEXT_MULTIPLE doc
+
+LMDB 0.9.12 Release (2014/06/13)
+	Fix MDB_GET_BOTH regression (ITS#7875,#7681)
+	Fix MDB_MULTIPLE writing multiple keys (ITS#7834)
+	Fix mdb_rebalance (ITS#7829)
+	Fix mdb_page_split (ITS#7815)
+	Fix md_entries count (ITS#7861,#7828,#7793)
+	Fix MDB_CURRENT (ITS#7793)
+	Fix possible crash on Windows DLL detach
+	Misc code cleanup
+	Documentation
+		mdb_cursor_put: cursor moves on error (ITS#7771)
+
+
+LMDB 0.9.11 Release (2014/01/15)
+	Add mdb_env_set_assert() (ITS#7775)
+	Fix: invalidate txn on page allocation errors (ITS#7377)
+	Fix xcursor tracking in mdb_cursor_del0() (ITS#7771)
+	Fix corruption from deletes (ITS#7756)
+	Fix Windows/MSVC build issues
+	Raise safe limit of max MDB_MAXKEYSIZE
+	Misc code cleanup
+	Documentation
+		Remove spurious note about non-overlapping flags (ITS#7665)
+
+LMDB 0.9.10 Release (2013/11/12)
+	Add MDB_NOMEMINIT option
+	Fix mdb_page_split() again (ITS#7589)
+	Fix MDB_NORDAHEAD definition (ITS#7734)
+	Fix mdb_cursor_del() positioning (ITS#7733)
+	Partial fix for larger page sizes (ITS#7713)
+	Fix Windows64/MSVC build issues
+
+LMDB 0.9.9 Release (2013/10/24)
+	Add mdb_env_get_fd()
+	Add MDB_NORDAHEAD option
+	Add MDB_NOLOCK option
+	Avoid wasting space in mdb_page_split() (ITS#7589)
+	Fix mdb_page_merge() cursor fixup (ITS#7722)
+	Fix mdb_cursor_del() on last delete (ITS#7718)
+	Fix adding WRITEMAP on existing env (ITS#7715)
+	Fix nested txns (ITS#7515)
+	Fix mdb_env_copy() O_DIRECT bug (ITS#7682)
+	Fix mdb_cursor_set(SET_RANGE) return code (ITS#7681)
+	Fix mdb_rebalance() cursor fixup (ITS#7701)
+	Misc code cleanup
+	Documentation
+		Note that by default, readers need write access
+
+
+LMDB 0.9.8 Release (2013/09/09)
+	Allow mdb_env_set_mapsize() on an open environment
+	Fix mdb_dbi_flags() (ITS#7672)
+	Fix mdb_page_unspill() in nested txns
+	Fix mdb_cursor_get(CURRENT|NEXT) after a delete
+	Fix mdb_cursor_get(DUP) to always return key (ITS#7671)
+	Fix mdb_cursor_del() to always advance to next item (ITS#7670)
+	Fix mdb_cursor_set(SET_RANGE) for tree with single page (ITS#7681)
+	Fix mdb_env_copy() retry open if O_DIRECT fails (ITS#7682)
+	Tweak mdb_page_spill() to be less aggressive
+	Documentation
+		Update caveats since mdb_reader_check() added in 0.9.7
+
+LMDB 0.9.7 Release (2013/08/17)
+	Don't leave stale lockfile on failed RDONLY open (ITS#7664)
+	Fix mdb_page_split() ref beyond cursor depth
+	Fix read txn data race (ITS#7635)
+	Fix mdb_rebalance (ITS#7536, #7538)
+	Fix mdb_drop() (ITS#7561)
+	Misc DEBUG macro fixes
+	Add MDB_NOTLS envflag
+	Add mdb_env_copyfd()
+	Add mdb_txn_env() (ITS#7660)
+	Add mdb_dbi_flags() (ITS#7661)
+	Add mdb_env_get_maxkeysize()
+	Add mdb_env_reader_list()/mdb_env_reader_check()
+	Add mdb_page_spill/unspill, remove hard txn size limit
+	Use shorter names for semaphores (ITS#7615)
+	Build
+		Fix install target (ITS#7656)
+	Documentation
+		Misc updates for cursors, DB handles, data lifetime
+
+LMDB 0.9.6 Release (2013/02/25)
+	Many fixes/enhancements
+
+LMDB 0.9.5 Release (2012/11/30)
+	Renamed from libmdb to liblmdb
+	Many fixes/enhancements
diff --git a/cmake/FindLMDB.cmake b/external/db_drivers/liblmdb64/CMakeLists.txt
index b4c90dea2..62b800135 100644
--- a/cmake/FindLMDB.cmake
+++ b/external/db_drivers/liblmdb64/CMakeLists.txt
@@ -1,4 +1,5 @@
-# Copyright (c) 2014, The Monero Project
+# Copyright (c) 2014-2015, The Monero Project
+# 
 # All rights reserved.
 # 
 # Redistribution and use in source and binary forms, with or without modification, are
@@ -25,33 +26,14 @@
 # STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 # THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-MESSAGE(STATUS "Looking for liblmdb")
-
-FIND_PATH(LMDB_INCLUDE_DIR
-  NAMES lmdb.h
-  PATH_SUFFIXES include/ include/lmdb/
-  PATHS "${PROJECT_SOURCE_DIR}"
-  ${LMDB_ROOT}
-  $ENV{LMDB_ROOT}
-  /usr/local/
-  /usr/
-)
+set (lmdb_sources
+mdb.c
+midl.c)
 
-if(STATIC)
-  if(MINGW)
-    find_library(LMDB_LIBRARIES liblmdb.dll.a)
-  else()
-    find_library(LMDB_LIBRARIES liblmdb.a)
-  endif()
-else()
-  find_library(LMDB_LIBRARIES lmdb)
-endif()
+include_directories("${CMAKE_CURRENT_SOURCE_DIR}")
 
-IF(LMDB_INCLUDE_DIR)
-  MESSAGE(STATUS "Found liblmdb include (lmdb.h) in ${LMDB_INCLUDE_DIR}")
-  IF(LMDB_LIBRARIES)
-    MESSAGE(STATUS "Found liblmdb library")
-    set(LMDB_INCLUDE ${LMDB_INCLUDE_DIR})
-    set(LMDB_LIBRARY ${LMDB_LIBRARIES})
-  ENDIF()
-ENDIF()
+add_library(lmdb
+  ${lmdb_sources})
+target_link_libraries(lmdb
+  LINK_PRIVATE
+    ${CMAKE_THREAD_LIBS_INIT})
diff --git a/external/db_drivers/liblmdb64/COPYRIGHT b/external/db_drivers/liblmdb64/COPYRIGHT
new file mode 100644
index 000000000..e0eb484c7
--- /dev/null
+++ b/external/db_drivers/liblmdb64/COPYRIGHT
@@ -0,0 +1,20 @@
+Copyright 2011-2014 Howard Chu, Symas Corp.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted only as authorized by the OpenLDAP
+Public License.
+
+A copy of this license is available in the file LICENSE in the
+top-level directory of the distribution or, alternatively, at
+<http://www.OpenLDAP.org/license.html>.
+
+OpenLDAP is a registered trademark of the OpenLDAP Foundation.
+
+Individual files and/or contributed packages may be copyright by
+other parties and/or subject to additional restrictions.
+
+This work also contains materials derived from public sources.
+
+Additional information about OpenLDAP can be obtained at
+<http://www.openldap.org/>.
diff --git a/external/db_drivers/liblmdb64/Doxyfile b/external/db_drivers/liblmdb64/Doxyfile
new file mode 100644
index 000000000..92d17b09e
--- /dev/null
+++ b/external/db_drivers/liblmdb64/Doxyfile
@@ -0,0 +1,1631 @@
+# Doxyfile 1.7.1
+
+# This file describes the settings to be used by the documentation system
+# doxygen (www.doxygen.org) for a project
+#
+# All text after a hash (#) is considered a comment and will be ignored
+# The format is:
+#       TAG = value [value, ...]
+# For lists items can also be appended using:
+#       TAG += value [value, ...]
+# Values that contain spaces should be placed between quotes (" ")
+
+#---------------------------------------------------------------------------
+# Project related configuration options
+#---------------------------------------------------------------------------
+
+# This tag specifies the encoding used for all characters in the config file
+# that follow. The default is UTF-8 which is also the encoding used for all
+# text before the first occurrence of this tag. Doxygen uses libiconv (or the
+# iconv built into libc) for the transcoding. See
+# http://www.gnu.org/software/libiconv for the list of possible encodings.
+
+DOXYFILE_ENCODING      = UTF-8
+
+# The PROJECT_NAME tag is a single word (or a sequence of words surrounded
+# by quotes) that should identify the project.
+
+PROJECT_NAME           = LMDB
+
+# The PROJECT_NUMBER tag can be used to enter a project or revision number.
+# This could be handy for archiving the generated documentation or
+# if some version control system is used.
+
+PROJECT_NUMBER         =
+
+# The OUTPUT_DIRECTORY tag is used to specify the (relative or absolute)
+# base path where the generated documentation will be put.
+# If a relative path is entered, it will be relative to the location
+# where doxygen was started. If left blank the current directory will be used.
+
+OUTPUT_DIRECTORY       =
+
+# If the CREATE_SUBDIRS tag is set to YES, then doxygen will create
+# 4096 sub-directories (in 2 levels) under the output directory of each output
+# format and will distribute the generated files over these directories.
+# Enabling this option can be useful when feeding doxygen a huge amount of
+# source files, where putting all generated files in the same directory would
+# otherwise cause performance problems for the file system.
+
+CREATE_SUBDIRS         = NO
+
+# The OUTPUT_LANGUAGE tag is used to specify the language in which all
+# documentation generated by doxygen is written. Doxygen will use this
+# information to generate all constant output in the proper language.
+# The default language is English, other supported languages are:
+# Afrikaans, Arabic, Brazilian, Catalan, Chinese, Chinese-Traditional,
+# Croatian, Czech, Danish, Dutch, Esperanto, Farsi, Finnish, French, German,
+# Greek, Hungarian, Italian, Japanese, Japanese-en (Japanese with English
+# messages), Korean, Korean-en, Lithuanian, Norwegian, Macedonian, Persian,
+# Polish, Portuguese, Romanian, Russian, Serbian, Serbian-Cyrilic, Slovak,
+# Slovene, Spanish, Swedish, Ukrainian, and Vietnamese.
+
+OUTPUT_LANGUAGE        = English
+
+# If the BRIEF_MEMBER_DESC tag is set to YES (the default) Doxygen will
+# include brief member descriptions after the members that are listed in
+# the file and class documentation (similar to JavaDoc).
+# Set to NO to disable this.
+
+BRIEF_MEMBER_DESC      = YES
+
+# If the REPEAT_BRIEF tag is set to YES (the default) Doxygen will prepend
+# the brief description of a member or function before the detailed description.
+# Note: if both HIDE_UNDOC_MEMBERS and BRIEF_MEMBER_DESC are set to NO, the
+# brief descriptions will be completely suppressed.
+
+REPEAT_BRIEF           = YES
+
+# This tag implements a quasi-intelligent brief description abbreviator
+# that is used to form the text in various listings. Each string
+# in this list, if found as the leading text of the brief description, will be
+# stripped from the text and the result after processing the whole list, is
+# used as the annotated text. Otherwise, the brief description is used as-is.
+# If left blank, the following values are used ("$name" is automatically
+# replaced with the name of the entity): "The $name class" "The $name widget"
+# "The $name file" "is" "provides" "specifies" "contains"
+# "represents" "a" "an" "the"
+
+ABBREVIATE_BRIEF       =
+
+# If the ALWAYS_DETAILED_SEC and REPEAT_BRIEF tags are both set to YES then
+# Doxygen will generate a detailed section even if there is only a brief
+# description.
+
+ALWAYS_DETAILED_SEC    = NO
+
+# If the INLINE_INHERITED_MEMB tag is set to YES, doxygen will show all
+# inherited members of a class in the documentation of that class as if those
+# members were ordinary class members. Constructors, destructors and assignment
+# operators of the base classes will not be shown.
+
+INLINE_INHERITED_MEMB  = NO
+
+# If the FULL_PATH_NAMES tag is set to YES then Doxygen will prepend the full
+# path before files name in the file list and in the header files. If set
+# to NO the shortest path that makes the file name unique will be used.
+
+FULL_PATH_NAMES        = YES
+
+# If the FULL_PATH_NAMES tag is set to YES then the STRIP_FROM_PATH tag
+# can be used to strip a user-defined part of the path. Stripping is
+# only done if one of the specified strings matches the left-hand part of
+# the path. The tag can be used to show relative paths in the file list.
+# If left blank the directory from which doxygen is run is used as the
+# path to strip.
+
+STRIP_FROM_PATH        =
+
+# The STRIP_FROM_INC_PATH tag can be used to strip a user-defined part of
+# the path mentioned in the documentation of a class, which tells
+# the reader which header file to include in order to use a class.
+# If left blank only the name of the header file containing the class
+# definition is used. Otherwise one should specify the include paths that
+# are normally passed to the compiler using the -I flag.
+
+STRIP_FROM_INC_PATH    =
+
+# If the SHORT_NAMES tag is set to YES, doxygen will generate much shorter
+# (but less readable) file names. This can be useful is your file systems
+# doesn't support long names like on DOS, Mac, or CD-ROM.
+
+SHORT_NAMES            = NO
+
+# If the JAVADOC_AUTOBRIEF tag is set to YES then Doxygen
+# will interpret the first line (until the first dot) of a JavaDoc-style
+# comment as the brief description. If set to NO, the JavaDoc
+# comments will behave just like regular Qt-style comments
+# (thus requiring an explicit @brief command for a brief description.)
+
+JAVADOC_AUTOBRIEF      = NO
+
+# If the QT_AUTOBRIEF tag is set to YES then Doxygen will
+# interpret the first line (until the first dot) of a Qt-style
+# comment as the brief description. If set to NO, the comments
+# will behave just like regular Qt-style comments (thus requiring
+# an explicit \brief command for a brief description.)
+
+QT_AUTOBRIEF           = NO
+
+# The MULTILINE_CPP_IS_BRIEF tag can be set to YES to make Doxygen
+# treat a multi-line C++ special comment block (i.e. a block of //! or ///
+# comments) as a brief description. This used to be the default behaviour.
+# The new default is to treat a multi-line C++ comment block as a detailed
+# description. Set this tag to YES if you prefer the old behaviour instead.
+
+MULTILINE_CPP_IS_BRIEF = NO
+
+# If the INHERIT_DOCS tag is set to YES (the default) then an undocumented
+# member inherits the documentation from any documented member that it
+# re-implements.
+
+INHERIT_DOCS           = YES
+
+# If the SEPARATE_MEMBER_PAGES tag is set to YES, then doxygen will produce
+# a new page for each member. If set to NO, the documentation of a member will
+# be part of the file/class/namespace that contains it.
+
+SEPARATE_MEMBER_PAGES  = NO
+
+# The TAB_SIZE tag can be used to set the number of spaces in a tab.
+# Doxygen uses this value to replace tabs by spaces in code fragments.
+
+TAB_SIZE               = 4
+
+# This tag can be used to specify a number of aliases that acts
+# as commands in the documentation. An alias has the form "name=value".
+# For example adding "sideeffect=\par Side Effects:\n" will allow you to
+# put the command \sideeffect (or @sideeffect) in the documentation, which
+# will result in a user-defined paragraph with heading "Side Effects:".
+# You can put \n's in the value part of an alias to insert newlines.
+
+ALIASES                =
+
+# Set the OPTIMIZE_OUTPUT_FOR_C tag to YES if your project consists of C
+# sources only. Doxygen will then generate output that is more tailored for C.
+# For instance, some of the names that are used will be different. The list
+# of all members will be omitted, etc.
+
+OPTIMIZE_OUTPUT_FOR_C  = YES
+
+# Set the OPTIMIZE_OUTPUT_JAVA tag to YES if your project consists of Java
+# sources only. Doxygen will then generate output that is more tailored for
+# Java. For instance, namespaces will be presented as packages, qualified
+# scopes will look different, etc.
+
+OPTIMIZE_OUTPUT_JAVA   = NO
+
+# Set the OPTIMIZE_FOR_FORTRAN tag to YES if your project consists of Fortran
+# sources only. Doxygen will then generate output that is more tailored for
+# Fortran.
+
+OPTIMIZE_FOR_FORTRAN   = NO
+
+# Set the OPTIMIZE_OUTPUT_VHDL tag to YES if your project consists of VHDL
+# sources. Doxygen will then generate output that is tailored for
+# VHDL.
+
+OPTIMIZE_OUTPUT_VHDL   = NO
+
+# Doxygen selects the parser to use depending on the extension of the files it
+# parses. With this tag you can assign which parser to use for a given extension.
+# Doxygen has a built-in mapping, but you can override or extend it using this
+# tag. The format is ext=language, where ext is a file extension, and language
+# is one of the parsers supported by doxygen: IDL, Java, Javascript, CSharp, C,
+# C++, D, PHP, Objective-C, Python, Fortran, VHDL, C, C++. For instance to make
+# doxygen treat .inc files as Fortran files (default is PHP), and .f files as C
+# (default is Fortran), use: inc=Fortran f=C. Note that for custom extensions
+# you also need to set FILE_PATTERNS otherwise the files are not read by doxygen.
+
+EXTENSION_MAPPING      =
+
+# If you use STL classes (i.e. std::string, std::vector, etc.) but do not want
+# to include (a tag file for) the STL sources as input, then you should
+# set this tag to YES in order to let doxygen match functions declarations and
+# definitions whose arguments contain STL classes (e.g. func(std::string); v.s.
+# func(std::string) {}). This also make the inheritance and collaboration
+# diagrams that involve STL classes more complete and accurate.
+
+BUILTIN_STL_SUPPORT    = NO
+
+# If you use Microsoft's C++/CLI language, you should set this option to YES to
+# enable parsing support.
+
+CPP_CLI_SUPPORT        = NO
+
+# Set the SIP_SUPPORT tag to YES if your project consists of sip sources only.
+# Doxygen will parse them like normal C++ but will assume all classes use public
+# instead of private inheritance when no explicit protection keyword is present.
+
+SIP_SUPPORT            = NO
+
+# For Microsoft's IDL there are propget and propput attributes to indicate getter
+# and setter methods for a property. Setting this option to YES (the default)
+# will make doxygen to replace the get and set methods by a property in the
+# documentation. This will only work if the methods are indeed getting or
+# setting a simple type. If this is not the case, or you want to show the
+# methods anyway, you should set this option to NO.
+
+IDL_PROPERTY_SUPPORT   = YES
+
+# If member grouping is used in the documentation and the DISTRIBUTE_GROUP_DOC
+# tag is set to YES, then doxygen will reuse the documentation of the first
+# member in the group (if any) for the other members of the group. By default
+# all members of a group must be documented explicitly.
+
+DISTRIBUTE_GROUP_DOC   = NO
+
+# Set the SUBGROUPING tag to YES (the default) to allow class member groups of
+# the same type (for instance a group of public functions) to be put as a
+# subgroup of that type (e.g. under the Public Functions section). Set it to
+# NO to prevent subgrouping. Alternatively, this can be done per class using
+# the \nosubgrouping command.
+
+SUBGROUPING            = YES
+
+INLINE_GROUPED_CLASSES = YES
+# When TYPEDEF_HIDES_STRUCT is enabled, a typedef of a struct, union, or enum
+# is documented as struct, union, or enum with the name of the typedef. So
+# typedef struct TypeS {} TypeT, will appear in the documentation as a struct
+# with name TypeT. When disabled the typedef will appear as a member of a file,
+# namespace, or class. And the struct will be named TypeS. This can typically
+# be useful for C code in case the coding convention dictates that all compound
+# types are typedef'ed and only the typedef is referenced, never the tag name.
+
+TYPEDEF_HIDES_STRUCT   = YES
+
+# The SYMBOL_CACHE_SIZE determines the size of the internal cache use to
+# determine which symbols to keep in memory and which to flush to disk.
+# When the cache is full, less often used symbols will be written to disk.
+# For small to medium size projects (<1000 input files) the default value is
+# probably good enough. For larger projects a too small cache size can cause
+# doxygen to be busy swapping symbols to and from disk most of the time
+# causing a significant performance penality.
+# If the system has enough physical memory increasing the cache will improve the
+# performance by keeping more symbols in memory. Note that the value works on
+# a logarithmic scale so increasing the size by one will rougly double the
+# memory usage. The cache size is given by this formula:
+# 2^(16+SYMBOL_CACHE_SIZE). The valid range is 0..9, the default is 0,
+# corresponding to a cache size of 2^16 = 65536 symbols
+
+SYMBOL_CACHE_SIZE      = 0
+
+#---------------------------------------------------------------------------
+# Build related configuration options
+#---------------------------------------------------------------------------
+
+# If the EXTRACT_ALL tag is set to YES doxygen will assume all entities in
+# documentation are documented, even if no documentation was available.
+# Private class members and static file members will be hidden unless
+# the EXTRACT_PRIVATE and EXTRACT_STATIC tags are set to YES
+
+EXTRACT_ALL            = NO
+
+# If the EXTRACT_PRIVATE tag is set to YES all private members of a class
+# will be included in the documentation.
+
+EXTRACT_PRIVATE        = NO
+
+# If the EXTRACT_STATIC tag is set to YES all static members of a file
+# will be included in the documentation.
+
+EXTRACT_STATIC         = YES
+
+# If the EXTRACT_LOCAL_CLASSES tag is set to YES classes (and structs)
+# defined locally in source files will be included in the documentation.
+# If set to NO only classes defined in header files are included.
+
+EXTRACT_LOCAL_CLASSES  = YES
+
+# This flag is only useful for Objective-C code. When set to YES local
+# methods, which are defined in the implementation section but not in
+# the interface are included in the documentation.
+# If set to NO (the default) only methods in the interface are included.
+
+EXTRACT_LOCAL_METHODS  = NO
+
+# If this flag is set to YES, the members of anonymous namespaces will be
+# extracted and appear in the documentation as a namespace called
+# 'anonymous_namespace{file}', where file will be replaced with the base
+# name of the file that contains the anonymous namespace. By default
+# anonymous namespace are hidden.
+
+EXTRACT_ANON_NSPACES   = NO
+
+# If the HIDE_UNDOC_MEMBERS tag is set to YES, Doxygen will hide all
+# undocumented members of documented classes, files or namespaces.
+# If set to NO (the default) these members will be included in the
+# various overviews, but no documentation section is generated.
+# This option has no effect if EXTRACT_ALL is enabled.
+
+HIDE_UNDOC_MEMBERS     = NO
+
+# If the HIDE_UNDOC_CLASSES tag is set to YES, Doxygen will hide all
+# undocumented classes that are normally visible in the class hierarchy.
+# If set to NO (the default) these classes will be included in the various
+# overviews. This option has no effect if EXTRACT_ALL is enabled.
+
+HIDE_UNDOC_CLASSES     = NO
+
+# If the HIDE_FRIEND_COMPOUNDS tag is set to YES, Doxygen will hide all
+# friend (class|struct|union) declarations.
+# If set to NO (the default) these declarations will be included in the
+# documentation.
+
+HIDE_FRIEND_COMPOUNDS  = NO
+
+# If the HIDE_IN_BODY_DOCS tag is set to YES, Doxygen will hide any
+# documentation blocks found inside the body of a function.
+# If set to NO (the default) these blocks will be appended to the
+# function's detailed documentation block.
+
+HIDE_IN_BODY_DOCS      = NO
+
+# The INTERNAL_DOCS tag determines if documentation
+# that is typed after a \internal command is included. If the tag is set
+# to NO (the default) then the documentation will be excluded.
+# Set it to YES to include the internal documentation.
+
+INTERNAL_DOCS          = NO
+
+# If the CASE_SENSE_NAMES tag is set to NO then Doxygen will only generate
+# file names in lower-case letters. If set to YES upper-case letters are also
+# allowed. This is useful if you have classes or files whose names only differ
+# in case and if your file system supports case sensitive file names. Windows
+# and Mac users are advised to set this option to NO.
+
+CASE_SENSE_NAMES       = YES
+
+# If the HIDE_SCOPE_NAMES tag is set to NO (the default) then Doxygen
+# will show members with their full class and namespace scopes in the
+# documentation. If set to YES the scope will be hidden.
+
+HIDE_SCOPE_NAMES       = NO
+
+# If the SHOW_INCLUDE_FILES tag is set to YES (the default) then Doxygen
+# will put a list of the files that are included by a file in the documentation
+# of that file.
+
+SHOW_INCLUDE_FILES     = YES
+
+# If the FORCE_LOCAL_INCLUDES tag is set to YES then Doxygen
+# will list include files with double quotes in the documentation
+# rather than with sharp brackets.
+
+FORCE_LOCAL_INCLUDES   = NO
+
+# If the INLINE_INFO tag is set to YES (the default) then a tag [inline]
+# is inserted in the documentation for inline members.
+
+INLINE_INFO            = YES
+
+# If the SORT_MEMBER_DOCS tag is set to YES (the default) then doxygen
+# will sort the (detailed) documentation of file and class members
+# alphabetically by member name. If set to NO the members will appear in
+# declaration order.
+
+SORT_MEMBER_DOCS       = NO
+
+# If the SORT_BRIEF_DOCS tag is set to YES then doxygen will sort the
+# brief documentation of file, namespace and class members alphabetically
+# by member name. If set to NO (the default) the members will appear in
+# declaration order.
+
+SORT_BRIEF_DOCS        = NO
+
+# If the SORT_MEMBERS_CTORS_1ST tag is set to YES then doxygen
+# will sort the (brief and detailed) documentation of class members so that
+# constructors and destructors are listed first. If set to NO (the default)
+# the constructors will appear in the respective orders defined by
+# SORT_MEMBER_DOCS and SORT_BRIEF_DOCS.
+# This tag will be ignored for brief docs if SORT_BRIEF_DOCS is set to NO
+# and ignored for detailed docs if SORT_MEMBER_DOCS is set to NO.
+
+SORT_MEMBERS_CTORS_1ST = NO
+
+# If the SORT_GROUP_NAMES tag is set to YES then doxygen will sort the
+# hierarchy of group names into alphabetical order. If set to NO (the default)
+# the group names will appear in their defined order.
+
+SORT_GROUP_NAMES       = NO
+
+# If the SORT_BY_SCOPE_NAME tag is set to YES, the class list will be
+# sorted by fully-qualified names, including namespaces. If set to
+# NO (the default), the class list will be sorted only by class name,
+# not including the namespace part.
+# Note: This option is not very useful if HIDE_SCOPE_NAMES is set to YES.
+# Note: This option applies only to the class list, not to the
+# alphabetical list.
+
+SORT_BY_SCOPE_NAME     = NO
+
+# The GENERATE_TODOLIST tag can be used to enable (YES) or
+# disable (NO) the todo list. This list is created by putting \todo
+# commands in the documentation.
+
+GENERATE_TODOLIST      = YES
+
+# The GENERATE_TESTLIST tag can be used to enable (YES) or
+# disable (NO) the test list. This list is created by putting \test
+# commands in the documentation.
+
+GENERATE_TESTLIST      = YES
+
+# The GENERATE_BUGLIST tag can be used to enable (YES) or
+# disable (NO) the bug list. This list is created by putting \bug
+# commands in the documentation.
+
+GENERATE_BUGLIST       = YES
+
+# The GENERATE_DEPRECATEDLIST tag can be used to enable (YES) or
+# disable (NO) the deprecated list. This list is created by putting
+# \deprecated commands in the documentation.
+
+GENERATE_DEPRECATEDLIST= YES
+
+# The ENABLED_SECTIONS tag can be used to enable conditional
+# documentation sections, marked by \if sectionname ... \endif.
+
+ENABLED_SECTIONS       =
+
+# The MAX_INITIALIZER_LINES tag determines the maximum number of lines
+# the initial value of a variable or define consists of for it to appear in
+# the documentation. If the initializer consists of more lines than specified
+# here it will be hidden. Use a value of 0 to hide initializers completely.
+# The appearance of the initializer of individual variables and defines in the
+# documentation can be controlled using \showinitializer or \hideinitializer
+# command in the documentation regardless of this setting.
+
+MAX_INITIALIZER_LINES  = 30
+
+# Set the SHOW_USED_FILES tag to NO to disable the list of files generated
+# at the bottom of the documentation of classes and structs. If set to YES the
+# list will mention the files that were used to generate the documentation.
+
+SHOW_USED_FILES        = YES
+
+# If the sources in your project are distributed over multiple directories
+# then setting the SHOW_DIRECTORIES tag to YES will show the directory hierarchy
+# in the documentation. The default is NO.
+
+SHOW_DIRECTORIES       = NO
+
+# Set the SHOW_FILES tag to NO to disable the generation of the Files page.
+# This will remove the Files entry from the Quick Index and from the
+# Folder Tree View (if specified). The default is YES.
+
+SHOW_FILES             = YES
+
+# Set the SHOW_NAMESPACES tag to NO to disable the generation of the
+# Namespaces page.
+# This will remove the Namespaces entry from the Quick Index
+# and from the Folder Tree View (if specified). The default is YES.
+
+SHOW_NAMESPACES        = YES
+
+# The FILE_VERSION_FILTER tag can be used to specify a program or script that
+# doxygen should invoke to get the current version for each file (typically from
+# the version control system). Doxygen will invoke the program by executing (via
+# popen()) the command <command> <input-file>, where <command> is the value of
+# the FILE_VERSION_FILTER tag, and <input-file> is the name of an input file
+# provided by doxygen. Whatever the program writes to standard output
+# is used as the file version. See the manual for examples.
+
+FILE_VERSION_FILTER    =
+
+# The LAYOUT_FILE tag can be used to specify a layout file which will be parsed
+# by doxygen. The layout file controls the global structure of the generated
+# output files in an output format independent way. The create the layout file
+# that represents doxygen's defaults, run doxygen with the -l option.
+# You can optionally specify a file name after the option, if omitted
+# DoxygenLayout.xml will be used as the name of the layout file.
+
+LAYOUT_FILE            =
+
+#---------------------------------------------------------------------------
+# configuration options related to warning and progress messages
+#---------------------------------------------------------------------------
+
+# The QUIET tag can be used to turn on/off the messages that are generated
+# by doxygen. Possible values are YES and NO. If left blank NO is used.
+
+QUIET                  = NO
+
+# The WARNINGS tag can be used to turn on/off the warning messages that are
+# generated by doxygen. Possible values are YES and NO. If left blank
+# NO is used.
+
+WARNINGS               = YES
+
+# If WARN_IF_UNDOCUMENTED is set to YES, then doxygen will generate warnings
+# for undocumented members. If EXTRACT_ALL is set to YES then this flag will
+# automatically be disabled.
+
+WARN_IF_UNDOCUMENTED   = YES
+
+# If WARN_IF_DOC_ERROR is set to YES, doxygen will generate warnings for
+# potential errors in the documentation, such as not documenting some
+# parameters in a documented function, or documenting parameters that
+# don't exist or using markup commands wrongly.
+
+WARN_IF_DOC_ERROR      = YES
+
+# This WARN_NO_PARAMDOC option can be abled to get warnings for
+# functions that are documented, but have no documentation for their parameters
+# or return value. If set to NO (the default) doxygen will only warn about
+# wrong or incomplete parameter documentation, but not about the absence of
+# documentation.
+
+WARN_NO_PARAMDOC       = NO
+
+# The WARN_FORMAT tag determines the format of the warning messages that
+# doxygen can produce. The string should contain the $file, $line, and $text
+# tags, which will be replaced by the file and line number from which the
+# warning originated and the warning text. Optionally the format may contain
+# $version, which will be replaced by the version of the file (if it could
+# be obtained via FILE_VERSION_FILTER)
+
+WARN_FORMAT            = "$file:$line: $text"
+
+# The WARN_LOGFILE tag can be used to specify a file to which warning
+# and error messages should be written. If left blank the output is written
+# to stderr.
+
+WARN_LOGFILE           =
+
+#---------------------------------------------------------------------------
+# configuration options related to the input files
+#---------------------------------------------------------------------------
+
+# The INPUT tag can be used to specify the files and/or directories that contain
+# documented source files. You may enter file names like "myfile.cpp" or
+# directories like "/usr/src/myproject". Separate the files or directories
+# with spaces.
+
+INPUT                  = lmdb.h midl.h mdb.c midl.c
+
+# This tag can be used to specify the character encoding of the source files
+# that doxygen parses. Internally doxygen uses the UTF-8 encoding, which is
+# also the default input encoding. Doxygen uses libiconv (or the iconv built
+# into libc) for the transcoding. See http://www.gnu.org/software/libiconv for
+# the list of possible encodings.
+
+INPUT_ENCODING         = UTF-8
+
+# If the value of the INPUT tag contains directories, you can use the
+# FILE_PATTERNS tag to specify one or more wildcard pattern (like *.cpp
+# and *.h) to filter out the source-files in the directories. If left
+# blank the following patterns are tested:
+# *.c *.cc *.cxx *.cpp *.c++ *.java *.ii *.ixx *.ipp *.i++ *.inl *.h *.hh *.hxx
+# *.hpp *.h++ *.idl *.odl *.cs *.php *.php3 *.inc *.m *.mm *.py *.f90
+
+FILE_PATTERNS          =
+
+# The RECURSIVE tag can be used to turn specify whether or not subdirectories
+# should be searched for input files as well. Possible values are YES and NO.
+# If left blank NO is used.
+
+RECURSIVE              = NO
+
+# The EXCLUDE tag can be used to specify files and/or directories that should
+# excluded from the INPUT source files. This way you can easily exclude a
+# subdirectory from a directory tree whose root is specified with the INPUT tag.
+
+EXCLUDE                =
+
+# The EXCLUDE_SYMLINKS tag can be used select whether or not files or
+# directories that are symbolic links (a Unix filesystem feature) are excluded
+# from the input.
+
+EXCLUDE_SYMLINKS       = NO
+
+# If the value of the INPUT tag contains directories, you can use the
+# EXCLUDE_PATTERNS tag to specify one or more wildcard patterns to exclude
+# certain files from those directories. Note that the wildcards are matched
+# against the file with absolute path, so to exclude all test directories
+# for example use the pattern */test/*
+
+EXCLUDE_PATTERNS       =
+
+# The EXCLUDE_SYMBOLS tag can be used to specify one or more symbol names
+# (namespaces, classes, functions, etc.) that should be excluded from the
+# output. The symbol name can be a fully qualified name, a word, or if the
+# wildcard * is used, a substring. Examples: ANamespace, AClass,
+# AClass::ANamespace, ANamespace::*Test
+
+EXCLUDE_SYMBOLS        =
+
+# The EXAMPLE_PATH tag can be used to specify one or more files or
+# directories that contain example code fragments that are included (see
+# the \include command).
+
+EXAMPLE_PATH           =
+
+# If the value of the EXAMPLE_PATH tag contains directories, you can use the
+# EXAMPLE_PATTERNS tag to specify one or more wildcard pattern (like *.cpp
+# and *.h) to filter out the source-files in the directories. If left
+# blank all files are included.
+
+EXAMPLE_PATTERNS       =
+
+# If the EXAMPLE_RECURSIVE tag is set to YES then subdirectories will be
+# searched for input files to be used with the \include or \dontinclude
+# commands irrespective of the value of the RECURSIVE tag.
+# Possible values are YES and NO. If left blank NO is used.
+
+EXAMPLE_RECURSIVE      = NO
+
+# The IMAGE_PATH tag can be used to specify one or more files or
+# directories that contain image that are included in the documentation (see
+# the \image command).
+
+IMAGE_PATH             =
+
+# The INPUT_FILTER tag can be used to specify a program that doxygen should
+# invoke to filter for each input file. Doxygen will invoke the filter program
+# by executing (via popen()) the command <filter> <input-file>, where <filter>
+# is the value of the INPUT_FILTER tag, and <input-file> is the name of an
+# input file. Doxygen will then use the output that the filter program writes
+# to standard output.
+# If FILTER_PATTERNS is specified, this tag will be
+# ignored.
+
+INPUT_FILTER           =
+
+# The FILTER_PATTERNS tag can be used to specify filters on a per file pattern
+# basis.
+# Doxygen will compare the file name with each pattern and apply the
+# filter if there is a match.
+# The filters are a list of the form:
+# pattern=filter (like *.cpp=my_cpp_filter). See INPUT_FILTER for further
+# info on how filters are used. If FILTER_PATTERNS is empty, INPUT_FILTER
+# is applied to all files.
+
+FILTER_PATTERNS        =
+
+# If the FILTER_SOURCE_FILES tag is set to YES, the input filter (if set using
+# INPUT_FILTER) will be used to filter the input files when producing source
+# files to browse (i.e. when SOURCE_BROWSER is set to YES).
+
+FILTER_SOURCE_FILES    = NO
+
+#---------------------------------------------------------------------------
+# configuration options related to source browsing
+#---------------------------------------------------------------------------
+
+# If the SOURCE_BROWSER tag is set to YES then a list of source files will
+# be generated. Documented entities will be cross-referenced with these sources.
+# Note: To get rid of all source code in the generated output, make sure also
+# VERBATIM_HEADERS is set to NO.
+
+SOURCE_BROWSER         = NO
+
+# Setting the INLINE_SOURCES tag to YES will include the body
+# of functions and classes directly in the documentation.
+
+INLINE_SOURCES         = NO
+
+# Setting the STRIP_CODE_COMMENTS tag to YES (the default) will instruct
+# doxygen to hide any special comment blocks from generated source code
+# fragments. Normal C and C++ comments will always remain visible.
+
+STRIP_CODE_COMMENTS    = YES
+
+# If the REFERENCED_BY_RELATION tag is set to YES
+# then for each documented function all documented
+# functions referencing it will be listed.
+
+REFERENCED_BY_RELATION = NO
+
+# If the REFERENCES_RELATION tag is set to YES
+# then for each documented function all documented entities
+# called/used by that function will be listed.
+
+REFERENCES_RELATION    = NO
+
+# If the REFERENCES_LINK_SOURCE tag is set to YES (the default)
+# and SOURCE_BROWSER tag is set to YES, then the hyperlinks from
+# functions in REFERENCES_RELATION and REFERENCED_BY_RELATION lists will
+# link to the source code.
+# Otherwise they will link to the documentation.
+
+REFERENCES_LINK_SOURCE = YES
+
+# If the USE_HTAGS tag is set to YES then the references to source code
+# will point to the HTML generated by the htags(1) tool instead of doxygen
+# built-in source browser. The htags tool is part of GNU's global source
+# tagging system (see http://www.gnu.org/software/global/global.html). You
+# will need version 4.8.6 or higher.
+
+USE_HTAGS              = NO
+
+# If the VERBATIM_HEADERS tag is set to YES (the default) then Doxygen
+# will generate a verbatim copy of the header file for each class for
+# which an include is specified. Set to NO to disable this.
+
+VERBATIM_HEADERS       = YES
+
+#---------------------------------------------------------------------------
+# configuration options related to the alphabetical class index
+#---------------------------------------------------------------------------
+
+# If the ALPHABETICAL_INDEX tag is set to YES, an alphabetical index
+# of all compounds will be generated. Enable this if the project
+# contains a lot of classes, structs, unions or interfaces.
+
+ALPHABETICAL_INDEX     = YES
+
+# If the alphabetical index is enabled (see ALPHABETICAL_INDEX) then
+# the COLS_IN_ALPHA_INDEX tag can be used to specify the number of columns
+# in which this list will be split (can be a number in the range [1..20])
+
+COLS_IN_ALPHA_INDEX    = 5
+
+# In case all classes in a project start with a common prefix, all
+# classes will be put under the same header in the alphabetical index.
+# The IGNORE_PREFIX tag can be used to specify one or more prefixes that
+# should be ignored while generating the index headers.
+
+IGNORE_PREFIX          =
+
+#---------------------------------------------------------------------------
+# configuration options related to the HTML output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_HTML tag is set to YES (the default) Doxygen will
+# generate HTML output.
+
+GENERATE_HTML          = YES
+
+# The HTML_OUTPUT tag is used to specify where the HTML docs will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be
+# put in front of it. If left blank `html' will be used as the default path.
+
+HTML_OUTPUT            = html
+
+# The HTML_FILE_EXTENSION tag can be used to specify the file extension for
+# each generated HTML page (for example: .htm,.php,.asp). If it is left blank
+# doxygen will generate files with .html extension.
+
+HTML_FILE_EXTENSION    = .html
+
+# The HTML_HEADER tag can be used to specify a personal HTML header for
+# each generated HTML page. If it is left blank doxygen will generate a
+# standard header.
+
+HTML_HEADER            =
+
+# The HTML_FOOTER tag can be used to specify a personal HTML footer for
+# each generated HTML page. If it is left blank doxygen will generate a
+# standard footer.
+
+HTML_FOOTER            =
+
+# The HTML_STYLESHEET tag can be used to specify a user-defined cascading
+# style sheet that is used by each HTML page. It can be used to
+# fine-tune the look of the HTML output. If the tag is left blank doxygen
+# will generate a default style sheet. Note that doxygen will try to copy
+# the style sheet file to the HTML output directory, so don't put your own
+# stylesheet in the HTML output directory as well, or it will be erased!
+
+HTML_STYLESHEET        =
+
+# The HTML_COLORSTYLE_HUE tag controls the color of the HTML output.
+# Doxygen will adjust the colors in the stylesheet and background images
+# according to this color. Hue is specified as an angle on a colorwheel,
+# see http://en.wikipedia.org/wiki/Hue for more information.
+# For instance the value 0 represents red, 60 is yellow, 120 is green,
+# 180 is cyan, 240 is blue, 300 purple, and 360 is red again.
+# The allowed range is 0 to 359.
+
+HTML_COLORSTYLE_HUE    = 220
+
+# The HTML_COLORSTYLE_SAT tag controls the purity (or saturation) of
+# the colors in the HTML output. For a value of 0 the output will use
+# grayscales only. A value of 255 will produce the most vivid colors.
+
+HTML_COLORSTYLE_SAT    = 100
+
+# The HTML_COLORSTYLE_GAMMA tag controls the gamma correction applied to
+# the luminance component of the colors in the HTML output. Values below
+# 100 gradually make the output lighter, whereas values above 100 make
+# the output darker. The value divided by 100 is the actual gamma applied,
+# so 80 represents a gamma of 0.8, The value 220 represents a gamma of 2.2,
+# and 100 does not change the gamma.
+
+HTML_COLORSTYLE_GAMMA  = 80
+
+# If the HTML_TIMESTAMP tag is set to YES then the footer of each generated HTML
+# page will contain the date and time when the page was generated. Setting
+# this to NO can help when comparing the output of multiple runs.
+
+HTML_TIMESTAMP         = YES
+
+# If the HTML_ALIGN_MEMBERS tag is set to YES, the members of classes,
+# files or namespaces will be aligned in HTML using tables. If set to
+# NO a bullet list will be used.
+
+HTML_ALIGN_MEMBERS     = YES
+
+# If the HTML_DYNAMIC_SECTIONS tag is set to YES then the generated HTML
+# documentation will contain sections that can be hidden and shown after the
+# page has loaded. For this to work a browser that supports
+# JavaScript and DHTML is required (for instance Mozilla 1.0+, Firefox
+# Netscape 6.0+, Internet explorer 5.0+, Konqueror, or Safari).
+
+HTML_DYNAMIC_SECTIONS  = NO
+
+# If the GENERATE_DOCSET tag is set to YES, additional index files
+# will be generated that can be used as input for Apple's Xcode 3
+# integrated development environment, introduced with OSX 10.5 (Leopard).
+# To create a documentation set, doxygen will generate a Makefile in the
+# HTML output directory. Running make will produce the docset in that
+# directory and running "make install" will install the docset in
+# ~/Library/Developer/Shared/Documentation/DocSets so that Xcode will find
+# it at startup.
+# See http://developer.apple.com/tools/creatingdocsetswithdoxygen.html
+# for more information.
+
+GENERATE_DOCSET        = NO
+
+# When GENERATE_DOCSET tag is set to YES, this tag determines the name of the
+# feed. A documentation feed provides an umbrella under which multiple
+# documentation sets from a single provider (such as a company or product suite)
+# can be grouped.
+
+DOCSET_FEEDNAME        = "Doxygen generated docs"
+
+# When GENERATE_DOCSET tag is set to YES, this tag specifies a string that
+# should uniquely identify the documentation set bundle. This should be a
+# reverse domain-name style string, e.g. com.mycompany.MyDocSet. Doxygen
+# will append .docset to the name.
+
+DOCSET_BUNDLE_ID       = org.doxygen.Project
+
+# When GENERATE_PUBLISHER_ID tag specifies a string that should uniquely identify
+# the documentation publisher. This should be a reverse domain-name style
+# string, e.g. com.mycompany.MyDocSet.documentation.
+
+DOCSET_PUBLISHER_ID    = org.doxygen.Publisher
+
+# The GENERATE_PUBLISHER_NAME tag identifies the documentation publisher.
+
+DOCSET_PUBLISHER_NAME  = Publisher
+
+# If the GENERATE_HTMLHELP tag is set to YES, additional index files
+# will be generated that can be used as input for tools like the
+# Microsoft HTML help workshop to generate a compiled HTML help file (.chm)
+# of the generated HTML documentation.
+
+GENERATE_HTMLHELP      = NO
+
+# If the GENERATE_HTMLHELP tag is set to YES, the CHM_FILE tag can
+# be used to specify the file name of the resulting .chm file. You
+# can add a path in front of the file if the result should not be
+# written to the html output directory.
+
+CHM_FILE               =
+
+# If the GENERATE_HTMLHELP tag is set to YES, the HHC_LOCATION tag can
+# be used to specify the location (absolute path including file name) of
+# the HTML help compiler (hhc.exe). If non-empty doxygen will try to run
+# the HTML help compiler on the generated index.hhp.
+
+HHC_LOCATION           =
+
+# If the GENERATE_HTMLHELP tag is set to YES, the GENERATE_CHI flag
+# controls if a separate .chi index file is generated (YES) or that
+# it should be included in the master .chm file (NO).
+
+GENERATE_CHI           = NO
+
+# If the GENERATE_HTMLHELP tag is set to YES, the CHM_INDEX_ENCODING
+# is used to encode HtmlHelp index (hhk), content (hhc) and project file
+# content.
+
+CHM_INDEX_ENCODING     =
+
+# If the GENERATE_HTMLHELP tag is set to YES, the BINARY_TOC flag
+# controls whether a binary table of contents is generated (YES) or a
+# normal table of contents (NO) in the .chm file.
+
+BINARY_TOC             = NO
+
+# The TOC_EXPAND flag can be set to YES to add extra items for group members
+# to the contents of the HTML help documentation and to the tree view.
+
+TOC_EXPAND             = NO
+
+# If the GENERATE_QHP tag is set to YES and both QHP_NAMESPACE and
+# QHP_VIRTUAL_FOLDER are set, an additional index file will be generated
+# that can be used as input for Qt's qhelpgenerator to generate a
+# Qt Compressed Help (.qch) of the generated HTML documentation.
+
+GENERATE_QHP           = NO
+
+# If the QHG_LOCATION tag is specified, the QCH_FILE tag can
+# be used to specify the file name of the resulting .qch file.
+# The path specified is relative to the HTML output folder.
+
+QCH_FILE               =
+
+# The QHP_NAMESPACE tag specifies the namespace to use when generating
+# Qt Help Project output. For more information please see
+# http://doc.trolltech.com/qthelpproject.html#namespace
+
+QHP_NAMESPACE          = org.doxygen.Project
+
+# The QHP_VIRTUAL_FOLDER tag specifies the namespace to use when generating
+# Qt Help Project output. For more information please see
+# http://doc.trolltech.com/qthelpproject.html#virtual-folders
+
+QHP_VIRTUAL_FOLDER     = doc
+
+# If QHP_CUST_FILTER_NAME is set, it specifies the name of a custom filter to
+# add. For more information please see
+# http://doc.trolltech.com/qthelpproject.html#custom-filters
+
+QHP_CUST_FILTER_NAME   =
+
+# The QHP_CUST_FILT_ATTRS tag specifies the list of the attributes of the
+# custom filter to add. For more information please see
+# <a href="http://doc.trolltech.com/qthelpproject.html#custom-filters">
+# Qt Help Project / Custom Filters</a>.
+
+QHP_CUST_FILTER_ATTRS  =
+
+# The QHP_SECT_FILTER_ATTRS tag specifies the list of the attributes this
+# project's
+# filter section matches.
+# <a href="http://doc.trolltech.com/qthelpproject.html#filter-attributes">
+# Qt Help Project / Filter Attributes</a>.
+
+QHP_SECT_FILTER_ATTRS  =
+
+# If the GENERATE_QHP tag is set to YES, the QHG_LOCATION tag can
+# be used to specify the location of Qt's qhelpgenerator.
+# If non-empty doxygen will try to run qhelpgenerator on the generated
+# .qhp file.
+
+QHG_LOCATION           =
+
+# If the GENERATE_ECLIPSEHELP tag is set to YES, additional index files
+#  will be generated, which together with the HTML files, form an Eclipse help
+# plugin. To install this plugin and make it available under the help contents
+# menu in Eclipse, the contents of the directory containing the HTML and XML
+# files needs to be copied into the plugins directory of eclipse. The name of
+# the directory within the plugins directory should be the same as
+# the ECLIPSE_DOC_ID value. After copying Eclipse needs to be restarted before
+# the help appears.
+
+GENERATE_ECLIPSEHELP   = NO
+
+# A unique identifier for the eclipse help plugin. When installing the plugin
+# the directory name containing the HTML and XML files should also have
+# this name.
+
+ECLIPSE_DOC_ID         = org.doxygen.Project
+
+# The DISABLE_INDEX tag can be used to turn on/off the condensed index at
+# top of each HTML page. The value NO (the default) enables the index and
+# the value YES disables it.
+
+DISABLE_INDEX          = NO
+
+# This tag can be used to set the number of enum values (range [1..20])
+# that doxygen will group on one line in the generated HTML documentation.
+
+ENUM_VALUES_PER_LINE   = 4
+
+# The GENERATE_TREEVIEW tag is used to specify whether a tree-like index
+# structure should be generated to display hierarchical information.
+# If the tag value is set to YES, a side panel will be generated
+# containing a tree-like index structure (just like the one that
+# is generated for HTML Help). For this to work a browser that supports
+# JavaScript, DHTML, CSS and frames is required (i.e. any modern browser).
+# Windows users are probably better off using the HTML help feature.
+
+GENERATE_TREEVIEW      = NO
+
+# By enabling USE_INLINE_TREES, doxygen will generate the Groups, Directories,
+# and Class Hierarchy pages using a tree view instead of an ordered list.
+
+USE_INLINE_TREES       = NO
+
+# If the treeview is enabled (see GENERATE_TREEVIEW) then this tag can be
+# used to set the initial width (in pixels) of the frame in which the tree
+# is shown.
+
+TREEVIEW_WIDTH         = 250
+
+# When the EXT_LINKS_IN_WINDOW option is set to YES doxygen will open
+# links to external symbols imported via tag files in a separate window.
+
+EXT_LINKS_IN_WINDOW    = NO
+
+# Use this tag to change the font size of Latex formulas included
+# as images in the HTML documentation. The default is 10. Note that
+# when you change the font size after a successful doxygen run you need
+# to manually remove any form_*.png images from the HTML output directory
+# to force them to be regenerated.
+
+FORMULA_FONTSIZE       = 10
+
+# Use the FORMULA_TRANPARENT tag to determine whether or not the images
+# generated for formulas are transparent PNGs. Transparent PNGs are
+# not supported properly for IE 6.0, but are supported on all modern browsers.
+# Note that when changing this option you need to delete any form_*.png files
+# in the HTML output before the changes have effect.
+
+FORMULA_TRANSPARENT    = YES
+
+# When the SEARCHENGINE tag is enabled doxygen will generate a search box
+# for the HTML output. The underlying search engine uses javascript
+# and DHTML and should work on any modern browser. Note that when using
+# HTML help (GENERATE_HTMLHELP), Qt help (GENERATE_QHP), or docsets
+# (GENERATE_DOCSET) there is already a search function so this one should
+# typically be disabled. For large projects the javascript based search engine
+# can be slow, then enabling SERVER_BASED_SEARCH may provide a better solution.
+
+SEARCHENGINE           = YES
+
+# When the SERVER_BASED_SEARCH tag is enabled the search engine will be
+# implemented using a PHP enabled web server instead of at the web client
+# using Javascript. Doxygen will generate the search PHP script and index
+# file to put on the web server. The advantage of the server
+# based approach is that it scales better to large projects and allows
+# full text search. The disadvances is that it is more difficult to setup
+# and does not have live searching capabilities.
+
+SERVER_BASED_SEARCH    = NO
+
+#---------------------------------------------------------------------------
+# configuration options related to the LaTeX output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_LATEX tag is set to YES (the default) Doxygen will
+# generate Latex output.
+
+GENERATE_LATEX         = NO
+
+# The LATEX_OUTPUT tag is used to specify where the LaTeX docs will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be
+# put in front of it. If left blank `latex' will be used as the default path.
+
+LATEX_OUTPUT           = latex
+
+# The LATEX_CMD_NAME tag can be used to specify the LaTeX command name to be
+# invoked. If left blank `latex' will be used as the default command name.
+# Note that when enabling USE_PDFLATEX this option is only used for
+# generating bitmaps for formulas in the HTML output, but not in the
+# Makefile that is written to the output directory.
+
+LATEX_CMD_NAME         = latex
+
+# The MAKEINDEX_CMD_NAME tag can be used to specify the command name to
+# generate index for LaTeX. If left blank `makeindex' will be used as the
+# default command name.
+
+MAKEINDEX_CMD_NAME     = makeindex
+
+# If the COMPACT_LATEX tag is set to YES Doxygen generates more compact
+# LaTeX documents. This may be useful for small projects and may help to
+# save some trees in general.
+
+COMPACT_LATEX          = NO
+
+# The PAPER_TYPE tag can be used to set the paper type that is used
+# by the printer. Possible values are: a4, a4wide, letter, legal and
+# executive. If left blank a4wide will be used.
+
+PAPER_TYPE             = a4wide
+
+# The EXTRA_PACKAGES tag can be to specify one or more names of LaTeX
+# packages that should be included in the LaTeX output.
+
+EXTRA_PACKAGES         =
+
+# The LATEX_HEADER tag can be used to specify a personal LaTeX header for
+# the generated latex document. The header should contain everything until
+# the first chapter. If it is left blank doxygen will generate a
+# standard header. Notice: only use this tag if you know what you are doing!
+
+LATEX_HEADER           =
+
+# If the PDF_HYPERLINKS tag is set to YES, the LaTeX that is generated
+# is prepared for conversion to pdf (using ps2pdf). The pdf file will
+# contain links (just like the HTML output) instead of page references
+# This makes the output suitable for online browsing using a pdf viewer.
+
+PDF_HYPERLINKS         = YES
+
+# If the USE_PDFLATEX tag is set to YES, pdflatex will be used instead of
+# plain latex in the generated Makefile. Set this option to YES to get a
+# higher quality PDF documentation.
+
+USE_PDFLATEX           = YES
+
+# If the LATEX_BATCHMODE tag is set to YES, doxygen will add the \\batchmode.
+# command to the generated LaTeX files. This will instruct LaTeX to keep
+# running if errors occur, instead of asking the user for help.
+# This option is also used when generating formulas in HTML.
+
+LATEX_BATCHMODE        = NO
+
+# If LATEX_HIDE_INDICES is set to YES then doxygen will not
+# include the index chapters (such as File Index, Compound Index, etc.)
+# in the output.
+
+LATEX_HIDE_INDICES     = NO
+
+# If LATEX_SOURCE_CODE is set to YES then doxygen will include
+# source code with syntax highlighting in the LaTeX output.
+# Note that which sources are shown also depends on other settings
+# such as SOURCE_BROWSER.
+
+LATEX_SOURCE_CODE      = NO
+
+#---------------------------------------------------------------------------
+# configuration options related to the RTF output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_RTF tag is set to YES Doxygen will generate RTF output
+# The RTF output is optimized for Word 97 and may not look very pretty with
+# other RTF readers or editors.
+
+GENERATE_RTF           = NO
+
+# The RTF_OUTPUT tag is used to specify where the RTF docs will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be
+# put in front of it. If left blank `rtf' will be used as the default path.
+
+RTF_OUTPUT             = rtf
+
+# If the COMPACT_RTF tag is set to YES Doxygen generates more compact
+# RTF documents. This may be useful for small projects and may help to
+# save some trees in general.
+
+COMPACT_RTF            = NO
+
+# If the RTF_HYPERLINKS tag is set to YES, the RTF that is generated
+# will contain hyperlink fields. The RTF file will
+# contain links (just like the HTML output) instead of page references.
+# This makes the output suitable for online browsing using WORD or other
+# programs which support those fields.
+# Note: wordpad (write) and others do not support links.
+
+RTF_HYPERLINKS         = NO
+
+# Load stylesheet definitions from file. Syntax is similar to doxygen's
+# config file, i.e. a series of assignments. You only have to provide
+# replacements, missing definitions are set to their default value.
+
+RTF_STYLESHEET_FILE    =
+
+# Set optional variables used in the generation of an rtf document.
+# Syntax is similar to doxygen's config file.
+
+RTF_EXTENSIONS_FILE    =
+
+#---------------------------------------------------------------------------
+# configuration options related to the man page output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_MAN tag is set to YES (the default) Doxygen will
+# generate man pages
+
+GENERATE_MAN           = YES
+
+# The MAN_OUTPUT tag is used to specify where the man pages will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be
+# put in front of it. If left blank `man' will be used as the default path.
+
+MAN_OUTPUT             = man
+
+# The MAN_EXTENSION tag determines the extension that is added to
+# the generated man pages (default is the subroutine's section .3)
+
+MAN_EXTENSION          = .3
+
+# If the MAN_LINKS tag is set to YES and Doxygen generates man output,
+# then it will generate one additional man file for each entity
+# documented in the real man page(s). These additional files
+# only source the real man page, but without them the man command
+# would be unable to find the correct page. The default is NO.
+
+MAN_LINKS              = NO
+
+#---------------------------------------------------------------------------
+# configuration options related to the XML output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_XML tag is set to YES Doxygen will
+# generate an XML file that captures the structure of
+# the code including all documentation.
+
+GENERATE_XML           = NO
+
+# The XML_OUTPUT tag is used to specify where the XML pages will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be
+# put in front of it. If left blank `xml' will be used as the default path.
+
+XML_OUTPUT             = xml
+
+# The XML_SCHEMA tag can be used to specify an XML schema,
+# which can be used by a validating XML parser to check the
+# syntax of the XML files.
+
+XML_SCHEMA             =
+
+# The XML_DTD tag can be used to specify an XML DTD,
+# which can be used by a validating XML parser to check the
+# syntax of the XML files.
+
+XML_DTD                =
+
+# If the XML_PROGRAMLISTING tag is set to YES Doxygen will
+# dump the program listings (including syntax highlighting
+# and cross-referencing information) to the XML output. Note that
+# enabling this will significantly increase the size of the XML output.
+
+XML_PROGRAMLISTING     = YES
+
+#---------------------------------------------------------------------------
+# configuration options for the AutoGen Definitions output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_AUTOGEN_DEF tag is set to YES Doxygen will
+# generate an AutoGen Definitions (see autogen.sf.net) file
+# that captures the structure of the code including all
+# documentation. Note that this feature is still experimental
+# and incomplete at the moment.
+
+GENERATE_AUTOGEN_DEF   = NO
+
+#---------------------------------------------------------------------------
+# configuration options related to the Perl module output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_PERLMOD tag is set to YES Doxygen will
+# generate a Perl module file that captures the structure of
+# the code including all documentation. Note that this
+# feature is still experimental and incomplete at the
+# moment.
+
+GENERATE_PERLMOD       = NO
+
+# If the PERLMOD_LATEX tag is set to YES Doxygen will generate
+# the necessary Makefile rules, Perl scripts and LaTeX code to be able
+# to generate PDF and DVI output from the Perl module output.
+
+PERLMOD_LATEX          = NO
+
+# If the PERLMOD_PRETTY tag is set to YES the Perl module output will be
+# nicely formatted so it can be parsed by a human reader.
+# This is useful
+# if you want to understand what is going on.
+# On the other hand, if this
+# tag is set to NO the size of the Perl module output will be much smaller
+# and Perl will parse it just the same.
+
+PERLMOD_PRETTY         = YES
+
+# The names of the make variables in the generated doxyrules.make file
+# are prefixed with the string contained in PERLMOD_MAKEVAR_PREFIX.
+# This is useful so different doxyrules.make files included by the same
+# Makefile don't overwrite each other's variables.
+
+PERLMOD_MAKEVAR_PREFIX =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the preprocessor
+#---------------------------------------------------------------------------
+
+# If the ENABLE_PREPROCESSING tag is set to YES (the default) Doxygen will
+# evaluate all C-preprocessor directives found in the sources and include
+# files.
+
+ENABLE_PREPROCESSING   = YES
+
+# If the MACRO_EXPANSION tag is set to YES Doxygen will expand all macro
+# names in the source code. If set to NO (the default) only conditional
+# compilation will be performed. Macro expansion can be done in a controlled
+# way by setting EXPAND_ONLY_PREDEF to YES.
+
+MACRO_EXPANSION        = NO
+
+# If the EXPAND_ONLY_PREDEF and MACRO_EXPANSION tags are both set to YES
+# then the macro expansion is limited to the macros specified with the
+# PREDEFINED and EXPAND_AS_DEFINED tags.
+
+EXPAND_ONLY_PREDEF     = NO
+
+# If the SEARCH_INCLUDES tag is set to YES (the default) the includes files
+# in the INCLUDE_PATH (see below) will be search if a #include is found.
+
+SEARCH_INCLUDES        = YES
+
+# The INCLUDE_PATH tag can be used to specify one or more directories that
+# contain include files that are not input files but should be processed by
+# the preprocessor.
+
+INCLUDE_PATH           =
+
+# You can use the INCLUDE_FILE_PATTERNS tag to specify one or more wildcard
+# patterns (like *.h and *.hpp) to filter out the header-files in the
+# directories. If left blank, the patterns specified with FILE_PATTERNS will
+# be used.
+
+INCLUDE_FILE_PATTERNS  =
+
+# The PREDEFINED tag can be used to specify one or more macro names that
+# are defined before the preprocessor is started (similar to the -D option of
+# gcc). The argument of the tag is a list of macros of the form: name
+# or name=definition (no spaces). If the definition and the = are
+# omitted =1 is assumed. To prevent a macro definition from being
+# undefined via #undef or recursively expanded use the := operator
+# instead of the = operator.
+
+PREDEFINED             = DEBUG=2 __GNUC__=1
+
+# If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then
+# this tag can be used to specify a list of macro names that should be expanded.
+# The macro definition that is found in the sources will be used.
+# Use the PREDEFINED tag if you want to use a different macro definition.
+
+EXPAND_AS_DEFINED      =
+
+# If the SKIP_FUNCTION_MACROS tag is set to YES (the default) then
+# doxygen's preprocessor will remove all function-like macros that are alone
+# on a line, have an all uppercase name, and do not end with a semicolon. Such
+# function macros are typically used for boiler-plate code, and will confuse
+# the parser if not removed.
+
+SKIP_FUNCTION_MACROS   = YES
+
+#---------------------------------------------------------------------------
+# Configuration::additions related to external references
+#---------------------------------------------------------------------------
+
+# The TAGFILES option can be used to specify one or more tagfiles.
+# Optionally an initial location of the external documentation
+# can be added for each tagfile. The format of a tag file without
+# this location is as follows:
+#
+# TAGFILES = file1 file2 ...
+# Adding location for the tag files is done as follows:
+#
+# TAGFILES = file1=loc1 "file2 = loc2" ...
+# where "loc1" and "loc2" can be relative or absolute paths or
+# URLs. If a location is present for each tag, the installdox tool
+# does not have to be run to correct the links.
+# Note that each tag file must have a unique name
+# (where the name does NOT include the path)
+# If a tag file is not located in the directory in which doxygen
+# is run, you must also specify the path to the tagfile here.
+
+TAGFILES               = tooltag=./man1
+
+# When a file name is specified after GENERATE_TAGFILE, doxygen will create
+# a tag file that is based on the input files it reads.
+
+GENERATE_TAGFILE       =
+
+# If the ALLEXTERNALS tag is set to YES all external classes will be listed
+# in the class index. If set to NO only the inherited external classes
+# will be listed.
+
+ALLEXTERNALS           = NO
+
+# If the EXTERNAL_GROUPS tag is set to YES all external groups will be listed
+# in the modules index. If set to NO, only the current project's groups will
+# be listed.
+
+EXTERNAL_GROUPS        = YES
+
+# The PERL_PATH should be the absolute path and name of the perl script
+# interpreter (i.e. the result of `which perl').
+
+PERL_PATH              = /usr/bin/perl
+
+#---------------------------------------------------------------------------
+# Configuration options related to the dot tool
+#---------------------------------------------------------------------------
+
+# If the CLASS_DIAGRAMS tag is set to YES (the default) Doxygen will
+# generate a inheritance diagram (in HTML, RTF and LaTeX) for classes with base
+# or super classes. Setting the tag to NO turns the diagrams off. Note that
+# this option is superseded by the HAVE_DOT option below. This is only a
+# fallback. It is recommended to install and use dot, since it yields more
+# powerful graphs.
+
+CLASS_DIAGRAMS         = YES
+
+# You can define message sequence charts within doxygen comments using the \msc
+# command. Doxygen will then run the mscgen tool (see
+# http://www.mcternan.me.uk/mscgen/) to produce the chart and insert it in the
+# documentation. The MSCGEN_PATH tag allows you to specify the directory where
+# the mscgen tool resides. If left empty the tool is assumed to be found in the
+# default search path.
+
+MSCGEN_PATH            =
+
+# If set to YES, the inheritance and collaboration graphs will hide
+# inheritance and usage relations if the target is undocumented
+# or is not a class.
+
+HIDE_UNDOC_RELATIONS   = YES
+
+# If you set the HAVE_DOT tag to YES then doxygen will assume the dot tool is
+# available from the path. This tool is part of Graphviz, a graph visualization
+# toolkit from AT&T and Lucent Bell Labs. The other options in this section
+# have no effect if this option is set to NO (the default)
+
+HAVE_DOT               = NO
+
+# The DOT_NUM_THREADS specifies the number of dot invocations doxygen is
+# allowed to run in parallel. When set to 0 (the default) doxygen will
+# base this on the number of processors available in the system. You can set it
+# explicitly to a value larger than 0 to get control over the balance
+# between CPU load and processing speed.
+
+DOT_NUM_THREADS        = 0
+
+# By default doxygen will write a font called FreeSans.ttf to the output
+# directory and reference it in all dot files that doxygen generates. This
+# font does not include all possible unicode characters however, so when you need
+# these (or just want a differently looking font) you can specify the font name
+# using DOT_FONTNAME. You need need to make sure dot is able to find the font,
+# which can be done by putting it in a standard location or by setting the
+# DOTFONTPATH environment variable or by setting DOT_FONTPATH to the directory
+# containing the font.
+
+DOT_FONTNAME           = FreeSans.ttf
+
+# The DOT_FONTSIZE tag can be used to set the size of the font of dot graphs.
+# The default size is 10pt.
+
+DOT_FONTSIZE           = 10
+
+# By default doxygen will tell dot to use the output directory to look for the
+# FreeSans.ttf font (which doxygen will put there itself). If you specify a
+# different font using DOT_FONTNAME you can set the path where dot
+# can find it using this tag.
+
+DOT_FONTPATH           =
+
+# If the CLASS_GRAPH and HAVE_DOT tags are set to YES then doxygen
+# will generate a graph for each documented class showing the direct and
+# indirect inheritance relations. Setting this tag to YES will force the
+# the CLASS_DIAGRAMS tag to NO.
+
+CLASS_GRAPH            = YES
+
+# If the COLLABORATION_GRAPH and HAVE_DOT tags are set to YES then doxygen
+# will generate a graph for each documented class showing the direct and
+# indirect implementation dependencies (inheritance, containment, and
+# class references variables) of the class with other documented classes.
+
+COLLABORATION_GRAPH    = YES
+
+# If the GROUP_GRAPHS and HAVE_DOT tags are set to YES then doxygen
+# will generate a graph for groups, showing the direct groups dependencies
+
+GROUP_GRAPHS           = YES
+
+# If the UML_LOOK tag is set to YES doxygen will generate inheritance and
+# collaboration diagrams in a style similar to the OMG's Unified Modeling
+# Language.
+
+UML_LOOK               = NO
+
+# If set to YES, the inheritance and collaboration graphs will show the
+# relations between templates and their instances.
+
+TEMPLATE_RELATIONS     = NO
+
+# If the ENABLE_PREPROCESSING, SEARCH_INCLUDES, INCLUDE_GRAPH, and HAVE_DOT
+# tags are set to YES then doxygen will generate a graph for each documented
+# file showing the direct and indirect include dependencies of the file with
+# other documented files.
+
+INCLUDE_GRAPH          = YES
+
+# If the ENABLE_PREPROCESSING, SEARCH_INCLUDES, INCLUDED_BY_GRAPH, and
+# HAVE_DOT tags are set to YES then doxygen will generate a graph for each
+# documented header file showing the documented files that directly or
+# indirectly include this file.
+
+INCLUDED_BY_GRAPH      = YES
+
+# If the CALL_GRAPH and HAVE_DOT options are set to YES then
+# doxygen will generate a call dependency graph for every global function
+# or class method. Note that enabling this option will significantly increase
+# the time of a run. So in most cases it will be better to enable call graphs
+# for selected functions only using the \callgraph command.
+
+CALL_GRAPH             = NO
+
+# If the CALLER_GRAPH and HAVE_DOT tags are set to YES then
+# doxygen will generate a caller dependency graph for every global function
+# or class method. Note that enabling this option will significantly increase
+# the time of a run. So in most cases it will be better to enable caller
+# graphs for selected functions only using the \callergraph command.
+
+CALLER_GRAPH           = NO
+
+# If the GRAPHICAL_HIERARCHY and HAVE_DOT tags are set to YES then doxygen
+# will graphical hierarchy of all classes instead of a textual one.
+
+GRAPHICAL_HIERARCHY    = YES
+
+# If the DIRECTORY_GRAPH, SHOW_DIRECTORIES and HAVE_DOT tags are set to YES
+# then doxygen will show the dependencies a directory has on other directories
+# in a graphical way. The dependency relations are determined by the #include
+# relations between the files in the directories.
+
+DIRECTORY_GRAPH        = YES
+
+# The DOT_IMAGE_FORMAT tag can be used to set the image format of the images
+# generated by dot. Possible values are png, jpg, or gif
+# If left blank png will be used.
+
+DOT_IMAGE_FORMAT       = png
+
+# The tag DOT_PATH can be used to specify the path where the dot tool can be
+# found. If left blank, it is assumed the dot tool can be found in the path.
+
+DOT_PATH               =
+
+# The DOTFILE_DIRS tag can be used to specify one or more directories that
+# contain dot files that are included in the documentation (see the
+# \dotfile command).
+
+DOTFILE_DIRS           =
+
+# The DOT_GRAPH_MAX_NODES tag can be used to set the maximum number of
+# nodes that will be shown in the graph. If the number of nodes in a graph
+# becomes larger than this value, doxygen will truncate the graph, which is
+# visualized by representing a node as a red box. Note that doxygen if the
+# number of direct children of the root node in a graph is already larger than
+# DOT_GRAPH_MAX_NODES then the graph will not be shown at all. Also note
+# that the size of a graph can be further restricted by MAX_DOT_GRAPH_DEPTH.
+
+DOT_GRAPH_MAX_NODES    = 50
+
+# The MAX_DOT_GRAPH_DEPTH tag can be used to set the maximum depth of the
+# graphs generated by dot. A depth value of 3 means that only nodes reachable
+# from the root by following a path via at most 3 edges will be shown. Nodes
+# that lay further from the root node will be omitted. Note that setting this
+# option to 1 or 2 may greatly reduce the computation time needed for large
+# code bases. Also note that the size of a graph can be further restricted by
+# DOT_GRAPH_MAX_NODES. Using a depth of 0 means no depth restriction.
+
+MAX_DOT_GRAPH_DEPTH    = 0
+
+# Set the DOT_TRANSPARENT tag to YES to generate images with a transparent
+# background. This is disabled by default, because dot on Windows does not
+# seem to support this out of the box. Warning: Depending on the platform used,
+# enabling this option may lead to badly anti-aliased labels on the edges of
+# a graph (i.e. they become hard to read).
+
+DOT_TRANSPARENT        = NO
+
+# Set the DOT_MULTI_TARGETS tag to YES allow dot to generate multiple output
+# files in one run (i.e. multiple -o and -T options on the command line). This
+# makes dot run faster, but since only newer versions of dot (>1.8.10)
+# support this, this feature is disabled by default.
+
+DOT_MULTI_TARGETS      = YES
+
+# If the GENERATE_LEGEND tag is set to YES (the default) Doxygen will
+# generate a legend page explaining the meaning of the various boxes and
+# arrows in the dot generated graphs.
+
+GENERATE_LEGEND        = YES
+
+# If the DOT_CLEANUP tag is set to YES (the default) Doxygen will
+# remove the intermediate dot files that are used to generate
+# the various graphs.
+
+DOT_CLEANUP            = YES
diff --git a/external/db_drivers/liblmdb64/LICENSE b/external/db_drivers/liblmdb64/LICENSE
new file mode 100644
index 000000000..05ad7571e
--- /dev/null
+++ b/external/db_drivers/liblmdb64/LICENSE
@@ -0,0 +1,47 @@
+The OpenLDAP Public License
+  Version 2.8, 17 August 2003
+
+Redistribution and use of this software and associated documentation
+("Software"), with or without modification, are permitted provided
+that the following conditions are met:
+
+1. Redistributions in source form must retain copyright statements
+   and notices,
+
+2. Redistributions in binary form must reproduce applicable copyright
+   statements and notices, this list of conditions, and the following
+   disclaimer in the documentation and/or other materials provided
+   with the distribution, and
+
+3. Redistributions must contain a verbatim copy of this document.
+
+The OpenLDAP Foundation may revise this license from time to time.
+Each revision is distinguished by a version number.  You may use
+this Software under terms of this license revision or under the
+terms of any subsequent revision of the license.
+
+THIS SOFTWARE IS PROVIDED BY THE OPENLDAP FOUNDATION AND ITS
+CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
+INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT
+SHALL THE OPENLDAP FOUNDATION, ITS CONTRIBUTORS, OR THE AUTHOR(S)
+OR OWNER(S) OF THE SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+The names of the authors and copyright holders must not be used in
+advertising or otherwise to promote the sale, use or other dealing
+in this Software without specific, written prior permission.  Title
+to copyright in this Software shall at all times remain with copyright
+holders.
+
+OpenLDAP is a registered trademark of the OpenLDAP Foundation.
+
+Copyright 1999-2003 The OpenLDAP Foundation, Redwood City,
+California, USA.  All Rights Reserved.  Permission to copy and
+distribute verbatim copies of this document is granted.
diff --git a/external/db_drivers/liblmdb/Makefile b/external/db_drivers/liblmdb64/Makefile
index 2d0983eff..2d0983eff 100644
--- a/external/db_drivers/liblmdb/Makefile
+++ b/external/db_drivers/liblmdb64/Makefile
diff --git a/external/db_drivers/liblmdb/lmdb.h b/external/db_drivers/liblmdb64/lmdb.h
index ebfbc5dc8..ebfbc5dc8 100644
--- a/external/db_drivers/liblmdb/lmdb.h
+++ b/external/db_drivers/liblmdb64/lmdb.h
diff --git a/external/db_drivers/liblmdb/mdb.c b/external/db_drivers/liblmdb64/mdb.c
index c4dc26903..c4dc26903 100644
--- a/external/db_drivers/liblmdb/mdb.c
+++ b/external/db_drivers/liblmdb64/mdb.c
diff --git a/external/db_drivers/liblmdb64/mdb_copy.1 b/external/db_drivers/liblmdb64/mdb_copy.1
new file mode 100644
index 000000000..094b26056
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mdb_copy.1
@@ -0,0 +1,54 @@
+.TH MDB_COPY 1 "2014/06/20" "LMDB 0.9.14"
+.\" Copyright 2012-2014 Howard Chu, Symas Corp. All Rights Reserved.
+.\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
+.SH NAME
+mdb_copy \- LMDB environment copy tool
+.SH SYNOPSIS
+.B mdb_copy
+[\c
+.BR \-V ]
+[\c
+.BR \-c ]
+[\c
+.BR \-n ]
+.B srcpath
+[\c
+.BR dstpath ]
+.SH DESCRIPTION
+The
+.B mdb_copy
+utility copies an LMDB environment. The environment can
+be copied regardless of whether it is currently in use.
+No lockfile is created, since it gets recreated at need.
+
+If
+.I dstpath
+is specified it must be the path of an empty directory
+for storing the backup. Otherwise, the backup will be
+written to stdout.
+
+.SH OPTIONS
+.TP
+.BR \-V
+Write the library version number to the standard output, and exit.
+.TP
+.BR \-c
+Compact while copying. Only current data pages will be copied; freed
+or unused pages will be omitted from the copy. This option will
+slow down the backup process as it is more CPU-intensive.
+.TP
+.BR \-n
+Open LDMB environment(s) which do not use subdirectories.
+
+.SH DIAGNOSTICS
+Exit status is zero if no errors occur.
+Errors result in a non-zero exit status and
+a diagnostic message being written to standard error.
+.SH CAVEATS
+This utility can trigger significant file size growth if run
+in parallel with write transactions, because pages which they
+free during copying cannot be reused until the copy is done.
+.SH "SEE ALSO"
+.BR mdb_stat (1)
+.SH AUTHOR
+Howard Chu of Symas Corporation <http://www.symas.com>
diff --git a/external/db_drivers/liblmdb/mdb_copy.c b/external/db_drivers/liblmdb64/mdb_copy.c
index af0a94111..af0a94111 100644
--- a/external/db_drivers/liblmdb/mdb_copy.c
+++ b/external/db_drivers/liblmdb64/mdb_copy.c
diff --git a/external/db_drivers/liblmdb64/mdb_dump.1 b/external/db_drivers/liblmdb64/mdb_dump.1
new file mode 100644
index 000000000..6fcc93081
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mdb_dump.1
@@ -0,0 +1,75 @@
+.TH MDB_DUMP 1 "2014/06/20" "LMDB 0.9.14"
+.\" Copyright 2014 Howard Chu, Symas Corp. All Rights Reserved.
+.\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
+.SH NAME
+mdb_dump \- LMDB environment export tool
+.SH SYNOPSIS
+.B mdb_dump
+.BR \ envpath
+[\c
+.BR \-V ]
+[\c
+.BI \-f \ file\fR]
+[\c
+.BR \-l ]
+[\c
+.BR \-n ]
+[\c
+.BR \-p ]
+[\c
+.BR \-a \ |
+.BI \-s \ subdb\fR]
+.SH DESCRIPTION
+The
+.B mdb_dump
+utility reads a database and writes its contents to the
+standard output using a portable flat-text format
+understood by the
+.BR mdb_load (1)
+utility.
+.SH OPTIONS
+.TP
+.BR \-V
+Write the library version number to the standard output, and exit.
+.TP
+.BR \-f \ file
+Write to the specified file instead of to the standard output.
+.TP
+.BR \-l
+List the databases stored in the environment. Just the
+names will be listed, no data will be output.
+.TP
+.BR \-n
+Dump an LMDB database which does not use subdirectories.
+.TP
+.BR \-p
+If characters in either the key or data items are printing characters (as
+defined by isprint(3)), output them directly. This option permits users to
+use standard text editors and tools to modify the contents of databases.
+
+Note: different systems may have different notions about what characters
+are considered printing characters, and databases dumped in this manner may
+be less portable to external systems. 
+.TP
+.BR \-a
+Dump all of the subdatabases in the environment.
+.TP
+.BR \-s \ subdb
+Dump a specific subdatabase. If no database is specified, only the main database is dumped.
+.SH DIAGNOSTICS
+Exit status is zero if no errors occur.
+Errors result in a non-zero exit status and
+a diagnostic message being written to standard error.
+
+Dumping and reloading databases that use user-defined comparison functions
+will result in new databases that use the default comparison functions.
+\fBIn this case it is quite likely that the reloaded database will be
+damaged beyond repair permitting neither record storage nor retrieval.\fP
+
+The only available workaround is to modify the source for the
+.BR mdb_load (1)
+utility to load the database using the correct comparison functions.
+.SH "SEE ALSO"
+.BR mdb_load (1)
+.SH AUTHOR
+Howard Chu of Symas Corporation <http://www.symas.com>
diff --git a/external/db_drivers/liblmdb64/mdb_dump.c b/external/db_drivers/liblmdb64/mdb_dump.c
new file mode 100644
index 000000000..0eb85fd20
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mdb_dump.c
@@ -0,0 +1,317 @@
+/* mdb_dump.c - memory-mapped database dump tool */
+/*
+ * Copyright 2011-2014 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <unistd.h>
+#include <signal.h>
+#include "lmdb.h"
+
+#ifdef _WIN32
+#define Z	"I"
+#else
+#define Z	"z"
+#endif
+
+#define PRINT	1
+static int mode;
+
+typedef struct flagbit {
+	int bit;
+	char *name;
+} flagbit;
+
+flagbit dbflags[] = {
+	{ MDB_REVERSEKEY, "reversekey" },
+	{ MDB_DUPSORT, "dupsort" },
+	{ MDB_INTEGERKEY, "integerkey" },
+	{ MDB_DUPFIXED, "dupfixed" },
+	{ MDB_INTEGERDUP, "integerdup" },
+	{ MDB_REVERSEDUP, "reversedup" },
+	{ 0, NULL }
+};
+
+static volatile sig_atomic_t gotsig;
+
+static void dumpsig( int sig )
+{
+	gotsig=1;
+}
+
+static const char hexc[] = "0123456789abcdef";
+
+static void hex(unsigned char c)
+{
+	putchar(hexc[c >> 4]);
+	putchar(hexc[c & 0xf]);
+}
+
+static void text(MDB_val *v)
+{
+	unsigned char *c, *end;
+
+	putchar(' ');
+	c = v->mv_data;
+	end = c + v->mv_size;
+	while (c < end) {
+		if (isprint(*c)) {
+			putchar(*c);
+		} else {
+			putchar('\\');
+			hex(*c);
+		}
+		c++;
+	}
+	putchar('\n');
+}
+
+static void byte(MDB_val *v)
+{
+	unsigned char *c, *end;
+
+	putchar(' ');
+	c = v->mv_data;
+	end = c + v->mv_size;
+	while (c < end) {
+		hex(*c++);
+	}
+	putchar('\n');
+}
+
+/* Dump in BDB-compatible format */
+static int dumpit(MDB_txn *txn, MDB_dbi dbi, char *name)
+{
+	MDB_cursor *mc;
+	MDB_stat ms;
+	MDB_val key, data;
+	MDB_envinfo info;
+	unsigned int flags;
+	int rc, i;
+
+	rc = mdb_dbi_flags(txn, dbi, &flags);
+	if (rc) return rc;
+
+	rc = mdb_stat(txn, dbi, &ms);
+	if (rc) return rc;
+
+	rc = mdb_env_info(mdb_txn_env(txn), &info);
+	if (rc) return rc;
+
+	printf("VERSION=3\n");
+	printf("format=%s\n", mode & PRINT ? "print" : "bytevalue");
+	if (name)
+		printf("database=%s\n", name);
+	printf("type=btree\n");
+	printf("mapsize=%" Z "u\n", info.me_mapsize);
+	if (info.me_mapaddr)
+		printf("mapaddr=%p\n", info.me_mapaddr);
+	printf("maxreaders=%u\n", info.me_maxreaders);
+
+	if (flags & MDB_DUPSORT)
+		printf("duplicates=1\n");
+
+	for (i=0; dbflags[i].bit; i++)
+		if (flags & dbflags[i].bit)
+			printf("%s=1\n", dbflags[i].name);
+
+	printf("db_pagesize=%d\n", ms.ms_psize);
+	printf("HEADER=END\n");
+
+	rc = mdb_cursor_open(txn, dbi, &mc);
+	if (rc) return rc;
+
+	while ((rc = mdb_cursor_get(mc, &key, &data, MDB_NEXT) == MDB_SUCCESS)) {
+		if (gotsig) {
+			rc = EINTR;
+			break;
+		}
+		if (mode & PRINT) {
+			text(&key);
+			text(&data);
+		} else {
+			byte(&key);
+			byte(&data);
+		}
+	}
+	printf("DATA=END\n");
+	if (rc == MDB_NOTFOUND)
+		rc = MDB_SUCCESS;
+
+	return rc;
+}
+
+static void usage(char *prog)
+{
+	fprintf(stderr, "usage: %s dbpath [-V] [-f output] [-l] [-n] [-p] [-a|-s subdb]\n", prog);
+	exit(EXIT_FAILURE);
+}
+
+int main(int argc, char *argv[])
+{
+	int i, rc;
+	MDB_env *env;
+	MDB_txn *txn;
+	MDB_dbi dbi;
+	char *prog = argv[0];
+	char *envname;
+	char *subname = NULL;
+	int alldbs = 0, envflags = 0, list = 0;
+
+	if (argc < 2) {
+		usage(prog);
+	}
+
+	/* -a: dump main DB and all subDBs
+	 * -s: dump only the named subDB
+	 * -n: use NOSUBDIR flag on env_open
+	 * -p: use printable characters
+	 * -f: write to file instead of stdout
+	 * -V: print version and exit
+	 * (default) dump only the main DB
+	 */
+	while ((i = getopt(argc, argv, "af:lnps:V")) != EOF) {
+		switch(i) {
+		case 'V':
+			printf("%s\n", MDB_VERSION_STRING);
+			exit(0);
+			break;
+		case 'l':
+			list = 1;
+			/*FALLTHROUGH*/;
+		case 'a':
+			if (subname)
+				usage(prog);
+			alldbs++;
+			break;
+		case 'f':
+			if (freopen(optarg, "w", stdout) == NULL) {
+				fprintf(stderr, "%s: %s: reopen: %s\n",
+					prog, optarg, strerror(errno));
+				exit(EXIT_FAILURE);
+			}
+			break;
+		case 'n':
+			envflags |= MDB_NOSUBDIR;
+			break;
+		case 'p':
+			mode |= PRINT;
+			break;
+		case 's':
+			if (alldbs)
+				usage(prog);
+			subname = optarg;
+			break;
+		default:
+			usage(prog);
+		}
+	}
+
+	if (optind != argc - 1)
+		usage(prog);
+
+#ifdef SIGPIPE
+	signal(SIGPIPE, dumpsig);
+#endif
+#ifdef SIGHUP
+	signal(SIGHUP, dumpsig);
+#endif
+	signal(SIGINT, dumpsig);
+	signal(SIGTERM, dumpsig);
+
+	envname = argv[optind];
+	rc = mdb_env_create(&env);
+	if (rc) {
+		fprintf(stderr, "mdb_env_create failed, error %d %s\n", rc, mdb_strerror(rc));
+		return EXIT_FAILURE;
+	}
+
+	if (alldbs || subname) {
+		mdb_env_set_maxdbs(env, 2);
+	}
+
+	rc = mdb_env_open(env, envname, envflags | MDB_RDONLY, 0664);
+	if (rc) {
+		fprintf(stderr, "mdb_env_open failed, error %d %s\n", rc, mdb_strerror(rc));
+		goto env_close;
+	}
+
+	rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
+	if (rc) {
+		fprintf(stderr, "mdb_txn_begin failed, error %d %s\n", rc, mdb_strerror(rc));
+		goto env_close;
+	}
+
+	rc = mdb_open(txn, subname, 0, &dbi);
+	if (rc) {
+		fprintf(stderr, "mdb_open failed, error %d %s\n", rc, mdb_strerror(rc));
+		goto txn_abort;
+	}
+
+	if (alldbs) {
+		MDB_cursor *cursor;
+		MDB_val key;
+		int count = 0;
+
+		rc = mdb_cursor_open(txn, dbi, &cursor);
+		if (rc) {
+			fprintf(stderr, "mdb_cursor_open failed, error %d %s\n", rc, mdb_strerror(rc));
+			goto txn_abort;
+		}
+		while ((rc = mdb_cursor_get(cursor, &key, NULL, MDB_NEXT_NODUP)) == 0) {
+			char *str;
+			MDB_dbi db2;
+			if (memchr(key.mv_data, '\0', key.mv_size))
+				continue;
+			count++;
+			str = malloc(key.mv_size+1);
+			memcpy(str, key.mv_data, key.mv_size);
+			str[key.mv_size] = '\0';
+			rc = mdb_open(txn, str, 0, &db2);
+			if (rc == MDB_SUCCESS) {
+				if (list) {
+					printf("%s\n", str);
+					list++;
+				} else {
+					rc = dumpit(txn, db2, str);
+					if (rc)
+						break;
+				}
+				mdb_close(env, db2);
+			}
+			free(str);
+			if (rc) continue;
+		}
+		mdb_cursor_close(cursor);
+		if (!count) {
+			fprintf(stderr, "%s: %s does not contain multiple databases\n", prog, envname);
+			rc = MDB_NOTFOUND;
+		} else if (rc == MDB_NOTFOUND) {
+			rc = MDB_SUCCESS;
+		}
+	} else {
+		rc = dumpit(txn, dbi, subname);
+	}
+	if (rc && rc != MDB_NOTFOUND)
+		fprintf(stderr, "%s: %s: %s\n", prog, envname, mdb_strerror(rc));
+
+	mdb_close(env, dbi);
+txn_abort:
+	mdb_txn_abort(txn);
+env_close:
+	mdb_env_close(env);
+
+	return rc ? EXIT_FAILURE : EXIT_SUCCESS;
+}
diff --git a/external/db_drivers/liblmdb64/mdb_load.1 b/external/db_drivers/liblmdb64/mdb_load.1
new file mode 100644
index 000000000..728024010
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mdb_load.1
@@ -0,0 +1,77 @@
+.TH MDB_LOAD 1 "2014/06/20" "LMDB 0.9.14"
+.\" Copyright 2014 Howard Chu, Symas Corp. All Rights Reserved.
+.\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
+.SH NAME
+mdb_load \- LMDB environment import tool
+.SH SYNOPSIS
+.B mdb_load
+.BR \ envpath
+[\c
+.BR \-V ]
+[\c
+.BI \-f \ file\fR]
+[\c
+.BR \-n ]
+[\c
+.BI \-s \ subdb\fR]
+[\c
+.BR \-N ]
+[\c
+.BR \-T ]
+.SH DESCRIPTION
+The
+.B mdb_load
+utility reads from the standard input and loads it into the
+LMDB environment
+.BR envpath .
+
+The input to
+.B mdb_load
+must be in the output format specified by the
+.BR mdb_dump (1)
+utility or as specified by the
+.B -T
+option below.
+.SH OPTIONS
+.TP
+.BR \-V
+Write the library version number to the standard output, and exit.
+.TP
+.BR \-f \ file
+Read from the specified file instead of from the standard input.
+.TP
+.BR \-n
+Load an LMDB database which does not use subdirectories.
+.TP
+.BR \-s \ subdb
+Load a specific subdatabase. If no database is specified, data is loaded into the main database.
+.TP
+.BR \-N
+Don't overwrite existing records when loading into an already existing database; just skip them.
+.TP
+.BR \-T
+Load data from simple text files. The input must be paired lines of text, where the first
+line of the pair is the key item, and the second line of the pair is its corresponding
+data item.
+
+A simple escape mechanism, where newline and backslash (\\) characters are special, is
+applied to the text input. Newline characters are interpreted as record separators.
+Backslash characters in the text will be interpreted in one of two ways: If the backslash
+character precedes another backslash character, the pair will be interpreted as a literal
+backslash. If the backslash character precedes any other character, the two characters
+following the backslash will be interpreted as a hexadecimal specification of a single
+character; for example, \\0a is a newline character in the ASCII character set.
+
+For this reason, any backslash or newline characters that naturally occur in the text
+input must be escaped to avoid misinterpretation by
+.BR mdb_load . 
+
+.SH DIAGNOSTICS
+Exit status is zero if no errors occur.
+Errors result in a non-zero exit status and
+a diagnostic message being written to standard error.
+
+.SH "SEE ALSO"
+.BR mdb_dump (1)
+.SH AUTHOR
+Howard Chu of Symas Corporation <http://www.symas.com>
diff --git a/external/db_drivers/liblmdb64/mdb_load.c b/external/db_drivers/liblmdb64/mdb_load.c
new file mode 100644
index 000000000..e0d95e13c
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mdb_load.c
@@ -0,0 +1,452 @@
+/* mdb_load.c - memory-mapped database load tool */
+/*
+ * Copyright 2011-2014 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <ctype.h>
+#include <unistd.h>
+#include "lmdb.h"
+
+#define PRINT	1
+#define NOHDR	2
+static int mode;
+
+static char *subname = NULL;
+
+static size_t lineno;
+static int version;
+
+static int flags;
+
+static char *prog;
+
+static int Eof;
+
+static MDB_envinfo info;
+
+static MDB_val kbuf, dbuf;
+
+#ifdef _WIN32
+#define Z	"I"
+#else
+#define Z	"z"
+#endif
+
+#define STRLENOF(s)	(sizeof(s)-1)
+
+typedef struct flagbit {
+	int bit;
+	char *name;
+	int len;
+} flagbit;
+
+#define S(s)	s, STRLENOF(s)
+
+flagbit dbflags[] = {
+	{ MDB_REVERSEKEY, S("reversekey") },
+	{ MDB_DUPSORT, S("dupsort") },
+	{ MDB_INTEGERKEY, S("integerkey") },
+	{ MDB_DUPFIXED, S("dupfixed") },
+	{ MDB_INTEGERDUP, S("integerdup") },
+	{ MDB_REVERSEDUP, S("reversedup") },
+	{ 0, NULL, 0 }
+};
+
+static void readhdr(void)
+{
+	char *ptr;
+
+	while (fgets(dbuf.mv_data, dbuf.mv_size, stdin) != NULL) {
+		lineno++;
+		if (!strncmp(dbuf.mv_data, "VERSION=", STRLENOF("VERSION="))) {
+			version=atoi((char *)dbuf.mv_data+STRLENOF("VERSION="));
+			if (version > 3) {
+				fprintf(stderr, "%s: line %" Z "d: unsupported VERSION %d\n",
+					prog, lineno, version);
+				exit(EXIT_FAILURE);
+			}
+		} else if (!strncmp(dbuf.mv_data, "HEADER=END", STRLENOF("HEADER=END"))) {
+			break;
+		} else if (!strncmp(dbuf.mv_data, "format=", STRLENOF("format="))) {
+			if (!strncmp((char *)dbuf.mv_data+STRLENOF("FORMAT="), "print", STRLENOF("print")))
+				mode |= PRINT;
+			else if (strncmp((char *)dbuf.mv_data+STRLENOF("FORMAT="), "bytevalue", STRLENOF("bytevalue"))) {
+				fprintf(stderr, "%s: line %" Z "d: unsupported FORMAT %s\n",
+					prog, lineno, (char *)dbuf.mv_data+STRLENOF("FORMAT="));
+				exit(EXIT_FAILURE);
+			}
+		} else if (!strncmp(dbuf.mv_data, "database=", STRLENOF("database="))) {
+			ptr = memchr(dbuf.mv_data, '\n', dbuf.mv_size);
+			if (ptr) *ptr = '\0';
+			if (subname) free(subname);
+			subname = strdup((char *)dbuf.mv_data+STRLENOF("database="));
+		} else if (!strncmp(dbuf.mv_data, "type=", STRLENOF("type="))) {
+			if (strncmp((char *)dbuf.mv_data+STRLENOF("type="), "btree", STRLENOF("btree")))  {
+				fprintf(stderr, "%s: line %" Z "d: unsupported type %s\n",
+					prog, lineno, (char *)dbuf.mv_data+STRLENOF("type="));
+				exit(EXIT_FAILURE);
+			}
+		} else if (!strncmp(dbuf.mv_data, "mapaddr=", STRLENOF("mapaddr="))) {
+			int i;
+			ptr = memchr(dbuf.mv_data, '\n', dbuf.mv_size);
+			if (ptr) *ptr = '\0';
+			i = sscanf((char *)dbuf.mv_data+STRLENOF("mapaddr="), "%p", &info.me_mapaddr);
+			if (i != 1) {
+				fprintf(stderr, "%s: line %" Z "d: invalid mapaddr %s\n",
+					prog, lineno, (char *)dbuf.mv_data+STRLENOF("mapaddr="));
+				exit(EXIT_FAILURE);
+			}
+		} else if (!strncmp(dbuf.mv_data, "mapsize=", STRLENOF("mapsize="))) {
+			int i;
+			ptr = memchr(dbuf.mv_data, '\n', dbuf.mv_size);
+			if (ptr) *ptr = '\0';
+			i = sscanf((char *)dbuf.mv_data+STRLENOF("mapsize="), "%" Z "u", &info.me_mapsize);
+			if (i != 1) {
+				fprintf(stderr, "%s: line %" Z "d: invalid mapsize %s\n",
+					prog, lineno, (char *)dbuf.mv_data+STRLENOF("mapsize="));
+				exit(EXIT_FAILURE);
+			}
+		} else if (!strncmp(dbuf.mv_data, "maxreaders=", STRLENOF("maxreaders="))) {
+			int i;
+			ptr = memchr(dbuf.mv_data, '\n', dbuf.mv_size);
+			if (ptr) *ptr = '\0';
+			i = sscanf((char *)dbuf.mv_data+STRLENOF("maxreaders="), "%u", &info.me_maxreaders);
+			if (i != 1) {
+				fprintf(stderr, "%s: line %" Z "d: invalid maxreaders %s\n",
+					prog, lineno, (char *)dbuf.mv_data+STRLENOF("maxreaders="));
+				exit(EXIT_FAILURE);
+			}
+		} else {
+			int i;
+			for (i=0; dbflags[i].bit; i++) {
+				if (!strncmp(dbuf.mv_data, dbflags[i].name, dbflags[i].len) &&
+					((char *)dbuf.mv_data)[dbflags[i].len] == '=') {
+					flags |= dbflags[i].bit;
+					break;
+				}
+			}
+			if (!dbflags[i].bit) {
+				ptr = memchr(dbuf.mv_data, '=', dbuf.mv_size);
+				if (!ptr) {
+					fprintf(stderr, "%s: line %" Z "d: unexpected format\n",
+						prog, lineno);
+					exit(EXIT_FAILURE);
+				} else {
+					*ptr = '\0';
+					fprintf(stderr, "%s: line %" Z "d: unrecognized keyword ignored: %s\n",
+						prog, lineno, (char *)dbuf.mv_data);
+				}
+			}
+		}
+	}
+}
+
+static void badend(void)
+{
+	fprintf(stderr, "%s: line %" Z "d: unexpected end of input\n",
+		prog, lineno);
+}
+
+static int unhex(unsigned char *c2)
+{
+	int x, c;
+	x = *c2++ & 0x4f;
+	if (x & 0x40)
+		x -= 55;
+	c = x << 4;
+	x = *c2 & 0x4f;
+	if (x & 0x40)
+		x -= 55;
+	c |= x;
+	return c;
+}
+
+static int readline(MDB_val *out, MDB_val *buf)
+{
+	unsigned char *c1, *c2, *end;
+	size_t len;
+	int c;
+
+	if (!(mode & NOHDR)) {
+		c = fgetc(stdin);
+		if (c == EOF) {
+			Eof = 1;
+			return EOF;
+		}
+		if (c != ' ') {
+			lineno++;
+			if (fgets(buf->mv_data, buf->mv_size, stdin) == NULL) {
+badend:
+				Eof = 1;
+				badend();
+				return EOF;
+			}
+			if (c == 'D' && !strncmp(buf->mv_data, "ATA=END", STRLENOF("ATA=END")))
+				return EOF;
+			goto badend;
+		}
+	}
+	if (fgets(buf->mv_data, buf->mv_size, stdin) == NULL) {
+		Eof = 1;
+		return EOF;
+	}
+	lineno++;
+
+	c1 = buf->mv_data;
+	len = strlen((char *)c1);
+
+	/* Is buffer too short? */
+	while (c1[len-1] != '\n') {
+		buf->mv_data = realloc(buf->mv_data, buf->mv_size*2);
+		if (!buf->mv_data) {
+			Eof = 1;
+			fprintf(stderr, "%s: line %" Z "d: out of memory, line too long\n",
+				prog, lineno);
+			return EOF;
+		}
+		c1 = buf->mv_data;
+		c1 += buf->mv_size;
+		if (fgets((char *)c1, buf->mv_size, stdin) == NULL) {
+			Eof = 1;
+			badend();
+			return EOF;
+		}
+		buf->mv_size *= 2;
+		len = strlen((char *)c1);
+	}
+	c1 = c2 = buf->mv_data;
+	len = strlen((char *)c1);
+	c1[--len] = '\0';
+	end = c1 + len;
+
+	if (mode & PRINT) {
+		while (c2 < end) {
+			if (*c2 == '\\') {
+				if (c2[1] == '\\') {
+					c1++; c2 += 2;
+				} else {
+					if (c2+3 > end || !isxdigit(c2[1]) || !isxdigit(c2[2])) {
+						Eof = 1;
+						badend();
+						return EOF;
+					}
+					*c1++ = unhex(++c2);
+					c2 += 2;
+				}
+			} else {
+				c1++; c2++;
+			}
+		}
+	} else {
+		/* odd length not allowed */
+		if (len & 1) {
+			Eof = 1;
+			badend();
+			return EOF;
+		}
+		while (c2 < end) {
+			if (!isxdigit(*c2) || !isxdigit(c2[1])) {
+				Eof = 1;
+				badend();
+				return EOF;
+			}
+			*c1++ = unhex(c2);
+			c2 += 2;
+		}
+	}
+	c2 = out->mv_data = buf->mv_data;
+	out->mv_size = c1 - c2;
+
+	return 0;
+}
+
+static void usage(void)
+{
+	fprintf(stderr, "usage: %s dbpath [-V] [-f input] [-n] [-s name] [-N] [-T]\n", prog);
+	exit(EXIT_FAILURE);
+}
+
+int main(int argc, char *argv[])
+{
+	int i, rc;
+	MDB_env *env;
+	MDB_txn *txn;
+	MDB_cursor *mc;
+	MDB_dbi dbi;
+	char *envname;
+	int envflags = 0, putflags = 0;
+	int dohdr = 0;
+
+	prog = argv[0];
+
+	if (argc < 2) {
+		usage();
+	}
+
+	/* -f: load file instead of stdin
+	 * -n: use NOSUBDIR flag on env_open
+	 * -s: load into named subDB
+	 * -N: use NOOVERWRITE on puts
+	 * -T: read plaintext
+	 * -V: print version and exit
+	 */
+	while ((i = getopt(argc, argv, "f:ns:NTV")) != EOF) {
+		switch(i) {
+		case 'V':
+			printf("%s\n", MDB_VERSION_STRING);
+			exit(0);
+			break;
+		case 'f':
+			if (freopen(optarg, "r", stdin) == NULL) {
+				fprintf(stderr, "%s: %s: reopen: %s\n",
+					prog, optarg, strerror(errno));
+				exit(EXIT_FAILURE);
+			}
+			break;
+		case 'n':
+			envflags |= MDB_NOSUBDIR;
+			break;
+		case 's':
+			subname = strdup(optarg);
+			break;
+		case 'N':
+			putflags = MDB_NOOVERWRITE|MDB_NODUPDATA;
+			break;
+		case 'T':
+			mode |= NOHDR;
+			break;
+		default:
+			usage();
+		}
+	}
+
+	if (optind != argc - 1)
+		usage();
+
+	dbuf.mv_size = 4096;
+	dbuf.mv_data = malloc(dbuf.mv_size);
+
+	if (!(mode & NOHDR))
+		readhdr();
+
+	envname = argv[optind];
+	rc = mdb_env_create(&env);
+	if (rc) {
+		fprintf(stderr, "mdb_env_create failed, error %d %s\n", rc, mdb_strerror(rc));
+		return EXIT_FAILURE;
+	}
+
+	mdb_env_set_maxdbs(env, 2);
+
+	if (info.me_maxreaders)
+		mdb_env_set_maxreaders(env, info.me_maxreaders);
+
+	if (info.me_mapsize)
+		mdb_env_set_mapsize(env, info.me_mapsize);
+
+	if (info.me_mapaddr)
+		envflags |= MDB_FIXEDMAP;
+
+	rc = mdb_env_open(env, envname, envflags, 0664);
+	if (rc) {
+		fprintf(stderr, "mdb_env_open failed, error %d %s\n", rc, mdb_strerror(rc));
+		goto env_close;
+	}
+
+	kbuf.mv_size = mdb_env_get_maxkeysize(env) * 2 + 2;
+	kbuf.mv_data = malloc(kbuf.mv_size);
+
+	while(!Eof) {
+		MDB_val key, data;
+		int batch = 0;
+		flags = 0;
+
+		if (!dohdr) {
+			dohdr = 1;
+		} else if (!(mode & NOHDR))
+			readhdr();
+		
+		rc = mdb_txn_begin(env, NULL, 0, &txn);
+		if (rc) {
+			fprintf(stderr, "mdb_txn_begin failed, error %d %s\n", rc, mdb_strerror(rc));
+			goto env_close;
+		}
+
+		rc = mdb_open(txn, subname, flags|MDB_CREATE, &dbi);
+		if (rc) {
+			fprintf(stderr, "mdb_open failed, error %d %s\n", rc, mdb_strerror(rc));
+			goto txn_abort;
+		}
+
+		rc = mdb_cursor_open(txn, dbi, &mc);
+		if (rc) {
+			fprintf(stderr, "mdb_cursor_open failed, error %d %s\n", rc, mdb_strerror(rc));
+			goto txn_abort;
+		}
+
+		while(1) {
+			rc = readline(&key, &kbuf);
+			if (rc == EOF)
+				break;
+			if (rc)
+				goto txn_abort;
+
+			rc = readline(&data, &dbuf);
+			if (rc)
+				goto txn_abort;
+			
+			rc = mdb_cursor_put(mc, &key, &data, putflags);
+			if (rc == MDB_KEYEXIST && putflags)
+				continue;
+			if (rc)
+				goto txn_abort;
+			batch++;
+			if (batch == 100) {
+				rc = mdb_txn_commit(txn);
+				if (rc) {
+					fprintf(stderr, "%s: line %" Z "d: txn_commit: %s\n",
+						prog, lineno, mdb_strerror(rc));
+					goto env_close;
+				}
+				rc = mdb_txn_begin(env, NULL, 0, &txn);
+				if (rc) {
+					fprintf(stderr, "mdb_txn_begin failed, error %d %s\n", rc, mdb_strerror(rc));
+					goto env_close;
+				}
+				rc = mdb_cursor_open(txn, dbi, &mc);
+				if (rc) {
+					fprintf(stderr, "mdb_cursor_open failed, error %d %s\n", rc, mdb_strerror(rc));
+					goto txn_abort;
+				}
+				batch = 0;
+			}
+		}
+		rc = mdb_txn_commit(txn);
+		txn = NULL;
+		if (rc) {
+			fprintf(stderr, "%s: line %" Z "d: txn_commit: %s\n",
+				prog, lineno, mdb_strerror(rc));
+			goto env_close;
+		}
+		mdb_dbi_close(env, dbi);
+	}
+
+txn_abort:
+	mdb_txn_abort(txn);
+env_close:
+	mdb_env_close(env);
+
+	return rc ? EXIT_FAILURE : EXIT_SUCCESS;
+}
diff --git a/external/db_drivers/liblmdb64/mdb_stat.1 b/external/db_drivers/liblmdb64/mdb_stat.1
new file mode 100644
index 000000000..3d8d461d9
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mdb_stat.1
@@ -0,0 +1,64 @@
+.TH MDB_STAT 1 "2014/06/20" "LMDB 0.9.14"
+.\" Copyright 2012-2014 Howard Chu, Symas Corp. All Rights Reserved.
+.\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
+.SH NAME
+mdb_stat \- LMDB environment status tool
+.SH SYNOPSIS
+.B mdb_stat
+.BR \ envpath
+[\c
+.BR \-V ]
+[\c
+.BR \-e ]
+[\c
+.BR \-f [ f [ f ]]]
+[\c
+.BR \-n ]
+[\c
+.BR \-r [ r ]]
+[\c
+.BR \-a \ |
+.BI \-s \ subdb\fR]
+.SH DESCRIPTION
+The
+.B mdb_stat
+utility displays the status of an LMDB environment.
+.SH OPTIONS
+.TP
+.BR \-V
+Write the library version number to the standard output, and exit.
+.TP
+.BR \-e
+Display information about the database environment.
+.TP
+.BR \-f
+Display information about the environment freelist.
+If \fB\-ff\fP is given, summarize each freelist entry.
+If \fB\-fff\fP is given, display the full list of page IDs in the freelist.
+.TP
+.BR \-n
+Display the status of an LMDB database which does not use subdirectories.
+.TP
+.BR \-r
+Display information about the environment reader table.
+Shows the process ID, thread ID, and transaction ID for each active
+reader slot. The process ID and transaction ID are in decimal, the
+thread ID is in hexadecimal. The transaction ID is displayed as "-"
+if the reader does not currently have a read transaction open.
+If \fB\-rr\fP is given, check for stale entries in the reader
+table and clear them. The reader table will be printed again
+after the check is performed.
+.TP
+.BR \-a
+Display the status of all of the subdatabases in the environment.
+.TP
+.BR \-s \ subdb
+Display the status of a specific subdatabase.
+.SH DIAGNOSTICS
+Exit status is zero if no errors occur.
+Errors result in a non-zero exit status and
+a diagnostic message being written to standard error.
+.SH "SEE ALSO"
+.BR mdb_copy (1)
+.SH AUTHOR
+Howard Chu of Symas Corporation <http://www.symas.com>
diff --git a/external/db_drivers/liblmdb64/mdb_stat.c b/external/db_drivers/liblmdb64/mdb_stat.c
new file mode 100644
index 000000000..1e9229296
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mdb_stat.c
@@ -0,0 +1,263 @@
+/* mdb_stat.c - memory-mapped database status tool */
+/*
+ * Copyright 2011-2013 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "lmdb.h"
+
+#ifdef	_WIN32
+#define	Z	"I"
+#else
+#define	Z	"z"
+#endif
+
+static void prstat(MDB_stat *ms)
+{
+#if 0
+	printf("  Page size: %u\n", ms->ms_psize);
+#endif
+	printf("  Tree depth: %u\n", ms->ms_depth);
+	printf("  Branch pages: %"Z"u\n", ms->ms_branch_pages);
+	printf("  Leaf pages: %"Z"u\n", ms->ms_leaf_pages);
+	printf("  Overflow pages: %"Z"u\n", ms->ms_overflow_pages);
+	printf("  Entries: %"Z"u\n", ms->ms_entries);
+}
+
+static void usage(char *prog)
+{
+	fprintf(stderr, "usage: %s dbpath [-V] [-n] [-e] [-r[r]] [-f[f[f]]] [-a|-s subdb]\n", prog);
+	exit(EXIT_FAILURE);
+}
+
+int main(int argc, char *argv[])
+{
+	int i, rc;
+	MDB_env *env;
+	MDB_txn *txn;
+	MDB_dbi dbi;
+	MDB_stat mst;
+	MDB_envinfo mei;
+	char *prog = argv[0];
+	char *envname;
+	char *subname = NULL;
+	int alldbs = 0, envinfo = 0, envflags = 0, freinfo = 0, rdrinfo = 0;
+
+	if (argc < 2) {
+		usage(prog);
+	}
+
+	/* -a: print stat of main DB and all subDBs
+	 * -s: print stat of only the named subDB
+	 * -e: print env info
+	 * -f: print freelist info
+	 * -r: print reader info
+	 * -n: use NOSUBDIR flag on env_open
+	 * -V: print version and exit
+	 * (default) print stat of only the main DB
+	 */
+	while ((i = getopt(argc, argv, "Vaefnrs:")) != EOF) {
+		switch(i) {
+		case 'V':
+			printf("%s\n", MDB_VERSION_STRING);
+			exit(0);
+			break;
+		case 'a':
+			if (subname)
+				usage(prog);
+			alldbs++;
+			break;
+		case 'e':
+			envinfo++;
+			break;
+		case 'f':
+			freinfo++;
+			break;
+		case 'n':
+			envflags |= MDB_NOSUBDIR;
+			break;
+		case 'r':
+			rdrinfo++;
+			break;
+		case 's':
+			if (alldbs)
+				usage(prog);
+			subname = optarg;
+			break;
+		default:
+			usage(prog);
+		}
+	}
+
+	if (optind != argc - 1)
+		usage(prog);
+
+	envname = argv[optind];
+	rc = mdb_env_create(&env);
+	if (rc) {
+		fprintf(stderr, "mdb_env_create failed, error %d %s\n", rc, mdb_strerror(rc));
+		return EXIT_FAILURE;
+	}
+
+	if (alldbs || subname) {
+		mdb_env_set_maxdbs(env, 4);
+	}
+
+	rc = mdb_env_open(env, envname, envflags | MDB_RDONLY, 0664);
+	if (rc) {
+		fprintf(stderr, "mdb_env_open failed, error %d %s\n", rc, mdb_strerror(rc));
+		goto env_close;
+	}
+
+	if (envinfo) {
+		(void)mdb_env_stat(env, &mst);
+		(void)mdb_env_info(env, &mei);
+		printf("Environment Info\n");
+		printf("  Map address: %p\n", mei.me_mapaddr);
+		printf("  Map size: %"Z"u\n", mei.me_mapsize);
+		printf("  Page size: %u\n", mst.ms_psize);
+		printf("  Max pages: %"Z"u\n", mei.me_mapsize / mst.ms_psize);
+		printf("  Number of pages used: %"Z"u\n", mei.me_last_pgno+1);
+		printf("  Last transaction ID: %"Z"u\n", mei.me_last_txnid);
+		printf("  Max readers: %u\n", mei.me_maxreaders);
+		printf("  Number of readers used: %u\n", mei.me_numreaders);
+	}
+
+	if (rdrinfo) {
+		printf("Reader Table Status\n");
+		rc = mdb_reader_list(env, (MDB_msg_func *)fputs, stdout);
+		if (rdrinfo > 1) {
+			int dead;
+			mdb_reader_check(env, &dead);
+			printf("  %d stale readers cleared.\n", dead);
+			rc = mdb_reader_list(env, (MDB_msg_func *)fputs, stdout);
+		}
+		if (!(subname || alldbs || freinfo))
+			goto env_close;
+	}
+
+	rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
+	if (rc) {
+		fprintf(stderr, "mdb_txn_begin failed, error %d %s\n", rc, mdb_strerror(rc));
+		goto env_close;
+	}
+
+	if (freinfo) {
+		MDB_cursor *cursor;
+		MDB_val key, data;
+		size_t pages = 0, *iptr;
+
+		printf("Freelist Status\n");
+		dbi = 0;
+		rc = mdb_cursor_open(txn, dbi, &cursor);
+		if (rc) {
+			fprintf(stderr, "mdb_cursor_open failed, error %d %s\n", rc, mdb_strerror(rc));
+			goto txn_abort;
+		}
+		rc = mdb_stat(txn, dbi, &mst);
+		if (rc) {
+			fprintf(stderr, "mdb_stat failed, error %d %s\n", rc, mdb_strerror(rc));
+			goto txn_abort;
+		}
+		prstat(&mst);
+		while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+			iptr = data.mv_data;
+			pages += *iptr;
+			if (freinfo > 1) {
+				char *bad = "";
+				size_t pg, prev;
+				ssize_t i, j, span = 0;
+				j = *iptr++;
+				for (i = j, prev = 1; --i >= 0; ) {
+					pg = iptr[i];
+					if (pg <= prev)
+						bad = " [bad sequence]";
+					prev = pg;
+					pg += span;
+					for (; i >= span && iptr[i-span] == pg; span++, pg++) ;
+				}
+				printf("    Transaction %"Z"u, %"Z"d pages, maxspan %"Z"d%s\n",
+					*(size_t *)key.mv_data, j, span, bad);
+				if (freinfo > 2) {
+					for (--j; j >= 0; ) {
+						pg = iptr[j];
+						for (span=1; --j >= 0 && iptr[j] == pg+span; span++) ;
+						printf(span>1 ? "     %9"Z"u[%"Z"d]\n" : "     %9"Z"u\n",
+							pg, span);
+					}
+				}
+			}
+		}
+		mdb_cursor_close(cursor);
+		printf("  Free pages: %"Z"u\n", pages);
+	}
+
+	rc = mdb_open(txn, subname, 0, &dbi);
+	if (rc) {
+		fprintf(stderr, "mdb_open failed, error %d %s\n", rc, mdb_strerror(rc));
+		goto txn_abort;
+	}
+
+	rc = mdb_stat(txn, dbi, &mst);
+	if (rc) {
+		fprintf(stderr, "mdb_stat failed, error %d %s\n", rc, mdb_strerror(rc));
+		goto txn_abort;
+	}
+	printf("Status of %s\n", subname ? subname : "Main DB");
+	prstat(&mst);
+
+	if (alldbs) {
+		MDB_cursor *cursor;
+		MDB_val key;
+
+		rc = mdb_cursor_open(txn, dbi, &cursor);
+		if (rc) {
+			fprintf(stderr, "mdb_cursor_open failed, error %d %s\n", rc, mdb_strerror(rc));
+			goto txn_abort;
+		}
+		while ((rc = mdb_cursor_get(cursor, &key, NULL, MDB_NEXT_NODUP)) == 0) {
+			char *str;
+			MDB_dbi db2;
+			if (memchr(key.mv_data, '\0', key.mv_size))
+				continue;
+			str = malloc(key.mv_size+1);
+			memcpy(str, key.mv_data, key.mv_size);
+			str[key.mv_size] = '\0';
+			rc = mdb_open(txn, str, 0, &db2);
+			if (rc == MDB_SUCCESS)
+				printf("Status of %s\n", str);
+			free(str);
+			if (rc) continue;
+			rc = mdb_stat(txn, db2, &mst);
+			if (rc) {
+				fprintf(stderr, "mdb_stat failed, error %d %s\n", rc, mdb_strerror(rc));
+				goto txn_abort;
+			}
+			prstat(&mst);
+			mdb_close(env, db2);
+		}
+		mdb_cursor_close(cursor);
+	}
+
+	if (rc == MDB_NOTFOUND)
+		rc = MDB_SUCCESS;
+
+	mdb_close(env, dbi);
+txn_abort:
+	mdb_txn_abort(txn);
+env_close:
+	mdb_env_close(env);
+
+	return rc ? EXIT_FAILURE : EXIT_SUCCESS;
+}
diff --git a/external/db_drivers/liblmdb64/midl.c b/external/db_drivers/liblmdb64/midl.c
new file mode 100644
index 000000000..88a3aff10
--- /dev/null
+++ b/external/db_drivers/liblmdb64/midl.c
@@ -0,0 +1,360 @@
+/**	@file midl.c
+ *	@brief ldap bdb back-end ID List functions */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2000-2014 The OpenLDAP Foundation.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+#include <limits.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+#include "midl.h"
+
+/** @defgroup internal	LMDB Internals
+ *	@{
+ */
+/** @defgroup idls	ID List Management
+ *	@{
+ */
+#define CMP(x,y)	 ( (x) < (y) ? -1 : (x) > (y) )
+
+unsigned mdb_midl_search( MDB_IDL ids, MDB_ID id )
+{
+	/*
+	 * binary search of id in ids
+	 * if found, returns position of id
+	 * if not found, returns first position greater than id
+	 */
+	unsigned base = 0;
+	unsigned cursor = 1;
+	int val = 0;
+	unsigned n = ids[0];
+
+	while( 0 < n ) {
+		unsigned pivot = n >> 1;
+		cursor = base + pivot + 1;
+		val = CMP( ids[cursor], id );
+
+		if( val < 0 ) {
+			n = pivot;
+
+		} else if ( val > 0 ) {
+			base = cursor;
+			n -= pivot + 1;
+
+		} else {
+			return cursor;
+		}
+	}
+
+	if( val > 0 ) {
+		++cursor;
+	}
+	return cursor;
+}
+
+#if 0	/* superseded by append/sort */
+int mdb_midl_insert( MDB_IDL ids, MDB_ID id )
+{
+	unsigned x, i;
+
+	x = mdb_midl_search( ids, id );
+	assert( x > 0 );
+
+	if( x < 1 ) {
+		/* internal error */
+		return -2;
+	}
+
+	if ( x <= ids[0] && ids[x] == id ) {
+		/* duplicate */
+		assert(0);
+		return -1;
+	}
+
+	if ( ++ids[0] >= MDB_IDL_DB_MAX ) {
+		/* no room */
+		--ids[0];
+		return -2;
+
+	} else {
+		/* insert id */
+		for (i=ids[0]; i>x; i--)
+			ids[i] = ids[i-1];
+		ids[x] = id;
+	}
+
+	return 0;
+}
+#endif
+
+MDB_IDL mdb_midl_alloc(int num)
+{
+	MDB_IDL ids = malloc((num+2) * sizeof(MDB_ID));
+	if (ids) {
+		*ids++ = num;
+		*ids = 0;
+	}
+	return ids;
+}
+
+void mdb_midl_free(MDB_IDL ids)
+{
+	if (ids)
+		free(ids-1);
+}
+
+int mdb_midl_shrink( MDB_IDL *idp )
+{
+	MDB_IDL ids = *idp;
+	if (*(--ids) > MDB_IDL_UM_MAX &&
+		(ids = realloc(ids, (MDB_IDL_UM_MAX+1) * sizeof(MDB_ID))))
+	{
+		*ids++ = MDB_IDL_UM_MAX;
+		*idp = ids;
+		return 1;
+	}
+	return 0;
+}
+
+static int mdb_midl_grow( MDB_IDL *idp, int num )
+{
+	MDB_IDL idn = *idp-1;
+	/* grow it */
+	idn = realloc(idn, (*idn + num + 2) * sizeof(MDB_ID));
+	if (!idn)
+		return ENOMEM;
+	*idn++ += num;
+	*idp = idn;
+	return 0;
+}
+
+int mdb_midl_need( MDB_IDL *idp, unsigned num )
+{
+	MDB_IDL ids = *idp;
+	num += ids[0];
+	if (num > ids[-1]) {
+		num = (num + num/4 + (256 + 2)) & -256;
+		if (!(ids = realloc(ids-1, num * sizeof(MDB_ID))))
+			return ENOMEM;
+		*ids++ = num - 2;
+		*idp = ids;
+	}
+	return 0;
+}
+
+int mdb_midl_append( MDB_IDL *idp, MDB_ID id )
+{
+	MDB_IDL ids = *idp;
+	/* Too big? */
+	if (ids[0] >= ids[-1]) {
+		if (mdb_midl_grow(idp, MDB_IDL_UM_MAX))
+			return ENOMEM;
+		ids = *idp;
+	}
+	ids[0]++;
+	ids[ids[0]] = id;
+	return 0;
+}
+
+int mdb_midl_append_list( MDB_IDL *idp, MDB_IDL app )
+{
+	MDB_IDL ids = *idp;
+	/* Too big? */
+	if (ids[0] + app[0] >= ids[-1]) {
+		if (mdb_midl_grow(idp, app[0]))
+			return ENOMEM;
+		ids = *idp;
+	}
+	memcpy(&ids[ids[0]+1], &app[1], app[0] * sizeof(MDB_ID));
+	ids[0] += app[0];
+	return 0;
+}
+
+int mdb_midl_append_range( MDB_IDL *idp, MDB_ID id, unsigned n )
+{
+	MDB_ID *ids = *idp, len = ids[0];
+	/* Too big? */
+	if (len + n > ids[-1]) {
+		if (mdb_midl_grow(idp, n | MDB_IDL_UM_MAX))
+			return ENOMEM;
+		ids = *idp;
+	}
+	ids[0] = len + n;
+	ids += len;
+	while (n)
+		ids[n--] = id++;
+	return 0;
+}
+
+void mdb_midl_xmerge( MDB_IDL idl, MDB_IDL merge )
+{
+	MDB_ID old_id, merge_id, i = merge[0], j = idl[0], k = i+j, total = k;
+	idl[0] = (MDB_ID)-1;		/* delimiter for idl scan below */
+	old_id = idl[j];
+	while (i) {
+		merge_id = merge[i--];
+		for (; old_id < merge_id; old_id = idl[--j])
+			idl[k--] = old_id;
+		idl[k--] = merge_id;
+	}
+	idl[0] = total;
+}
+
+/* Quicksort + Insertion sort for small arrays */
+
+#define SMALL	8
+#define	MIDL_SWAP(a,b)	{ itmp=(a); (a)=(b); (b)=itmp; }
+
+void
+mdb_midl_sort( MDB_IDL ids )
+{
+	/* Max possible depth of int-indexed tree * 2 items/level */
+	int istack[sizeof(int)*CHAR_BIT * 2];
+	int i,j,k,l,ir,jstack;
+	MDB_ID a, itmp;
+
+	ir = (int)ids[0];
+	l = 1;
+	jstack = 0;
+	for(;;) {
+		if (ir - l < SMALL) {	/* Insertion sort */
+			for (j=l+1;j<=ir;j++) {
+				a = ids[j];
+				for (i=j-1;i>=1;i--) {
+					if (ids[i] >= a) break;
+					ids[i+1] = ids[i];
+				}
+				ids[i+1] = a;
+			}
+			if (jstack == 0) break;
+			ir = istack[jstack--];
+			l = istack[jstack--];
+		} else {
+			k = (l + ir) >> 1;	/* Choose median of left, center, right */
+			MIDL_SWAP(ids[k], ids[l+1]);
+			if (ids[l] < ids[ir]) {
+				MIDL_SWAP(ids[l], ids[ir]);
+			}
+			if (ids[l+1] < ids[ir]) {
+				MIDL_SWAP(ids[l+1], ids[ir]);
+			}
+			if (ids[l] < ids[l+1]) {
+				MIDL_SWAP(ids[l], ids[l+1]);
+			}
+			i = l+1;
+			j = ir;
+			a = ids[l+1];
+			for(;;) {
+				do i++; while(ids[i] > a);
+				do j--; while(ids[j] < a);
+				if (j < i) break;
+				MIDL_SWAP(ids[i],ids[j]);
+			}
+			ids[l+1] = ids[j];
+			ids[j] = a;
+			jstack += 2;
+			if (ir-i+1 >= j-l) {
+				istack[jstack] = ir;
+				istack[jstack-1] = i;
+				ir = j-1;
+			} else {
+				istack[jstack] = j-1;
+				istack[jstack-1] = l;
+				l = i;
+			}
+		}
+	}
+}
+
+unsigned mdb_mid2l_search( MDB_ID2L ids, MDB_ID id )
+{
+	/*
+	 * binary search of id in ids
+	 * if found, returns position of id
+	 * if not found, returns first position greater than id
+	 */
+	unsigned base = 0;
+	unsigned cursor = 1;
+	int val = 0;
+	unsigned n = (unsigned)ids[0].mid;
+
+	while( 0 < n ) {
+		unsigned pivot = n >> 1;
+		cursor = base + pivot + 1;
+		val = CMP( id, ids[cursor].mid );
+
+		if( val < 0 ) {
+			n = pivot;
+
+		} else if ( val > 0 ) {
+			base = cursor;
+			n -= pivot + 1;
+
+		} else {
+			return cursor;
+		}
+	}
+
+	if( val > 0 ) {
+		++cursor;
+	}
+	return cursor;
+}
+
+int mdb_mid2l_insert( MDB_ID2L ids, MDB_ID2 *id )
+{
+	unsigned x, i;
+
+	x = mdb_mid2l_search( ids, id->mid );
+
+	if( x < 1 ) {
+		/* internal error */
+		return -2;
+	}
+
+	if ( x <= ids[0].mid && ids[x].mid == id->mid ) {
+		/* duplicate */
+		return -1;
+	}
+
+	if ( ids[0].mid >= MDB_IDL_UM_MAX ) {
+		/* too big */
+		return -2;
+
+	} else {
+		/* insert id */
+		ids[0].mid++;
+		for (i=(unsigned)ids[0].mid; i>x; i--)
+			ids[i] = ids[i-1];
+		ids[x] = *id;
+	}
+
+	return 0;
+}
+
+int mdb_mid2l_append( MDB_ID2L ids, MDB_ID2 *id )
+{
+	/* Too big? */
+	if (ids[0].mid >= MDB_IDL_UM_MAX) {
+		return -2;
+	}
+	ids[0].mid++;
+	ids[ids[0].mid] = *id;
+	return 0;
+}
+
+/** @} */
+/** @} */
diff --git a/external/db_drivers/liblmdb/midl.h b/external/db_drivers/liblmdb64/midl.h
index a7f25026c..a7f25026c 100644
--- a/external/db_drivers/liblmdb/midl.h
+++ b/external/db_drivers/liblmdb64/midl.h
diff --git a/external/db_drivers/liblmdb/mtest.c b/external/db_drivers/liblmdb64/mtest.c
index 79b4175e7..79b4175e7 100644
--- a/external/db_drivers/liblmdb/mtest.c
+++ b/external/db_drivers/liblmdb64/mtest.c
diff --git a/external/db_drivers/liblmdb64/mtest2.c b/external/db_drivers/liblmdb64/mtest2.c
new file mode 100644
index 000000000..f1a3dbd6c
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mtest2.c
@@ -0,0 +1,123 @@
+/* mtest2.c - memory-mapped database tester/toy */
+/*
+ * Copyright 2011-2014 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+/* Just like mtest.c, but using a subDB instead of the main DB */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include "lmdb.h"
+
+#define E(expr) CHECK((rc = (expr)) == MDB_SUCCESS, #expr)
+#define RES(err, expr) ((rc = expr) == (err) || (CHECK(!rc, #expr), 0))
+#define CHECK(test, msg) ((test) ? (void)0 : ((void)fprintf(stderr, \
+	"%s:%d: %s: %s\n", __FILE__, __LINE__, msg, mdb_strerror(rc)), abort()))
+
+int main(int argc,char * argv[])
+{
+	int i = 0, j = 0, rc;
+	MDB_env *env;
+	MDB_dbi dbi;
+	MDB_val key, data;
+	MDB_txn *txn;
+	MDB_stat mst;
+	MDB_cursor *cursor;
+	int count;
+	int *values;
+	char sval[32] = "";
+
+	srand(time(NULL));
+
+	count = (rand()%384) + 64;
+	values = (int *)malloc(count*sizeof(int));
+
+	for(i = 0;i<count;i++) {
+		values[i] = rand()%1024;
+	}
+
+	E(mdb_env_create(&env));
+	E(mdb_env_set_mapsize(env, 10485760));
+	E(mdb_env_set_maxdbs(env, 4));
+	E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP|MDB_NOSYNC, 0664));
+	E(mdb_txn_begin(env, NULL, 0, &txn));
+	E(mdb_open(txn, "id1", MDB_CREATE, &dbi));
+   
+	key.mv_size = sizeof(int);
+	key.mv_data = sval;
+	data.mv_size = sizeof(sval);
+	data.mv_data = sval;
+
+	printf("Adding %d values\n", count);
+	for (i=0;i<count;i++) {	
+		sprintf(sval, "%03x %d foo bar", values[i], values[i]);
+		if (RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NOOVERWRITE)))
+			j++;
+	}
+	if (j) printf("%d duplicates skipped\n", j);
+	E(mdb_txn_commit(txn));
+	E(mdb_env_stat(env, &mst));
+
+	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+		printf("key: %p %.*s, data: %p %.*s\n",
+			key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
+			data.mv_data, (int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	mdb_cursor_close(cursor);
+	mdb_txn_abort(txn);
+
+	j=0;
+	key.mv_data = sval;
+	for (i= count - 1; i > -1; i-= (rand()%5)) {
+		j++;
+		txn=NULL;
+		E(mdb_txn_begin(env, NULL, 0, &txn));
+		sprintf(sval, "%03x ", values[i]);
+		if (RES(MDB_NOTFOUND, mdb_del(txn, dbi, &key, NULL))) {
+			j--;
+			mdb_txn_abort(txn);
+		} else {
+			E(mdb_txn_commit(txn));
+		}
+	}
+	free(values);
+	printf("Deleted %d values\n", j);
+
+	E(mdb_env_stat(env, &mst));
+	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+	printf("Cursor next\n");
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	printf("Cursor prev\n");
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_PREV)) == 0) {
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	mdb_cursor_close(cursor);
+	mdb_close(env, dbi);
+
+	mdb_txn_abort(txn);
+	mdb_env_close(env);
+
+	return 0;
+}
diff --git a/external/db_drivers/liblmdb64/mtest3.c b/external/db_drivers/liblmdb64/mtest3.c
new file mode 100644
index 000000000..f705c52de
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mtest3.c
@@ -0,0 +1,133 @@
+/* mtest3.c - memory-mapped database tester/toy */
+/*
+ * Copyright 2011-2014 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+/* Tests for sorted duplicate DBs */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include "lmdb.h"
+
+#define E(expr) CHECK((rc = (expr)) == MDB_SUCCESS, #expr)
+#define RES(err, expr) ((rc = expr) == (err) || (CHECK(!rc, #expr), 0))
+#define CHECK(test, msg) ((test) ? (void)0 : ((void)fprintf(stderr, \
+	"%s:%d: %s: %s\n", __FILE__, __LINE__, msg, mdb_strerror(rc)), abort()))
+
+int main(int argc,char * argv[])
+{
+	int i = 0, j = 0, rc;
+	MDB_env *env;
+	MDB_dbi dbi;
+	MDB_val key, data;
+	MDB_txn *txn;
+	MDB_stat mst;
+	MDB_cursor *cursor;
+	int count;
+	int *values;
+	char sval[32];
+	char kval[sizeof(int)];
+
+	srand(time(NULL));
+
+	memset(sval, 0, sizeof(sval));
+
+	count = (rand()%384) + 64;
+	values = (int *)malloc(count*sizeof(int));
+
+	for(i = 0;i<count;i++) {
+		values[i] = rand()%1024;
+	}
+
+	E(mdb_env_create(&env));
+	E(mdb_env_set_mapsize(env, 10485760));
+	E(mdb_env_set_maxdbs(env, 4));
+	E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP|MDB_NOSYNC, 0664));
+	E(mdb_txn_begin(env, NULL, 0, &txn));
+	E(mdb_open(txn, "id2", MDB_CREATE|MDB_DUPSORT, &dbi));
+
+	key.mv_size = sizeof(int);
+	key.mv_data = kval;
+	data.mv_size = sizeof(sval);
+	data.mv_data = sval;
+
+	printf("Adding %d values\n", count);
+	for (i=0;i<count;i++) {
+		if (!(i & 0x0f))
+			sprintf(kval, "%03x", values[i]);
+		sprintf(sval, "%03x %d foo bar", values[i], values[i]);
+		if (RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NODUPDATA)))
+			j++;
+	}
+	if (j) printf("%d duplicates skipped\n", j);
+	E(mdb_txn_commit(txn));
+	E(mdb_env_stat(env, &mst));
+
+	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+		printf("key: %p %.*s, data: %p %.*s\n",
+			key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
+			data.mv_data, (int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	mdb_cursor_close(cursor);
+	mdb_txn_abort(txn);
+
+	j=0;
+
+	for (i= count - 1; i > -1; i-= (rand()%5)) {
+		j++;
+		txn=NULL;
+		E(mdb_txn_begin(env, NULL, 0, &txn));
+		sprintf(kval, "%03x", values[i & ~0x0f]);
+		sprintf(sval, "%03x %d foo bar", values[i], values[i]);
+		key.mv_size = sizeof(int);
+		key.mv_data = kval;
+		data.mv_size = sizeof(sval);
+		data.mv_data = sval;
+		if (RES(MDB_NOTFOUND, mdb_del(txn, dbi, &key, &data))) {
+			j--;
+			mdb_txn_abort(txn);
+		} else {
+			E(mdb_txn_commit(txn));
+		}
+	}
+	free(values);
+	printf("Deleted %d values\n", j);
+
+	E(mdb_env_stat(env, &mst));
+	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+	printf("Cursor next\n");
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	printf("Cursor prev\n");
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_PREV)) == 0) {
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	mdb_cursor_close(cursor);
+	mdb_close(env, dbi);
+
+	mdb_txn_abort(txn);
+	mdb_env_close(env);
+
+	return 0;
+}
diff --git a/external/db_drivers/liblmdb64/mtest4.c b/external/db_drivers/liblmdb64/mtest4.c
new file mode 100644
index 000000000..da5a95304
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mtest4.c
@@ -0,0 +1,168 @@
+/* mtest4.c - memory-mapped database tester/toy */
+/*
+ * Copyright 2011-2014 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+/* Tests for sorted duplicate DBs with fixed-size keys */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include "lmdb.h"
+
+#define E(expr) CHECK((rc = (expr)) == MDB_SUCCESS, #expr)
+#define RES(err, expr) ((rc = expr) == (err) || (CHECK(!rc, #expr), 0))
+#define CHECK(test, msg) ((test) ? (void)0 : ((void)fprintf(stderr, \
+	"%s:%d: %s: %s\n", __FILE__, __LINE__, msg, mdb_strerror(rc)), abort()))
+
+int main(int argc,char * argv[])
+{
+	int i = 0, j = 0, rc;
+	MDB_env *env;
+	MDB_dbi dbi;
+	MDB_val key, data;
+	MDB_txn *txn;
+	MDB_stat mst;
+	MDB_cursor *cursor;
+	int count;
+	int *values;
+	char sval[8];
+	char kval[sizeof(int)];
+
+	memset(sval, 0, sizeof(sval));
+
+	count = 510;
+	values = (int *)malloc(count*sizeof(int));
+
+	for(i = 0;i<count;i++) {
+		values[i] = i*5;
+	}
+
+	E(mdb_env_create(&env));
+	E(mdb_env_set_mapsize(env, 10485760));
+	E(mdb_env_set_maxdbs(env, 4));
+	E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP|MDB_NOSYNC, 0664));
+	E(mdb_txn_begin(env, NULL, 0, &txn));
+	E(mdb_open(txn, "id4", MDB_CREATE|MDB_DUPSORT|MDB_DUPFIXED, &dbi));
+
+	key.mv_size = sizeof(int);
+	key.mv_data = kval;
+	data.mv_size = sizeof(sval);
+	data.mv_data = sval;
+
+	printf("Adding %d values\n", count);
+	strcpy(kval, "001");
+	for (i=0;i<count;i++) {
+		sprintf(sval, "%07x", values[i]);
+		if (RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NODUPDATA)))
+			j++;
+	}
+	if (j) printf("%d duplicates skipped\n", j);
+	E(mdb_txn_commit(txn));
+	E(mdb_env_stat(env, &mst));
+
+	/* there should be one full page of dups now.
+	 */
+	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+		printf("key: %p %.*s, data: %p %.*s\n",
+			key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
+			data.mv_data, (int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	mdb_cursor_close(cursor);
+	mdb_txn_abort(txn);
+
+	/* test all 3 branches of split code:
+	 * 1: new key in lower half
+	 * 2: new key at split point
+	 * 3: new key in upper half
+	 */
+
+	key.mv_size = sizeof(int);
+	key.mv_data = kval;
+	data.mv_size = sizeof(sval);
+	data.mv_data = sval;
+
+	sprintf(sval, "%07x", values[3]+1);
+	E(mdb_txn_begin(env, NULL, 0, &txn));
+	(void)RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NODUPDATA));
+	mdb_txn_abort(txn);
+
+	sprintf(sval, "%07x", values[255]+1);
+	E(mdb_txn_begin(env, NULL, 0, &txn));
+	(void)RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NODUPDATA));
+	mdb_txn_abort(txn);
+
+	sprintf(sval, "%07x", values[500]+1);
+	E(mdb_txn_begin(env, NULL, 0, &txn));
+	(void)RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NODUPDATA));
+	E(mdb_txn_commit(txn));
+
+	/* Try MDB_NEXT_MULTIPLE */
+	E(mdb_txn_begin(env, NULL, 0, &txn));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT_MULTIPLE)) == 0) {
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	mdb_cursor_close(cursor);
+	mdb_txn_abort(txn);
+	j=0;
+
+	for (i= count - 1; i > -1; i-= (rand()%3)) {
+		j++;
+		txn=NULL;
+		E(mdb_txn_begin(env, NULL, 0, &txn));
+		sprintf(sval, "%07x", values[i]);
+		key.mv_size = sizeof(int);
+		key.mv_data = kval;
+		data.mv_size = sizeof(sval);
+		data.mv_data = sval;
+		if (RES(MDB_NOTFOUND, mdb_del(txn, dbi, &key, &data))) {
+			j--;
+			mdb_txn_abort(txn);
+		} else {
+			E(mdb_txn_commit(txn));
+		}
+	}
+	free(values);
+	printf("Deleted %d values\n", j);
+
+	E(mdb_env_stat(env, &mst));
+	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+	printf("Cursor next\n");
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	printf("Cursor prev\n");
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_PREV)) == 0) {
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	mdb_cursor_close(cursor);
+	mdb_close(env, dbi);
+
+	mdb_txn_abort(txn);
+	mdb_env_close(env);
+
+	return 0;
+}
diff --git a/external/db_drivers/liblmdb64/mtest5.c b/external/db_drivers/liblmdb64/mtest5.c
new file mode 100644
index 000000000..39a8c728a
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mtest5.c
@@ -0,0 +1,135 @@
+/* mtest5.c - memory-mapped database tester/toy */
+/*
+ * Copyright 2011-2014 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+/* Tests for sorted duplicate DBs using cursor_put */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include "lmdb.h"
+
+#define E(expr) CHECK((rc = (expr)) == MDB_SUCCESS, #expr)
+#define RES(err, expr) ((rc = expr) == (err) || (CHECK(!rc, #expr), 0))
+#define CHECK(test, msg) ((test) ? (void)0 : ((void)fprintf(stderr, \
+	"%s:%d: %s: %s\n", __FILE__, __LINE__, msg, mdb_strerror(rc)), abort()))
+
+int main(int argc,char * argv[])
+{
+	int i = 0, j = 0, rc;
+	MDB_env *env;
+	MDB_dbi dbi;
+	MDB_val key, data;
+	MDB_txn *txn;
+	MDB_stat mst;
+	MDB_cursor *cursor;
+	int count;
+	int *values;
+	char sval[32];
+	char kval[sizeof(int)];
+
+	srand(time(NULL));
+
+	memset(sval, 0, sizeof(sval));
+
+	count = (rand()%384) + 64;
+	values = (int *)malloc(count*sizeof(int));
+
+	for(i = 0;i<count;i++) {
+		values[i] = rand()%1024;
+	}
+
+	E(mdb_env_create(&env));
+	E(mdb_env_set_mapsize(env, 10485760));
+	E(mdb_env_set_maxdbs(env, 4));
+	E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP|MDB_NOSYNC, 0664));
+	E(mdb_txn_begin(env, NULL, 0, &txn));
+	E(mdb_open(txn, "id2", MDB_CREATE|MDB_DUPSORT, &dbi));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+
+	key.mv_size = sizeof(int);
+	key.mv_data = kval;
+	data.mv_size = sizeof(sval);
+	data.mv_data = sval;
+
+	printf("Adding %d values\n", count);
+	for (i=0;i<count;i++) {
+		if (!(i & 0x0f))
+			sprintf(kval, "%03x", values[i]);
+		sprintf(sval, "%03x %d foo bar", values[i], values[i]);
+		if (RES(MDB_KEYEXIST, mdb_cursor_put(cursor, &key, &data, MDB_NODUPDATA)))
+			j++;
+	}
+	if (j) printf("%d duplicates skipped\n", j);
+	mdb_cursor_close(cursor);
+	E(mdb_txn_commit(txn));
+	E(mdb_env_stat(env, &mst));
+
+	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+		printf("key: %p %.*s, data: %p %.*s\n",
+			key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
+			data.mv_data, (int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	mdb_cursor_close(cursor);
+	mdb_txn_abort(txn);
+
+	j=0;
+
+	for (i= count - 1; i > -1; i-= (rand()%5)) {
+		j++;
+		txn=NULL;
+		E(mdb_txn_begin(env, NULL, 0, &txn));
+		sprintf(kval, "%03x", values[i & ~0x0f]);
+		sprintf(sval, "%03x %d foo bar", values[i], values[i]);
+		key.mv_size = sizeof(int);
+		key.mv_data = kval;
+		data.mv_size = sizeof(sval);
+		data.mv_data = sval;
+		if (RES(MDB_NOTFOUND, mdb_del(txn, dbi, &key, &data))) {
+			j--;
+			mdb_txn_abort(txn);
+		} else {
+			E(mdb_txn_commit(txn));
+		}
+	}
+	free(values);
+	printf("Deleted %d values\n", j);
+
+	E(mdb_env_stat(env, &mst));
+	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+	printf("Cursor next\n");
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	printf("Cursor prev\n");
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_PREV)) == 0) {
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	mdb_cursor_close(cursor);
+	mdb_close(env, dbi);
+
+	mdb_txn_abort(txn);
+	mdb_env_close(env);
+
+	return 0;
+}
diff --git a/external/db_drivers/liblmdb64/mtest6.c b/external/db_drivers/liblmdb64/mtest6.c
new file mode 100644
index 000000000..07d575893
--- /dev/null
+++ b/external/db_drivers/liblmdb64/mtest6.c
@@ -0,0 +1,137 @@
+/* mtest6.c - memory-mapped database tester/toy */
+/*
+ * Copyright 2011-2014 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+/* Tests for DB splits and merges */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include "lmdb.h"
+
+#define E(expr) CHECK((rc = (expr)) == MDB_SUCCESS, #expr)
+#define RES(err, expr) ((rc = expr) == (err) || (CHECK(!rc, #expr), 0))
+#define CHECK(test, msg) ((test) ? (void)0 : ((void)fprintf(stderr, \
+	"%s:%d: %s: %s\n", __FILE__, __LINE__, msg, mdb_strerror(rc)), abort()))
+
+char dkbuf[1024];
+
+int main(int argc,char * argv[])
+{
+	int i = 0, j = 0, rc;
+	MDB_env *env;
+	MDB_dbi dbi;
+	MDB_val key, data;
+	MDB_txn *txn;
+	MDB_stat mst;
+	MDB_cursor *cursor;
+	int count;
+	int *values;
+	long kval;
+	char *sval;
+
+	srand(time(NULL));
+
+	E(mdb_env_create(&env));
+	E(mdb_env_set_mapsize(env, 10485760));
+	E(mdb_env_set_maxdbs(env, 4));
+	E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP|MDB_NOSYNC, 0664));
+	E(mdb_txn_begin(env, NULL, 0, &txn));
+	E(mdb_open(txn, "id6", MDB_CREATE|MDB_INTEGERKEY, &dbi));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+	E(mdb_stat(txn, dbi, &mst));
+
+	sval = calloc(1, mst.ms_psize / 4);
+	key.mv_size = sizeof(long);
+	key.mv_data = &kval;
+	data.mv_size = mst.ms_psize / 4 - 30;
+	data.mv_data = sval;
+
+	printf("Adding 12 values, should yield 3 splits\n");
+	for (i=0;i<12;i++) {
+		kval = i*5;
+		sprintf(sval, "%08x", kval);
+		(void)RES(MDB_KEYEXIST, mdb_cursor_put(cursor, &key, &data, MDB_NOOVERWRITE));
+	}
+	printf("Adding 12 more values, should yield 3 splits\n");
+	for (i=0;i<12;i++) {
+		kval = i*5+4;
+		sprintf(sval, "%08x", kval);
+		(void)RES(MDB_KEYEXIST, mdb_cursor_put(cursor, &key, &data, MDB_NOOVERWRITE));
+	}
+	printf("Adding 12 more values, should yield 3 splits\n");
+	for (i=0;i<12;i++) {
+		kval = i*5+1;
+		sprintf(sval, "%08x", kval);
+		(void)RES(MDB_KEYEXIST, mdb_cursor_put(cursor, &key, &data, MDB_NOOVERWRITE));
+	}
+	E(mdb_cursor_get(cursor, &key, &data, MDB_FIRST));
+
+	do {
+		printf("key: %p %s, data: %p %.*s\n",
+			key.mv_data,  mdb_dkey(&key, dkbuf),
+			data.mv_data, (int) data.mv_size, (char *) data.mv_data);
+	} while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0);
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	mdb_cursor_close(cursor);
+	mdb_txn_commit(txn);
+
+#if 0
+	j=0;
+
+	for (i= count - 1; i > -1; i-= (rand()%5)) {
+		j++;
+		txn=NULL;
+		E(mdb_txn_begin(env, NULL, 0, &txn));
+		sprintf(kval, "%03x", values[i & ~0x0f]);
+		sprintf(sval, "%03x %d foo bar", values[i], values[i]);
+		key.mv_size = sizeof(int);
+		key.mv_data = kval;
+		data.mv_size = sizeof(sval);
+		data.mv_data = sval;
+		if (RES(MDB_NOTFOUND, mdb_del(txn, dbi, &key, &data))) {
+			j--;
+			mdb_txn_abort(txn);
+		} else {
+			E(mdb_txn_commit(txn));
+		}
+	}
+	free(values);
+	printf("Deleted %d values\n", j);
+
+	E(mdb_env_stat(env, &mst));
+	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_cursor_open(txn, dbi, &cursor));
+	printf("Cursor next\n");
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	printf("Cursor prev\n");
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_PREV)) == 0) {
+		printf("key: %.*s, data: %.*s\n",
+			(int) key.mv_size,  (char *) key.mv_data,
+			(int) data.mv_size, (char *) data.mv_data);
+	}
+	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
+	mdb_cursor_close(cursor);
+	mdb_close(env, dbi);
+
+	mdb_txn_abort(txn);
+#endif
+	mdb_env_close(env);
+
+	return 0;
+}
diff --git a/external/db_drivers/liblmdb64/sample-bdb.txt b/external/db_drivers/liblmdb64/sample-bdb.txt
new file mode 100644
index 000000000..6a959bd68
--- /dev/null
+++ b/external/db_drivers/liblmdb64/sample-bdb.txt
@@ -0,0 +1,73 @@
+/* sample-bdb.txt - BerkeleyDB toy/sample
+ *
+ * Do a line-by-line comparison of this and sample-mdb.txt
+ */
+/*
+ * Copyright 2012 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+#include <stdio.h>
+#include <string.h>
+#include <db.h>
+
+int main(int argc,char * argv[])
+{
+	int rc;
+	DB_ENV *env;
+	DB *dbi;
+	DBT key, data;
+	DB_TXN *txn;
+	DBC *cursor;
+	char sval[32], kval[32];
+
+	/* Note: Most error checking omitted for simplicity */
+
+#define FLAGS (DB_INIT_LOCK|DB_INIT_LOG|DB_INIT_TXN|DB_INIT_MPOOL|DB_CREATE|DB_THREAD)
+	rc = db_env_create(&env, 0);
+	rc = env->open(env, "./testdb", FLAGS, 0664);
+	rc = db_create(&dbi, env, 0);
+	rc = env->txn_begin(env, NULL, &txn, 0);
+	rc = dbi->open(dbi, txn, "test.bdb", NULL, DB_BTREE, DB_CREATE, 0664);
+
+	memset(&key, 0, sizeof(DBT));
+	memset(&data, 0, sizeof(DBT));
+	key.size = sizeof(int);
+	key.data = sval;
+	data.size = sizeof(sval);
+	data.data = sval;
+
+	sprintf(sval, "%03x %d foo bar", 32, 3141592);
+	rc = dbi->put(dbi, txn, &key, &data, 0);
+	rc = txn->commit(txn, 0);
+	if (rc) {
+		fprintf(stderr, "txn->commit: (%d) %s\n", rc, db_strerror(rc));
+		goto leave;
+	}
+	rc = env->txn_begin(env, NULL, &txn, 0);
+	rc = dbi->cursor(dbi, txn, &cursor, 0);
+	key.flags = DB_DBT_USERMEM;
+	key.data = kval;
+	key.ulen = sizeof(kval);
+	data.flags = DB_DBT_USERMEM;
+	data.data = sval;
+	data.ulen = sizeof(sval);
+	while ((rc = cursor->c_get(cursor, &key, &data, DB_NEXT)) == 0) {
+		printf("key: %p %.*s, data: %p %.*s\n",
+			key.data,  (int) key.size,  (char *) key.data,
+			data.data, (int) data.size, (char *) data.data);
+	}
+	rc = cursor->c_close(cursor);
+	rc = txn->abort(txn);
+leave:
+	rc = dbi->close(dbi, 0);
+	rc = env->close(env, 0);
+	return rc;
+}
diff --git a/external/db_drivers/liblmdb64/sample-mdb.txt b/external/db_drivers/liblmdb64/sample-mdb.txt
new file mode 100644
index 000000000..a233ec5dd
--- /dev/null
+++ b/external/db_drivers/liblmdb64/sample-mdb.txt
@@ -0,0 +1,62 @@
+/* sample-mdb.txt - MDB toy/sample
+ *
+ * Do a line-by-line comparison of this and sample-bdb.txt
+ */
+/*
+ * Copyright 2012 Howard Chu, Symas Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+#include <stdio.h>
+#include "lmdb.h"
+
+int main(int argc,char * argv[])
+{
+	int rc;
+	MDB_env *env;
+	MDB_dbi dbi;
+	MDB_val key, data;
+	MDB_txn *txn;
+	MDB_cursor *cursor;
+	char sval[32];
+
+	/* Note: Most error checking omitted for simplicity */
+
+	rc = mdb_env_create(&env);
+	rc = mdb_env_open(env, "./testdb", 0, 0664);
+	rc = mdb_txn_begin(env, NULL, 0, &txn);
+	rc = mdb_open(txn, NULL, 0, &dbi);
+
+	key.mv_size = sizeof(int);
+	key.mv_data = sval;
+	data.mv_size = sizeof(sval);
+	data.mv_data = sval;
+
+	sprintf(sval, "%03x %d foo bar", 32, 3141592);
+	rc = mdb_put(txn, dbi, &key, &data, 0);
+	rc = mdb_txn_commit(txn);
+	if (rc) {
+		fprintf(stderr, "mdb_txn_commit: (%d) %s\n", rc, mdb_strerror(rc));
+		goto leave;
+	}
+	rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
+	rc = mdb_cursor_open(txn, dbi, &cursor);
+	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+		printf("key: %p %.*s, data: %p %.*s\n",
+			key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
+			data.mv_data, (int) data.mv_size, (char *) data.mv_data);
+	}
+	mdb_cursor_close(cursor);
+	mdb_txn_abort(txn);
+leave:
+	mdb_close(env, dbi);
+	mdb_env_close(env);
+	return 0;
+}
diff --git a/external/db_drivers/liblmdb64/tooltag b/external/db_drivers/liblmdb64/tooltag
new file mode 100644
index 000000000..229bf16ba
--- /dev/null
+++ b/external/db_drivers/liblmdb64/tooltag
@@ -0,0 +1,22 @@
+<tagfile>
+  <compound kind="page">
+    <name>mdb_copy_1</name>
+	<title>mdb_copy - environment copy tool</title>
+	<filename>mdb_copy.1</filename>
+  </compound>
+  <compound kind="page">
+    <name>mdb_dump_1</name>
+	<title>mdb_dump - environment export tool</title>
+	<filename>mdb_dump.1</filename>
+  </compound>
+  <compound kind="page">
+    <name>mdb_load_1</name>
+	<title>mdb_load - environment import tool</title>
+	<filename>mdb_load.1</filename>
+  </compound>
+  <compound kind="page">
+    <name>mdb_stat_1</name>
+	<title>mdb_stat - environment status tool</title>
+	<filename>mdb_stat.1</filename>
+  </compound>
+</tagfile>
diff --git a/external/unbound/CMakeLists.txt b/external/unbound/CMakeLists.txt
index fdfa0a0fe..b00ff9b3c 100644
--- a/external/unbound/CMakeLists.txt
+++ b/external/unbound/CMakeLists.txt
@@ -1,3 +1,31 @@
+# Copyright (c) 2014-2015, The Monero Project
+# 
+# All rights reserved.
+# 
+# Redistribution and use in source and binary forms, with or without modification, are
+# permitted provided that the following conditions are met:
+# 
+# 1. Redistributions of source code must retain the above copyright notice, this list of
+#    conditions and the following disclaimer.
+# 
+# 2. Redistributions in binary form must reproduce the above copyright notice, this list
+#    of conditions and the following disclaimer in the documentation and/or other
+#    materials provided with the distribution.
+# 
+# 3. Neither the name of the copyright holder nor the names of its contributors may be
+#    used to endorse or promote products derived from this software without specific
+#    prior written permission.
+# 
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+# THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+# THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 cmake_minimum_required(VERSION 2.8.7)
 
 project(unbound C)
diff --git a/src/blockchain_converter/CMakeLists.txt b/src/blockchain_converter/CMakeLists.txt
index a91624f4f..e0f3be901 100644
--- a/src/blockchain_converter/CMakeLists.txt
+++ b/src/blockchain_converter/CMakeLists.txt
@@ -35,6 +35,32 @@ set(blockchain_converter_private_headers)
 bitmonero_private_headers(blockchain_converter
 	  ${blockchain_converter_private_headers})
 
+set(blockchain_import_sources
+  blockchain_import.cpp
+  )
+
+set(blockchain_import_private_headers
+  import.h
+  fake_core.h
+  )
+
+bitmonero_private_headers(blockchain_import
+	  ${blockchain_import_private_headers})
+
+set(blockchain_export_sources
+  blockchain_export.cpp
+  )
+
+set(blockchain_export_private_headers
+  import.h
+  blockchain_export.h
+  )
+
+bitmonero_private_headers(blockchain_export
+	  ${blockchain_export_private_headers})
+
+
+
 if (BLOCKCHAIN_DB STREQUAL DB_LMDB)
 bitmonero_add_executable(blockchain_converter
   ${blockchain_converter_sources}
@@ -52,3 +78,33 @@ set_property(TARGET blockchain_converter
 	PROPERTY
 	OUTPUT_NAME "blockchain_converter")
 endif ()
+
+bitmonero_add_executable(blockchain_import
+  ${blockchain_import_sources}
+  ${blockchain_import_private_headers})
+
+target_link_libraries(blockchain_import
+  LINK_PRIVATE
+    cryptonote_core
+    ${CMAKE_THREAD_LIBS_INIT})
+
+add_dependencies(blockchain_import
+	version)
+set_property(TARGET blockchain_import
+	PROPERTY
+	OUTPUT_NAME "blockchain_import")
+
+bitmonero_add_executable(blockchain_export
+  ${blockchain_export_sources}
+  ${blockchain_export_private_headers})
+
+target_link_libraries(blockchain_export
+  LINK_PRIVATE
+    cryptonote_core
+    ${CMAKE_THREAD_LIBS_INIT})
+
+add_dependencies(blockchain_export
+	version)
+set_property(TARGET blockchain_export
+	PROPERTY
+	OUTPUT_NAME "blockchain_export")
diff --git a/src/blockchain_converter/blockchain_converter.cpp b/src/blockchain_converter/blockchain_converter.cpp
index 8ac9b81bb..eaf799a36 100644
--- a/src/blockchain_converter/blockchain_converter.cpp
+++ b/src/blockchain_converter/blockchain_converter.cpp
@@ -38,52 +38,179 @@
 #include "cryptonote_core/blockchain.h"
 #include "blockchain_db/lmdb/db_lmdb.h"
 #include "cryptonote_core/tx_pool.h"
+#include "common/command_line.h"
+#include "serialization/json_utils.h"
+#include "include_base_utils.h"
+#include "version.h"
 #include <iostream>
 
+// CONFIG
+static bool opt_batch   = true;
+static bool opt_testnet = false;
+
+// number of blocks per batch transaction
+// adjustable through command-line argument according to available RAM
+static uint64_t db_batch_size = 20000;
+
+
+namespace po = boost::program_options;
+
 using namespace cryptonote;
+using namespace epee;
 
 struct fake_core
 {
-  tx_memory_pool m_pool;
   Blockchain dummy;
+  tx_memory_pool m_pool;
 
   blockchain_storage m_storage;
 
-
-  fake_core(const boost::filesystem::path &path) : m_pool(dummy), dummy(m_pool), m_storage(&m_pool)
+#if !defined(BLOCKCHAIN_DB)
+  // for multi_db_runtime:
+  fake_core(const boost::filesystem::path &path, const bool use_testnet) : dummy(m_pool), m_pool(&dummy), m_storage(m_pool)
+#else
+  // for multi_db_compile:
+  fake_core(const boost::filesystem::path &path, const bool use_testnet) : dummy(m_pool), m_pool(dummy), m_storage(&m_pool)
+#endif
   {
     m_pool.init(path.string());
-    m_storage.init(path.string(), false);
+    m_storage.init(path.string(), use_testnet);
   }
 };
 
 int main(int argc, char* argv[])
 {
-  std::string dir = tools::get_default_data_dir();
-  boost::filesystem::path default_data_path {dir};
-  if (argc >= 2 && !strcmp(argv[1], "--testnet")) {
-    default_data_path /= "testnet";
+  uint64_t height = 0;
+  uint64_t start_block = 0;
+  uint64_t end_block = 0;
+  uint64_t num_blocks = 0;
+
+  boost::filesystem::path default_data_path {tools::get_default_data_dir()};
+  boost::filesystem::path default_testnet_data_path {default_data_path / "testnet"};
+
+
+  po::options_description desc_cmd_only("Command line options");
+  po::options_description desc_cmd_sett("Command line options and settings options");
+  const command_line::arg_descriptor<uint32_t> arg_log_level   =  {"log-level", "", LOG_LEVEL_0};
+  const command_line::arg_descriptor<uint64_t> arg_batch_size  =  {"batch-size", "", db_batch_size};
+  const command_line::arg_descriptor<bool>     arg_testnet_on  = {
+    "testnet"
+      , "Run on testnet."
+      , opt_testnet
+  };
+  const command_line::arg_descriptor<uint64_t> arg_block_number =
+  {"block-number", "Number of blocks (default: use entire source blockchain)",
+    0};
+
+  command_line::add_arg(desc_cmd_sett, command_line::arg_data_dir, default_data_path.string());
+  command_line::add_arg(desc_cmd_sett, command_line::arg_testnet_data_dir, default_testnet_data_path.string());
+  command_line::add_arg(desc_cmd_sett, arg_log_level);
+  command_line::add_arg(desc_cmd_sett, arg_batch_size);
+  command_line::add_arg(desc_cmd_sett, arg_testnet_on);
+  command_line::add_arg(desc_cmd_sett, arg_block_number);
+
+  command_line::add_arg(desc_cmd_only, command_line::arg_help);
+
+  const command_line::arg_descriptor<bool> arg_batch  =  {"batch",
+    "Batch transactions for faster import", true};
+
+  // call add_options() directly for these arguments since command_line helpers
+  // support only boolean switch, not boolean argument
+  desc_cmd_sett.add_options()
+    (arg_batch.name, make_semantic(arg_batch), arg_batch.description)
+    ;
+
+  po::options_description desc_options("Allowed options");
+  desc_options.add(desc_cmd_only).add(desc_cmd_sett);
+
+
+  po::variables_map vm;
+  bool r = command_line::handle_error_helper(desc_options, [&]()
+  {
+    po::store(po::parse_command_line(argc, argv, desc_options), vm);
+    po::notify(vm);
+
+    return true;
+  });
+  if (!r)
+    return 1;
+
+  int log_level = command_line::get_arg(vm, arg_log_level);
+  opt_batch     = command_line::get_arg(vm, arg_batch);
+  db_batch_size = command_line::get_arg(vm, arg_batch_size);
+
+  if (command_line::get_arg(vm, command_line::arg_help))
+  {
+    std::cout << CRYPTONOTE_NAME << " v" << MONERO_VERSION_FULL << ENDL << ENDL;
+    std::cout << desc_options << std::endl;
+    return 1;
   }
 
-  fake_core c(default_data_path);
+  if (! opt_batch && ! vm["batch-size"].defaulted())
+  {
+    std::cerr << "Error: batch-size set, but batch option not enabled" << ENDL;
+    return 1;
+  }
+  if (! db_batch_size)
+  {
+    std::cerr << "Error: batch-size must be > 0" << ENDL;
+    return 1;
+  }
 
-  BlockchainDB *blockchain;
+  log_space::get_set_log_detalisation_level(true, log_level);
+  log_space::log_singletone::add_logger(LOGGER_CONSOLE, NULL, NULL);
+  LOG_PRINT_L0("Starting...");
 
-  blockchain = new BlockchainLMDB();
+  std::string src_folder;
+  opt_testnet = command_line::get_arg(vm, arg_testnet_on);
+  auto data_dir_arg = opt_testnet ? command_line::arg_testnet_data_dir : command_line::arg_data_dir;
+  src_folder = command_line::get_arg(vm, data_dir_arg);
+  boost::filesystem::path dest_folder(src_folder);
 
-  boost::filesystem::path db_path(default_data_path);
+  num_blocks = command_line::get_arg(vm, arg_block_number);
 
-  db_path /= blockchain->get_db_name();
+  if (opt_batch)
+  {
+    LOG_PRINT_L0("batch:   " << std::boolalpha << opt_batch << std::noboolalpha
+        << "  batch size: " << db_batch_size);
+  }
+  else
+  {
+    LOG_PRINT_L0("batch:   " << std::boolalpha << opt_batch << std::noboolalpha);
+  }
+  LOG_PRINT_L0("testnet: " << std::boolalpha << opt_testnet << std::noboolalpha);
+
+  fake_core c(src_folder, opt_testnet);
 
-  blockchain->open(db_path.string());
+  height = c.m_storage.get_current_blockchain_height();
+  if (! num_blocks || num_blocks > height)
+    end_block = height - 1;
+  else
+    end_block = start_block + num_blocks - 1;
+
+  BlockchainDB *blockchain;
+  blockchain = new BlockchainLMDB(opt_batch);
+  dest_folder /= blockchain->get_db_name();
+  LOG_PRINT_L0("Source blockchain: " << src_folder);
+  LOG_PRINT_L0("Dest blockchain:   " << dest_folder.string());
+  LOG_PRINT_L0("Opening LMDB: " << dest_folder.string());
+  blockchain->open(dest_folder.string());
 
-  for (uint64_t height, i = 0; i < (height = c.m_storage.get_current_blockchain_height()); ++i)
+  if (opt_batch)
+    blockchain->batch_start();
+  uint64_t i = 0;
+  for (i = start_block; i < end_block + 1; ++i)
   {
-    if (i % 10 == 0)
+    // block: i  height: i+1  end height: end_block + 1
+    if ((i+1) % 10 == 0)
     {
-      std::cout << "\r                   \r" << "block " << i << "/" << height
-         << " (" << (i+1)*100/height<< "%)" << std::flush;
+      std::cout << "\r                   \r" << "height " << i+1 << "/" <<
+        end_block+1 << " (" << (i+1)*100/(end_block+1)<< "%)" << std::flush;
     }
+    // for debugging:
+    // std::cout << "height " << i+1 << "/" << end_block+1
+    //   << " ((" << i+1 << ")*100/(end_block+1))" << "%)" << ENDL;
+
     block b = c.m_storage.get_block(i);
     size_t bsize = c.m_storage.get_block_size(i);
     difficulty_type bdiff = c.m_storage.get_block_cumulative_difficulty(i);
@@ -94,8 +221,8 @@ int main(int argc, char* argv[])
     c.m_storage.get_transactions(b.tx_hashes, txs, missed);
     if (missed.size())
     {
-      std::cout << std::endl;
-      std::cerr << "Missed transaction(s) for block at height " << i << ", exiting" << std::endl;
+      std::cout << ENDL;
+      std::cerr << "Missed transaction(s) for block at height " << i + 1 << ", exiting" << ENDL;
       delete blockchain;
       return 1;
     }
@@ -103,17 +230,40 @@ int main(int argc, char* argv[])
     try
     {
       blockchain->add_block(b, bsize, bdiff, bcoins, txs);
+
+      if (opt_batch)
+      {
+        if ((i < end_block) && ((i + 1) % db_batch_size == 0))
+        {
+          std::cout << "\r                   \r";
+          std::cout << "[- batch commit at height " << i + 1 << " -]" << ENDL;
+          blockchain->batch_stop();
+          blockchain->batch_start();
+          std::cout << ENDL;
+          blockchain->show_stats();
+        }
+      }
     }
     catch (const std::exception& e)
     {
-      std::cout << std::endl;
-      std::cerr << "Error adding block to new blockchain: " << e.what() << std::endl;
+      std::cout << ENDL;
+      std::cerr << "Error adding block to new blockchain: " << e.what() << ENDL;
       delete blockchain;
       return 2;
     }
   }
+  if (opt_batch)
+  {
+    std::cout << "\r                   \r" << "height " << i << "/" <<
+      end_block+1 << " (" << (i)*100/(end_block+1)<< "%)" << std::flush;
+    std::cout << ENDL;
+    std::cout << "[- batch commit at height " << i << " -]" << ENDL;
+    blockchain->batch_stop();
+  }
+  std::cout << ENDL;
+  blockchain->show_stats();
+  std::cout << "Finished at height: " << i << "  block: " << i-1 << ENDL;
 
-  std::cout << std::endl;
   delete blockchain;
   return 0;
 }
diff --git a/src/blockchain_converter/blockchain_export.cpp b/src/blockchain_converter/blockchain_export.cpp
new file mode 100644
index 000000000..2467951de
--- /dev/null
+++ b/src/blockchain_converter/blockchain_export.cpp
@@ -0,0 +1,386 @@
+// Copyright (c) 2014-2015, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <algorithm>
+#include <cstdio>
+#include <fstream>
+#include <boost/iostreams/copy.hpp>
+#include <atomic>
+
+#include <boost/archive/binary_oarchive.hpp>
+#include <boost/archive/binary_iarchive.hpp>
+#include <boost/iostreams/stream_buffer.hpp>
+#include <boost/iostreams/stream.hpp>
+#include <boost/iostreams/device/back_inserter.hpp>
+#include <boost/iostreams/filtering_streambuf.hpp>
+#include <boost/iostreams/filter/bzip2.hpp>
+#include "common/command_line.h"
+#include "version.h"
+#include "blockchain_export.h"
+#include "cryptonote_core/cryptonote_boost_serialization.h"
+
+#include "import.h"
+
+static int max_chunk = 0;
+static size_t height;
+
+namespace po = boost::program_options;
+
+using namespace cryptonote;
+using namespace epee;
+
+bool BlockchainExport::open(const boost::filesystem::path& dir_path)
+{
+  if (boost::filesystem::exists(dir_path))
+  {
+    if (!boost::filesystem::is_directory(dir_path))
+    {
+      LOG_PRINT_RED_L0("export directory path is a file: " << dir_path);
+      return false;
+    }
+  }
+  else
+  {
+    if (!boost::filesystem::create_directory(dir_path))
+    {
+      LOG_PRINT_RED_L0("Failed to create directory " << dir_path);
+      return false;
+    }
+  }
+
+  std::string file_path = (dir_path / BLOCKCHAIN_RAW).string();
+  m_raw_data_file = new std::ofstream();
+  m_raw_data_file->open(file_path , std::ios_base::binary | std::ios_base::out| std::ios::trunc);
+  if (m_raw_data_file->fail())
+    return false;
+
+  m_output_stream = new boost::iostreams::stream<boost::iostreams::back_insert_device<buffer_type>>(m_buffer);
+  m_raw_archive = new boost::archive::binary_oarchive(*m_output_stream);
+  if (m_raw_archive == NULL)
+    return false;
+
+  return true;
+}
+
+void BlockchainExport::flush_chunk()
+{
+  m_output_stream->flush();
+  char buffer[STR_LENGTH_OF_INT + 1];
+  int chunk_size = (int) m_buffer.size();
+  if (chunk_size > BUFFER_SIZE)
+  {
+    LOG_PRINT_L0("WARNING: chunk_size " << chunk_size << " > BUFFER_SIZE " << BUFFER_SIZE);
+  }
+  sprintf(buffer, STR_FORMAT_OF_INT, chunk_size);
+  m_raw_data_file->write(buffer, STR_LENGTH_OF_INT);
+  if (max_chunk < chunk_size)
+  {
+    max_chunk = chunk_size;
+  }
+  long pos_before = m_raw_data_file->tellp();
+  std::copy(m_buffer.begin(), m_buffer.end(), std::ostreambuf_iterator<char>(*m_raw_data_file));
+  m_raw_data_file->flush();
+  long pos_after = m_raw_data_file->tellp();
+  long num_chars_written = pos_after - pos_before;
+  if ((int) num_chars_written != chunk_size)
+  {
+    LOG_PRINT_RED_L0("INTERNAL ERROR: num chars wrote NEQ buffer size. height = " << height);
+  }
+
+  m_buffer.clear();
+  delete m_raw_archive;
+  delete m_output_stream;
+  m_output_stream = new boost::iostreams::stream<boost::iostreams::back_insert_device<buffer_type>>(m_buffer);
+  m_raw_archive = new boost::archive::binary_oarchive(*m_output_stream);
+}
+
+void BlockchainExport::serialize_block_to_text_buffer(const block& block)
+{
+  *m_raw_archive << block;
+}
+
+void BlockchainExport::buffer_serialize_tx(const transaction& tx)
+{
+  *m_raw_archive << tx;
+}
+
+void BlockchainExport::buffer_write_num_txs(const std::list<transaction> txs)
+{
+  int n = txs.size();
+  *m_raw_archive << n;
+}
+
+void BlockchainExport::write_block(block& block)
+{
+  serialize_block_to_text_buffer(block);
+  std::list<transaction> txs;
+
+  uint64_t block_height = boost::get<txin_gen>(block.miner_tx.vin.front()).height;
+
+  // put coinbase transaction first
+  transaction coinbase_tx = block.miner_tx;
+  crypto::hash coinbase_tx_hash = get_transaction_hash(coinbase_tx);
+#if SOURCE_DB == DB_MEMORY
+  const transaction* cb_tx_full = m_blockchain_storage->get_tx(coinbase_tx_hash);
+#else
+  transaction cb_tx_full = m_blockchain_storage->get_db()->get_tx(coinbase_tx_hash);
+#endif
+
+#if SOURCE_DB == DB_MEMORY
+  if (cb_tx_full != NULL)
+  {
+    txs.push_back(*cb_tx_full);
+  }
+#else
+  // TODO: should check and abort if cb_tx_full equals null_hash?
+  txs.push_back(cb_tx_full);
+#endif
+
+  // now add all regular transactions
+  BOOST_FOREACH(const auto& tx_id, block.tx_hashes)
+  {
+#if SOURCE_DB == DB_MEMORY
+    const transaction* tx = m_blockchain_storage->get_tx(tx_id);
+#else
+    transaction tx = m_blockchain_storage->get_db()->get_tx(tx_id);
+#endif
+
+#if SOURCE_DB == DB_MEMORY
+    if(tx == NULL)
+    {
+      if (! m_tx_pool)
+        throw std::runtime_error("Aborting: tx == NULL, so memory pool required to get tx, but memory pool isn't enabled");
+      else
+      {
+        transaction tx;
+        if(m_tx_pool->get_transaction(tx_id, tx))
+          txs.push_back(tx);
+        else
+          throw std::runtime_error("Aborting: tx not found in pool");
+      }
+    }
+    else
+      txs.push_back(*tx);
+#else
+    txs.push_back(tx);
+#endif
+  }
+
+  // serialize all txs to the persistant storage
+  buffer_write_num_txs(txs);
+  BOOST_FOREACH(const auto& tx, txs)
+  {
+    buffer_serialize_tx(tx);
+  }
+
+  // These three attributes are currently necessary for a fast import that adds blocks without verification.
+  bool include_extra_block_data = true;
+  if (include_extra_block_data)
+  {
+#if SOURCE_DB == DB_MEMORY
+    size_t block_size = m_blockchain_storage->get_block_size(block_height);
+#else
+    size_t block_size = m_blockchain_storage->get_db()->get_block_size(block_height);
+#endif
+#if SOURCE_DB == DB_MEMORY
+    difficulty_type cumulative_difficulty = m_blockchain_storage->get_block_cumulative_difficulty(block_height);
+#else
+    difficulty_type cumulative_difficulty = m_blockchain_storage->get_db()->get_block_cumulative_difficulty(block_height);
+#endif
+#if SOURCE_DB == DB_MEMORY
+    uint64_t coins_generated = m_blockchain_storage->get_block_coins_generated(block_height);
+#else
+    // TODO TEST to verify that this is the equivalent. make sure no off-by-one error with block height vs block number
+    uint64_t coins_generated = m_blockchain_storage->get_db()->get_block_already_generated_coins(block_height);
+#endif
+
+    *m_raw_archive << block_size;
+    *m_raw_archive << cumulative_difficulty;
+    *m_raw_archive << coins_generated;
+  }
+}
+
+bool BlockchainExport::BlockchainExport::close()
+{
+  if (m_raw_data_file->fail())
+    return false;
+
+  m_raw_data_file->flush();
+  delete m_raw_archive;
+  delete m_output_stream;
+  delete m_raw_data_file;
+  return true;
+}
+
+
+#if SOURCE_DB == DB_MEMORY
+bool BlockchainExport::store_blockchain_raw(blockchain_storage* _blockchain_storage, tx_memory_pool* _tx_pool, boost::filesystem::path& output_dir, uint64_t use_block_height)
+#else
+bool BlockchainExport::store_blockchain_raw(Blockchain* _blockchain_storage, tx_memory_pool* _tx_pool, boost::filesystem::path& output_dir, uint64_t use_block_height)
+#endif
+{
+  uint64_t use_block_height2 = 0;
+  m_blockchain_storage = _blockchain_storage;
+  m_tx_pool = _tx_pool;
+  LOG_PRINT_L0("Storing blocks raw data...");
+  if (!BlockchainExport::open(output_dir))
+  {
+    LOG_PRINT_RED_L0("failed to open raw file for write");
+    return false;
+  }
+  block b;
+  LOG_PRINT_L0("source blockchain height: " <<  m_blockchain_storage->get_current_blockchain_height());
+  LOG_PRINT_L0("requested block height: " << use_block_height);
+  if ((use_block_height > 0) && (use_block_height < m_blockchain_storage->get_current_blockchain_height()))
+    use_block_height2 = use_block_height;
+  else
+  {
+    use_block_height2 = m_blockchain_storage->get_current_blockchain_height();
+    LOG_PRINT_L0("using block height: " << use_block_height2);
+  }
+  for (height=0; height < use_block_height2; ++height)
+  {
+    crypto::hash hash = m_blockchain_storage->get_block_id_by_height(height);
+    m_blockchain_storage->get_block_by_hash(hash, b);
+    write_block(b);
+    if (height % NUM_BLOCKS_PER_CHUNK == 0) {
+      flush_chunk();
+    }
+  }
+  if (height % NUM_BLOCKS_PER_CHUNK != 0)
+  {
+    flush_chunk();
+  }
+
+  LOG_PRINT_L0("longest chunk was " << max_chunk << " bytes");
+  return BlockchainExport::close();
+}
+
+
+int main(int argc, char* argv[])
+{
+  uint32_t log_level = 0;
+  uint64_t block_height = 0;
+  std::string import_filename = BLOCKCHAIN_RAW;
+
+  boost::filesystem::path default_data_path {tools::get_default_data_dir()};
+  boost::filesystem::path default_testnet_data_path {default_data_path / "testnet"};
+
+  po::options_description desc_cmd_only("Command line options");
+  po::options_description desc_cmd_sett("Command line options and settings options");
+  const command_line::arg_descriptor<uint32_t> arg_log_level   =  {"log-level",  "", log_level};
+  const command_line::arg_descriptor<uint64_t> arg_block_height =  {"block-number", "", block_height};
+  const command_line::arg_descriptor<bool>     arg_testnet_on  = {
+    "testnet"
+      , "Run on testnet."
+      , false
+  };
+
+
+  command_line::add_arg(desc_cmd_sett, command_line::arg_data_dir, default_data_path.string());
+  command_line::add_arg(desc_cmd_sett, command_line::arg_testnet_data_dir, default_testnet_data_path.string());
+  command_line::add_arg(desc_cmd_sett, arg_log_level);
+  command_line::add_arg(desc_cmd_sett, arg_block_height);
+  command_line::add_arg(desc_cmd_sett, arg_testnet_on);
+
+  command_line::add_arg(desc_cmd_only, command_line::arg_help);
+
+  po::options_description desc_options("Allowed options");
+  desc_options.add(desc_cmd_only).add(desc_cmd_sett);
+
+  po::variables_map vm;
+  bool r = command_line::handle_error_helper(desc_options, [&]()
+  {
+    po::store(po::parse_command_line(argc, argv, desc_options), vm);
+    po::notify(vm);
+    return true;
+  });
+  if (! r)
+    return 1;
+
+  if (command_line::get_arg(vm, command_line::arg_help))
+  {
+    std::cout << CRYPTONOTE_NAME << " v" << MONERO_VERSION_FULL << ENDL << ENDL;
+    std::cout << desc_options << std::endl;
+    return 1;
+  }
+
+  log_level    = command_line::get_arg(vm, arg_log_level);
+  block_height = command_line::get_arg(vm, arg_block_height);
+
+  log_space::get_set_log_detalisation_level(true, log_level);
+  log_space::log_singletone::add_logger(LOGGER_CONSOLE, NULL, NULL);
+  LOG_PRINT_L0("Starting...");
+  LOG_PRINT_L0("Setting log level = " << log_level);
+
+  bool opt_testnet = command_line::get_arg(vm, arg_testnet_on);
+
+  std::string m_config_folder;
+
+  auto data_dir_arg = opt_testnet ? command_line::arg_testnet_data_dir : command_line::arg_data_dir;
+  m_config_folder = command_line::get_arg(vm, data_dir_arg);
+  boost::filesystem::path output_dir {m_config_folder};
+  output_dir /= "export";
+  LOG_PRINT_L0("Export directory: " << output_dir.string());
+
+  // If we wanted to use the memory pool, we would set up a fake_core.
+
+#if SOURCE_DB == DB_MEMORY
+  // blockchain_storage* core_storage = NULL;
+  // tx_memory_pool m_mempool(*core_storage); // is this fake anyway? just passing in NULL! so m_mempool can't be used anyway, right?
+  // core_storage = new blockchain_storage(&m_mempool);
+
+  blockchain_storage* core_storage = new blockchain_storage(NULL);
+  LOG_PRINT_L0("Initializing source blockchain (in-memory database)");
+  r = core_storage->init(m_config_folder, opt_testnet);
+#else
+  // Use Blockchain instead of lower-level BlockchainDB for two reasons:
+  // 1. Blockchain has the init() method for easy setup
+  // 2. exporter needs to use get_current_blockchain_height(), get_block_id_by_height(), get_block_by_hash()
+  //
+  // cannot match blockchain_storage setup above with just one line,
+  // e.g.
+  //   Blockchain* core_storage = new Blockchain(NULL);
+  // because unlike blockchain_storage constructor, which takes a pointer to
+  // tx_memory_pool, Blockchain's constructor takes tx_memory_pool object.
+  LOG_PRINT_L0("Initializing source blockchain (BlockchainDB)");
+  Blockchain* core_storage = NULL;
+  tx_memory_pool m_mempool(*core_storage);
+  core_storage = new Blockchain(m_mempool);
+  r = core_storage->init(m_config_folder, opt_testnet);
+#endif
+
+  CHECK_AND_ASSERT_MES(r, false, "Failed to initialize source blockchain storage");
+  LOG_PRINT_L0("Source blockchain storage initialized OK");
+  LOG_PRINT_L0("Exporting blockchain raw data...");
+
+  BlockchainExport be;
+  r = be.store_blockchain_raw(core_storage, NULL, output_dir, block_height);
+  CHECK_AND_ASSERT_MES(r, false, "Failed to export blockchain raw data");
+  LOG_PRINT_L0("Blockchain raw data exported OK");
+}
diff --git a/src/blockchain_converter/blockchain_export.h b/src/blockchain_converter/blockchain_export.h
new file mode 100644
index 000000000..43e25c039
--- /dev/null
+++ b/src/blockchain_converter/blockchain_export.h
@@ -0,0 +1,87 @@
+// Copyright (c) 2014-2015, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+#include <boost/archive/binary_oarchive.hpp>
+#include <boost/iostreams/stream_buffer.hpp>
+#include <boost/iostreams/stream.hpp>
+#include <boost/iostreams/device/back_inserter.hpp>
+#include "cryptonote_core/cryptonote_basic.h"
+#include "cryptonote_core/blockchain_storage.h"
+#include "cryptonote_core/blockchain.h"
+#include "blockchain_db/blockchain_db.h"
+#include "blockchain_db/lmdb/db_lmdb.h"
+
+// CONFIG: choose one of the three #define's
+//
+// DB_MEMORY is a sensible default for users migrating to LMDB, as it allows
+// the exporter to use the in-memory blockchain while the other binaries
+// work with LMDB, without recompiling anything.
+//
+#define SOURCE_DB DB_MEMORY
+// #define SOURCE_DB DB_LMDB
+// to use global compile-time setting (DB_MEMORY or DB_LMDB):
+// #define SOURCE_DB BLOCKCHAIN_DB
+
+using namespace cryptonote;
+
+class BlockchainExport
+{
+public:
+#if SOURCE_DB == DB_MEMORY
+  bool store_blockchain_raw(cryptonote::blockchain_storage* cs, cryptonote::tx_memory_pool* txp,
+      boost::filesystem::path& output_dir, uint64_t use_block_height=0);
+#else
+  bool store_blockchain_raw(cryptonote::Blockchain* cs, cryptonote::tx_memory_pool* txp,
+      boost::filesystem::path& output_dir, uint64_t use_block_height=0);
+#endif
+
+protected:
+#if SOURCE_DB == DB_MEMORY
+  blockchain_storage* m_blockchain_storage;
+#else
+  Blockchain* m_blockchain_storage;
+#endif
+
+  tx_memory_pool* m_tx_pool;
+  typedef std::vector<char> buffer_type;
+  std::ofstream * m_raw_data_file;
+  boost::archive::binary_oarchive * m_raw_archive;
+  buffer_type m_buffer;
+  boost::iostreams::stream<boost::iostreams::back_insert_device<buffer_type>>* m_output_stream;
+
+  // open export file for write
+  bool open(const boost::filesystem::path& dir_path);
+  bool close();
+  void write_block(block& block);
+  void serialize_block_to_text_buffer(const block& block);
+  void buffer_serialize_tx(const transaction& tx);
+  void buffer_write_num_txs(const std::list<transaction> txs);
+  void flush_chunk();
+};
diff --git a/src/blockchain_converter/blockchain_import.cpp b/src/blockchain_converter/blockchain_import.cpp
new file mode 100644
index 000000000..060fe8481
--- /dev/null
+++ b/src/blockchain_converter/blockchain_import.cpp
@@ -0,0 +1,751 @@
+// Copyright (c) 2014-2015, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <atomic>
+#include <cstdio>
+#include <algorithm>
+#include <fstream>
+
+#include <boost/filesystem.hpp>
+#include <boost/iostreams/stream.hpp>
+#include <boost/archive/binary_iarchive.hpp>
+#include "cryptonote_core/cryptonote_basic.h"
+#include "cryptonote_core/cryptonote_format_utils.h"
+#include "cryptonote_core/cryptonote_boost_serialization.h"
+#include "serialization/json_utils.h" // dump_json()
+#include "include_base_utils.h"
+#include "common/command_line.h"
+#include "version.h"
+
+#include <lmdb.h> // for db flag arguments
+
+#include "import.h"
+#include "fake_core.h"
+
+// CONFIG
+static bool opt_batch   = true;
+static bool opt_verify  = true; // use add_new_block, which does verification before calling add_block
+static bool opt_resume  = true;
+static bool opt_testnet = true;
+
+// number of blocks per batch transaction
+// adjustable through command-line argument according to available RAM
+static uint64_t db_batch_size = 20000;
+
+
+namespace po = boost::program_options;
+
+using namespace cryptonote;
+using namespace epee;
+
+
+int parse_db_arguments(const std::string& db_arg_str, std::string& db_engine, int& mdb_flags)
+{
+  std::vector<std::string> db_args;
+  boost::split(db_args, db_arg_str, boost::is_any_of("#"));
+  db_engine = db_args.front();
+  boost::algorithm::trim(db_engine);
+
+  if (db_args.size() == 1)
+  {
+    return 0;
+  }
+  else if (db_args.size() > 2)
+  {
+    std::cerr << "unrecognized database argument format: " << db_arg_str << ENDL;
+    return 1;
+  }
+
+  std::string db_arg_str2 = db_args[1];
+  boost::split(db_args, db_arg_str2, boost::is_any_of(","));
+  for (auto& it : db_args)
+  {
+    boost::algorithm::trim(it);
+    if (it.empty())
+      continue;
+    LOG_PRINT_L1("LMDB flag: " << it);
+    if (it == "nosync")
+    {
+      mdb_flags |= MDB_NOSYNC;
+    }
+    else if (it == "nometasync")
+    {
+      mdb_flags |= MDB_NOMETASYNC;
+    }
+    else if (it == "writemap")
+    {
+      mdb_flags |= MDB_WRITEMAP;
+    }
+    else if (it == "mapasync")
+    {
+      mdb_flags |= MDB_MAPASYNC;
+    }
+    else
+    {
+      std::cerr << "unrecognized database flag: " << it << ENDL;
+      return 1;
+    }
+  }
+  return 0;
+}
+
+
+int count_blocks(std::string& import_file_path)
+{
+  boost::filesystem::path raw_file_path(import_file_path);
+  boost::system::error_code ec;
+  if (!boost::filesystem::exists(raw_file_path, ec))
+  {
+    LOG_PRINT_L0("import file not found: " << raw_file_path);
+    throw std::runtime_error("Aborting");
+  }
+  std::ifstream import_file;
+  import_file.open(import_file_path, std::ios_base::binary | std::ifstream::in);
+
+  uint64_t h = 0;
+  if (import_file.fail())
+  {
+    LOG_PRINT_L0("import_file.open() fail");
+    throw std::runtime_error("Aborting");
+  }
+  LOG_PRINT_L0("Scanning blockchain from import file...");
+  char buffer1[STR_LENGTH_OF_INT + 1];
+  block b;
+  transaction tx;
+  bool quit = false;
+  uint64_t bytes_read = 0;
+  int progress_interval = 10;
+
+  while (! quit)
+  {
+    int chunk_size;
+    import_file.read(buffer1, STR_LENGTH_OF_INT);
+    if (!import_file) {
+      std::cout << "\r                   \r";
+      LOG_PRINT_L1("End of import file reached");
+      quit = true;
+      break;
+    }
+    h += NUM_BLOCKS_PER_CHUNK;
+    if (h % progress_interval == 0)
+    {
+      std::cout << "\r                   \r" << "block height: " << h <<
+        std::flush;
+    }
+    bytes_read += STR_LENGTH_OF_INT;
+    buffer1[STR_LENGTH_OF_INT] = '\0';
+    chunk_size = atoi(buffer1);
+    if (chunk_size > BUFFER_SIZE)
+    {
+      std::cout << "\r                   \r";
+      LOG_PRINT_L0("WARNING: chunk_size " << chunk_size << " > BUFFER_SIZE " << BUFFER_SIZE
+          << "  height: " << h);
+      throw std::runtime_error("Aborting: chunk size exceeds buffer size");
+    }
+    if (chunk_size > 100000)
+    {
+      std::cout << "\r                   \r";
+      LOG_PRINT_L0("WARNING: chunk_size " << chunk_size << " > 100000" << "  height: "
+          << h);
+    }
+    else if (chunk_size <= 0) {
+      std::cout << "\r                   \r";
+      LOG_PRINT_L0("ERROR: chunk_size " << chunk_size << " <= 0" << "  height: " << h);
+      throw std::runtime_error("Aborting");
+    }
+    // skip to next expected block size value
+    import_file.seekg(chunk_size, std::ios_base::cur);
+    if (! import_file) {
+      std::cout << "\r                   \r";
+      LOG_PRINT_L0("ERROR: unexpected end of import file: bytes read before error: "
+          << import_file.gcount() << " of chunk_size " << chunk_size);
+      throw std::runtime_error("Aborting");
+    }
+    bytes_read += chunk_size;
+    std::cout << "\r                   \r";
+    LOG_PRINT_L3("Total bytes scanned: " << bytes_read);
+  }
+
+  import_file.close();
+
+  std::cout << ENDL;
+  std::cout << "Done scanning import file" << ENDL;
+  std::cout << "Total bytes scanned: " << bytes_read << ENDL;
+  std::cout << "Height: " << h << ENDL;
+
+  return h;
+}
+
+template <typename FakeCore>
+int import_from_file(FakeCore& simple_core, std::string& import_file_path)
+{
+#if !defined(BLOCKCHAIN_DB)
+  static_assert(std::is_same<fake_core_memory, FakeCore>::value || std::is_same<fake_core_lmdb, FakeCore>::value,
+      "FakeCore constraint error");
+#endif
+#if !defined(BLOCKCHAIN_DB) || (BLOCKCHAIN_DB == DB_LMDB)
+  if (std::is_same<fake_core_lmdb, FakeCore>::value)
+  {
+    // Reset stats, in case we're using newly created db, accumulating stats
+    // from addition of genesis block.
+    // This aligns internal db counts with importer counts.
+    simple_core.m_storage.get_db()->reset_stats();
+  }
+#endif
+  boost::filesystem::path raw_file_path(import_file_path);
+  boost::system::error_code ec;
+  if (!boost::filesystem::exists(raw_file_path, ec))
+  {
+    LOG_PRINT_L0("import file not found: " << raw_file_path);
+    return false;
+  }
+
+  uint64_t source_height = count_blocks(import_file_path);
+  LOG_PRINT_L0("import file blockchain height: " << source_height);
+
+  std::ifstream import_file;
+  import_file.open(import_file_path, std::ios_base::binary | std::ifstream::in);
+
+  uint64_t h = 0;
+  if (import_file.fail())
+  {
+    LOG_PRINT_L0("import_file.open() fail");
+    return false;
+  }
+  char buffer1[STR_LENGTH_OF_INT + 1];
+  char buffer_block[BUFFER_SIZE];
+  block b;
+  transaction tx;
+  int quit = 0;
+  uint64_t bytes_read = 0;
+
+  uint64_t start_height = 1;
+  if (opt_resume)
+    start_height = simple_core.m_storage.get_current_blockchain_height();
+
+  // Note that a new blockchain will start with a height of 1 (block number 0)
+  // due to genesis block being added at initialization.
+
+  // CONFIG
+  // TODO: can expand on this, e.g. with --block-number option
+  uint64_t stop_height = source_height;
+
+  // These are what we'll try to use, and they don't have to be a determination
+  // from source and destination blockchains, but those are the current
+  // defaults.
+  LOG_PRINT_L0("start height: " << start_height << "  stop height: " <<
+      stop_height);
+
+  bool use_batch = false;
+  if (opt_batch)
+  {
+    if (simple_core.support_batch)
+      use_batch = true;
+    else
+      LOG_PRINT_L0("WARNING: batch transactions enabled but unsupported or unnecessary for this database engine - ignoring");
+  }
+
+  if (use_batch)
+    simple_core.batch_start();
+
+  LOG_PRINT_L0("Reading blockchain from import file...");
+  std::cout << ENDL;
+
+  // Within the loop, we skip to start_height before we start adding.
+  // TODO: Not a bottleneck, but we can use what's done in count_blocks() and
+  // only do the chunk size reads, skipping the chunk content reads until we're
+  // at start_height.
+  while (! quit)
+  {
+    int chunk_size;
+    import_file.read(buffer1, STR_LENGTH_OF_INT);
+    if (! import_file) {
+      std::cout << "\r                   \r";
+      LOG_PRINT_L0("End of import file reached");
+      quit = 1;
+      break;
+    }
+    bytes_read += STR_LENGTH_OF_INT;
+    buffer1[STR_LENGTH_OF_INT] = '\0';
+    chunk_size = atoi(buffer1);
+    if (chunk_size > BUFFER_SIZE)
+    {
+      LOG_PRINT_L0("WARNING: chunk_size " << chunk_size << " > BUFFER_SIZE " << BUFFER_SIZE);
+      throw std::runtime_error("Aborting: chunk size exceeds buffer size");
+    }
+    if (chunk_size > 100000)
+    {
+      LOG_PRINT_L0("WARNING: chunk_size " << chunk_size << " > 100000");
+    }
+    else if (chunk_size < 0) {
+      LOG_PRINT_L0("ERROR: chunk_size " << chunk_size << " < 0");
+      return 2;
+    }
+    import_file.read(buffer_block, chunk_size);
+    if (! import_file) {
+      LOG_PRINT_L0("ERROR: unexpected end of import file: bytes read before error: "
+          << import_file.gcount() << " of chunk_size " << chunk_size);
+      return 2;
+    }
+    bytes_read += chunk_size;
+    LOG_PRINT_L3("Total bytes read: " << bytes_read);
+
+    if (h + NUM_BLOCKS_PER_CHUNK < start_height + 1)
+    {
+      h += NUM_BLOCKS_PER_CHUNK;
+      continue;
+    }
+    if (h > stop_height)
+    {
+      LOG_PRINT_L0("Specified height reached - stopping.  height: " << h << "  block: " << h-1);
+      quit = 1;
+      break;
+    }
+
+    try
+    {
+      boost::iostreams::basic_array_source<char> device(buffer_block, chunk_size);
+      boost::iostreams::stream<boost::iostreams::basic_array_source<char>> s(device);
+      boost::archive::binary_iarchive a(s);
+
+      int display_interval = 1000;
+      int progress_interval = 10;
+      for (int chunk_ind = 0; chunk_ind < NUM_BLOCKS_PER_CHUNK; chunk_ind++)
+      {
+        h++;
+        if (h % display_interval == 0)
+        {
+          std::cout << "\r                   \r";
+          LOG_PRINT_L0("loading block height " << h);
+        }
+        else
+        {
+          LOG_PRINT_L3("loading block height " << h);
+        }
+        try {
+          a >> b;
+        }
+        catch (const std::exception& e)
+        {
+          std::cout << "\r                   \r";
+          LOG_PRINT_RED_L0("exception while de-archiving block, height=" << h);
+          quit = 1;
+          break;
+        }
+        LOG_PRINT_L2("block prev_id: " << b.prev_id << ENDL);
+
+        if (h % progress_interval == 0)
+        {
+          std::cout << "\r                   \r" << "block " << h-1
+            << std::flush;
+        }
+
+        std::vector<transaction> txs;
+
+        int num_txs;
+        try
+        {
+          a >> num_txs;
+        }
+        catch (const std::exception& e)
+        {
+          std::cout << "\r                   \r";
+          LOG_PRINT_RED_L0("exception while de-archiving tx-num, height=" << h);
+          quit = 1;
+          break;
+        }
+        for(int tx_num = 1; tx_num <= num_txs; tx_num++)
+        {
+          try {
+                a >> tx;
+          }
+          catch (const std::exception& e)
+          {
+            LOG_PRINT_RED_L0("exception while de-archiving tx, height=" << h <<", tx_num=" << tx_num);
+            quit = 1;
+            break;
+          }
+          // if (tx_num == 1) {
+          //   std::cout << "coinbase transaction" << ENDL;
+          // }
+          // crypto::hash hsh = null_hash;
+          // size_t blob_size = 0;
+          // NOTE: all tx hashes except for coinbase tx are available in the block data
+          // get_transaction_hash(tx, hsh, blob_size);
+          // LOG_PRINT_L0("tx " << tx_num << "  " << hsh << " : " << ENDL);
+          // LOG_PRINT_L0(obj_to_json_str(tx) << ENDL);
+
+          // add blocks with verification.
+          // for Blockchain and blockchain_storage add_new_block().
+          if (opt_verify)
+          {
+            if (tx_num == 1) {
+              continue; // coinbase transaction. no need to insert to tx_pool.
+            }
+            // crypto::hash hsh = null_hash;
+            // size_t blob_size = 0;
+            // get_transaction_hash(tx, hsh, blob_size);
+            tx_verification_context tvc = AUTO_VAL_INIT(tvc);
+            bool r = true;
+            r = simple_core.m_pool.add_tx(tx, tvc, true);
+            if (!r)
+            {
+              LOG_PRINT_RED_L0("failed to add transaction to transaction pool, height=" << h <<", tx_num=" << tx_num);
+              quit = 1;
+              break;
+            }
+          }
+          else
+          {
+            // for add_block() method, without (much) processing.
+            // don't add coinbase transaction to txs.
+            //
+            // because add_block() calls
+            // add_transaction(blk_hash, blk.miner_tx) first, and
+            // then a for loop for the transactions in txs.
+            if (tx_num > 1)
+            {
+              txs.push_back(tx);
+            }
+          }
+        }
+
+        if (opt_verify)
+        {
+          block_verification_context bvc = boost::value_initialized<block_verification_context>();
+          simple_core.m_storage.add_new_block(b, bvc);
+
+          if (bvc.m_verifivation_failed)
+          {
+            LOG_PRINT_L0("Failed to add block to blockchain, verification failed, height = " << h);
+            LOG_PRINT_L0("skipping rest of import file");
+            // ok to commit previously batched data because it failed only in
+            // verification of potential new block with nothing added to batch
+            // yet
+            quit = 1;
+            break;
+          }
+          if (! bvc.m_added_to_main_chain)
+          {
+            LOG_PRINT_L0("Failed to add block to blockchain, height = " << h);
+            LOG_PRINT_L0("skipping rest of import file");
+            // make sure we don't commit partial block data
+            quit = 2;
+            break;
+          }
+        }
+        else
+        {
+          size_t block_size;
+          difficulty_type cumulative_difficulty;
+          uint64_t coins_generated;
+
+          a >> block_size;
+          a >> cumulative_difficulty;
+          a >> coins_generated;
+
+          std::cout << "\r                   \r";
+          LOG_PRINT_L2("block_size: " << block_size);
+          LOG_PRINT_L2("cumulative_difficulty: " << cumulative_difficulty);
+          LOG_PRINT_L2("coins_generated: " << coins_generated);
+
+          try
+          {
+            simple_core.add_block(b, block_size, cumulative_difficulty, coins_generated, txs);
+          }
+          catch (const std::exception& e)
+          {
+            std::cout << "\r                   \r";
+            LOG_PRINT_RED_L0("Error adding block to blockchain: " << e.what());
+            quit = 2; // make sure we don't commit partial block data
+            break;
+          }
+        }
+
+        if (use_batch)
+        {
+          if (h % db_batch_size == 0)
+          {
+            std::cout << "\r                   \r";
+            std::cout << ENDL << "[- batch commit at height " << h << " -]" << ENDL;
+            simple_core.batch_stop();
+            simple_core.batch_start();
+            std::cout << ENDL;
+#if !defined(BLOCKCHAIN_DB) || (BLOCKCHAIN_DB == DB_LMDB)
+            simple_core.m_storage.get_db()->show_stats();
+#endif
+          }
+        }
+      }
+    }
+    catch (const std::exception& e)
+    {
+      std::cout << "\r                   \r";
+      LOG_PRINT_RED_L0("exception while reading from import file, height=" << h);
+      return 2;
+    }
+  } // while
+
+  import_file.close();
+
+  if (use_batch)
+  {
+    if (quit > 1)
+    {
+      // There was an error, so don't commit pending data.
+      // Destructor will abort write txn.
+    }
+    else
+    {
+      simple_core.batch_stop();
+    }
+#if !defined(BLOCKCHAIN_DB) || (BLOCKCHAIN_DB == DB_LMDB)
+    simple_core.m_storage.get_db()->show_stats();
+#endif
+    if (h > 0)
+      LOG_PRINT_L0("Finished at height: " << h << "  block: " << h-1);
+  }
+  std::cout << ENDL;
+  return 0;
+}
+
+int main(int argc, char* argv[])
+{
+  std::string import_filename = BLOCKCHAIN_RAW;
+#if defined(BLOCKCHAIN_DB) && (BLOCKCHAIN_DB == DB_MEMORY)
+  std::string default_db_engine = "memory";
+#else
+  std::string default_db_engine = "lmdb";
+#endif
+
+  uint32_t log_level = LOG_LEVEL_0;
+  std::string dirname;
+  std::string db_arg_str;
+
+  boost::filesystem::path default_data_path {tools::get_default_data_dir()};
+  boost::filesystem::path default_testnet_data_path {default_data_path / "testnet"};
+
+  po::options_description desc_cmd_only("Command line options");
+  po::options_description desc_cmd_sett("Command line options and settings options");
+  const command_line::arg_descriptor<uint32_t> arg_log_level   =  {"log-level",  "", log_level};
+  const command_line::arg_descriptor<uint64_t> arg_batch_size  =  {"batch-size", "", db_batch_size};
+  const command_line::arg_descriptor<bool>     arg_testnet_on  = {
+    "testnet"
+      , "Run on testnet."
+      , false
+  };
+  const command_line::arg_descriptor<bool>     arg_count_blocks = {
+    "count-blocks"
+      , "Count blocks in import file and exit"
+      , false
+  };
+  const command_line::arg_descriptor<std::string> arg_database = {
+    "database", "available: memory, lmdb"
+      , default_db_engine
+  };
+  const command_line::arg_descriptor<bool> arg_verify =  {"verify",
+    "Verify blocks and transactions during import", true};
+  const command_line::arg_descriptor<bool> arg_batch  =  {"batch",
+    "Batch transactions for faster import", true};
+  const command_line::arg_descriptor<bool> arg_resume =  {"resume",
+    "Resume from current height if output database already exists", true};
+
+  command_line::add_arg(desc_cmd_sett, command_line::arg_data_dir, default_data_path.string());
+  command_line::add_arg(desc_cmd_sett, command_line::arg_testnet_data_dir, default_testnet_data_path.string());
+  command_line::add_arg(desc_cmd_sett, arg_log_level);
+  command_line::add_arg(desc_cmd_sett, arg_batch_size);
+  command_line::add_arg(desc_cmd_sett, arg_testnet_on);
+  command_line::add_arg(desc_cmd_sett, arg_database);
+
+  command_line::add_arg(desc_cmd_only, arg_count_blocks);
+  command_line::add_arg(desc_cmd_only, command_line::arg_help);
+
+  // call add_options() directly for these arguments since
+  // command_line helpers support only boolean switch, not boolean argument
+  desc_cmd_sett.add_options()
+    (arg_verify.name, make_semantic(arg_verify), arg_verify.description)
+    (arg_batch.name,  make_semantic(arg_batch),  arg_batch.description)
+    (arg_resume.name, make_semantic(arg_resume), arg_resume.description)
+    ;
+
+  po::options_description desc_options("Allowed options");
+  desc_options.add(desc_cmd_only).add(desc_cmd_sett);
+
+  po::variables_map vm;
+  bool r = command_line::handle_error_helper(desc_options, [&]()
+  {
+    po::store(po::parse_command_line(argc, argv, desc_options), vm);
+    po::notify(vm);
+    return true;
+  });
+  if (! r)
+    return 1;
+
+  log_level     = command_line::get_arg(vm, arg_log_level);
+  opt_verify    = command_line::get_arg(vm, arg_verify);
+  opt_batch     = command_line::get_arg(vm, arg_batch);
+  opt_resume    = command_line::get_arg(vm, arg_resume);
+  db_batch_size = command_line::get_arg(vm, arg_batch_size);
+
+  if (command_line::get_arg(vm, command_line::arg_help))
+  {
+    std::cout << CRYPTONOTE_NAME << " v" << MONERO_VERSION_FULL << ENDL << ENDL;
+    std::cout << desc_options << std::endl;
+    return 1;
+  }
+
+  if (! opt_batch && ! vm["batch-size"].defaulted())
+  {
+    std::cerr << "Error: batch-size set, but batch option not enabled" << ENDL;
+    exit(1);
+  }
+  if (! db_batch_size)
+  {
+    std::cerr << "Error: batch-size must be > 0" << ENDL;
+    exit(1);
+  }
+
+  std::vector<std::string> db_engines {"memory", "lmdb"};
+
+  opt_testnet = command_line::get_arg(vm, arg_testnet_on);
+  auto data_dir_arg = opt_testnet ? command_line::arg_testnet_data_dir : command_line::arg_data_dir;
+  dirname = command_line::get_arg(vm, data_dir_arg);
+  db_arg_str = command_line::get_arg(vm, arg_database);
+
+  log_space::get_set_log_detalisation_level(true, log_level);
+  log_space::log_singletone::add_logger(LOGGER_CONSOLE, NULL, NULL);
+  LOG_PRINT_L0("Starting...");
+  LOG_PRINT_L0("Setting log level = " << log_level);
+
+  boost::filesystem::path file_path {dirname};
+  std::string import_file_path;
+
+  import_file_path = (file_path / "export" / import_filename).string();
+
+  if (command_line::has_arg(vm, arg_count_blocks))
+  {
+    count_blocks(import_file_path);
+    exit(0);
+  }
+
+
+  std::string db_engine;
+  int mdb_flags = 0;
+  int res = 0;
+  res = parse_db_arguments(db_arg_str, db_engine, mdb_flags);
+  if (res)
+  {
+    std::cerr << "Error parsing database argument(s)" << ENDL;
+    exit(1);
+  }
+
+  if (std::find(db_engines.begin(), db_engines.end(), db_engine) == db_engines.end())
+  {
+    std::cerr << "Invalid database engine: " << db_engine << std::endl;
+    exit(1);
+  }
+
+  LOG_PRINT_L0("database: " << db_engine);
+  LOG_PRINT_L0("verify:  " << std::boolalpha << opt_verify << std::noboolalpha);
+  if (opt_batch)
+  {
+    LOG_PRINT_L0("batch:   " << std::boolalpha << opt_batch << std::noboolalpha
+        << "  batch size: " << db_batch_size);
+  }
+  else
+  {
+    LOG_PRINT_L0("batch:   " << std::boolalpha << opt_batch << std::noboolalpha);
+  }
+  LOG_PRINT_L0("resume:  " << std::boolalpha << opt_resume  << std::noboolalpha);
+  LOG_PRINT_L0("testnet: " << std::boolalpha << opt_testnet << std::noboolalpha);
+
+  std::cout << "import file path: " << import_file_path << ENDL;
+  std::cout << "database path:    " << file_path.string() << ENDL;
+
+  try
+  {
+
+  // fake_core needed for verification to work when enabled.
+  //
+  // NOTE: don't need fake_core method of doing things when we're going to call
+  // BlockchainDB add_block() directly and have available the 3 block
+  // properties to do so. Both ways work, but fake core isn't necessary in that
+  // circumstance.
+
+  // for multi_db_runtime:
+#if !defined(BLOCKCHAIN_DB)
+  if (db_engine == "lmdb")
+  {
+    fake_core_lmdb simple_core(dirname, opt_testnet, opt_batch, mdb_flags);
+    import_from_file(simple_core, import_file_path);
+  }
+  else if (db_engine == "memory")
+  {
+    fake_core_memory simple_core(dirname, opt_testnet);
+    import_from_file(simple_core, import_file_path);
+  }
+  else
+  {
+    std::cerr << "database engine unrecognized" << ENDL;
+    exit(1);
+  }
+
+  // for multi_db_compile:
+#else
+  if (db_engine != default_db_engine)
+  {
+    std::cerr << "Invalid database engine for compiled version: " << db_engine << std::endl;
+    exit(1);
+  }
+#if BLOCKCHAIN_DB == DB_LMDB
+  fake_core_lmdb simple_core(dirname, opt_testnet, opt_batch, mdb_flags);
+#else
+  fake_core_memory simple_core(dirname, opt_testnet);
+#endif
+
+  import_from_file(simple_core, import_file_path);
+#endif
+
+  }
+  catch (const DB_ERROR& e)
+  {
+    std::cout << std::string("Error loading blockchain db: ") + e.what() + " -- shutting down now" << ENDL;
+    exit(1);
+  }
+
+  // destructors called at exit:
+  //
+  // ensure db closed
+  //   - transactions properly checked and handled
+  //   - disk sync if needed
+  //
+  // fake_core object's destructor is called when it goes out of scope. For an
+  // LMDB fake_core, it calls Blockchain::deinit() on its object, which in turn
+  // calls delete on its BlockchainDB derived class' object, which closes its
+  // files.
+}
diff --git a/src/blockchain_converter/fake_core.h b/src/blockchain_converter/fake_core.h
new file mode 100644
index 000000000..aff249cd9
--- /dev/null
+++ b/src/blockchain_converter/fake_core.h
@@ -0,0 +1,143 @@
+// Copyright (c) 2014-2015, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+#include <boost/filesystem.hpp>
+#include "cryptonote_core/blockchain.h" // BlockchainDB and LMDB
+#include "cryptonote_core/blockchain_storage.h" // in-memory DB
+
+using namespace cryptonote;
+
+
+#if !defined(BLOCKCHAIN_DB) || BLOCKCHAIN_DB == DB_LMDB
+
+struct fake_core_lmdb
+{
+  Blockchain m_storage;
+  tx_memory_pool m_pool;
+  bool support_batch;
+  bool support_add_block;
+
+  // for multi_db_runtime:
+#if !defined(BLOCKCHAIN_DB)
+  fake_core_lmdb(const boost::filesystem::path &path, const bool use_testnet=false, const bool do_batch=true, const int mdb_flags=0) : m_pool(&m_storage), m_storage(m_pool)
+  // for multi_db_compile:
+#else
+  fake_core_lmdb(const boost::filesystem::path &path, const bool use_testnet=false, const bool do_batch=true, const int mdb_flags=0) : m_pool(m_storage), m_storage(m_pool)
+#endif
+  {
+    m_pool.init(path.string());
+    m_storage.init(path.string(), use_testnet, mdb_flags);
+    if (do_batch)
+      m_storage.get_db()->set_batch_transactions(do_batch);
+    support_batch = true;
+    support_add_block = true;
+  }
+  ~fake_core_lmdb()
+  {
+    m_storage.deinit();
+  }
+
+  uint64_t add_block(const block& blk
+                            , const size_t& block_size
+                            , const difficulty_type& cumulative_difficulty
+                            , const uint64_t& coins_generated
+                            , const std::vector<transaction>& txs
+                            )
+  {
+    return m_storage.get_db()->add_block(blk, block_size, cumulative_difficulty, coins_generated, txs);
+  }
+
+  void batch_start()
+  {
+    m_storage.get_db()->batch_start();
+  }
+
+  void batch_stop()
+  {
+    m_storage.get_db()->batch_stop();
+  }
+
+};
+#endif
+
+#if !defined(BLOCKCHAIN_DB) || BLOCKCHAIN_DB == DB_MEMORY
+
+struct fake_core_memory
+{
+  blockchain_storage m_storage;
+  tx_memory_pool m_pool;
+  bool support_batch;
+  bool support_add_block;
+
+  // for multi_db_runtime:
+#if !defined(BLOCKCHAIN_DB)
+  fake_core_memory(const boost::filesystem::path &path, const bool use_testnet=false) : m_pool(&m_storage), m_storage(m_pool)
+#else
+  // for multi_db_compile:
+  fake_core_memory(const boost::filesystem::path &path, const bool use_testnet=false) : m_pool(m_storage), m_storage(&m_pool)
+#endif
+  {
+    m_pool.init(path.string());
+    m_storage.init(path.string(), use_testnet);
+    support_batch = false;
+    support_add_block = false;
+  }
+  ~fake_core_memory()
+  {
+    LOG_PRINT_L3("fake_core_memory() destructor called - want to see it ripple down");
+    m_storage.deinit();
+  }
+
+  uint64_t add_block(const block& blk
+                            , const size_t& block_size
+                            , const difficulty_type& cumulative_difficulty
+                            , const uint64_t& coins_generated
+                            , const std::vector<transaction>& txs
+                            )
+  {
+    // TODO:
+    // would need to refactor handle_block_to_main_chain() to have a direct add_block() method like Blockchain class
+    throw std::runtime_error("direct add_block() method not implemented for in-memory db");
+    return 2;
+  }
+
+  void batch_start()
+  {
+    LOG_PRINT_L0("WARNING: [batch_start] opt_batch set, but this database doesn't support/need transactions - ignoring");
+  }
+
+  void batch_stop()
+  {
+    LOG_PRINT_L0("WARNING: [batch_stop] opt_batch set, but this database doesn't support/need transactions - ignoring");
+  }
+
+};
+
+#endif
diff --git a/src/blockchain_converter/import.h b/src/blockchain_converter/import.h
new file mode 100644
index 000000000..632b4c0d9
--- /dev/null
+++ b/src/blockchain_converter/import.h
@@ -0,0 +1,37 @@
+// Copyright (c) 2014-2015, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+// TODO: bounds checking is done before writing to buffer, but buffer size
+// should be a sensible maximum
+#define BUFFER_SIZE 1000000
+#define NUM_BLOCKS_PER_CHUNK 1
+#define STR_LENGTH_OF_INT 9
+#define STR_FORMAT_OF_INT "%09d"
+#define BLOCKCHAIN_RAW "blockchain.raw"
diff --git a/src/blockchain_db/blockchain_db.h b/src/blockchain_db/blockchain_db.h
index d2b4a07a7..7b6b55a40 100644
--- a/src/blockchain_db/blockchain_db.h
+++ b/src/blockchain_db/blockchain_db.h
@@ -326,7 +326,7 @@ public:
   void show_stats();
 
   // open the db at location <filename>, or create it if there isn't one.
-  virtual void open(const std::string& filename) = 0;
+  virtual void open(const std::string& filename, const int db_flags = 0) = 0;
 
   // make sure implementation has a create function as well
   virtual void create(const std::string& filename) = 0;
diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index 1fd039905..524a1c269 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -149,6 +149,20 @@ inline void lmdb_db_open(MDB_txn* txn, const char* name, int flags, MDB_dbi& dbi
 namespace cryptonote
 {
 
+// If m_batch_active is set, a batch transaction exists beyond this class, such
+// as a batch import with verification enabled, or possibly (later) a batch
+// network sync.
+//
+// For some of the lookup methods, such as get_block_timestamp(), tx_exists(),
+// and get_tx(), when m_batch_active is set, the lookup uses the batch
+// transaction. This isn't only because the transaction is available, but it's
+// necessary so that lookups include the database updates only present in the
+// current batch write.
+//
+// A regular network sync without batch writes is expected to open a new read
+// transaction, as those lookups are part of the validation done prior to the
+// write for block and tx data, so no write transaction is open at the time.
+
 void BlockchainLMDB::add_block( const block& blk
               , const size_t& block_size
               , const difficulty_type& cumulative_difficulty
@@ -621,7 +635,7 @@ BlockchainLMDB::BlockchainLMDB(bool batch_transactions)
   m_height = 0;
 }
 
-void BlockchainLMDB::open(const std::string& filename)
+void BlockchainLMDB::open(const std::string& filename, const int mdb_flags)
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
 
@@ -661,7 +675,7 @@ void BlockchainLMDB::open(const std::string& filename)
   size_t mapsize = 1LL << 34;
   if (auto result = mdb_env_set_mapsize(m_env, mapsize))
     throw0(DB_ERROR(std::string("Failed to set max memory map size: ").append(mdb_strerror(result)).c_str()));
-  if (auto result = mdb_env_open(m_env, filename.c_str(), 0, 0644))
+  if (auto result = mdb_env_open(m_env, filename.c_str(), mdb_flags, 0644))
     throw0(DB_ERROR(std::string("Failed to open lmdb environment: ").append(mdb_strerror(result)).c_str()));
 
   // get a read/write MDB_txn
@@ -1260,14 +1274,6 @@ uint64_t BlockchainLMDB::get_tx_block_height(const crypto::hash& h) const
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
   check_open();
 
-  // If m_batch_active is set, a batch transaction exists beyond this class,
-  // such as a batch import with verification enabled, or possibly (later) a
-  // batch network sync.
-  //
-  // A regular network sync without batching would be expected to open a new
-  // read transaction here, as validation is done prior to the write for block
-  // and tx data.
-
   mdb_txn_safe txn;
   mdb_txn_safe* txn_ptr = &txn;
   if (m_batch_active)
diff --git a/src/blockchain_db/lmdb/db_lmdb.h b/src/blockchain_db/lmdb/db_lmdb.h
index a04d0f6b4..c3c7ce439 100644
--- a/src/blockchain_db/lmdb/db_lmdb.h
+++ b/src/blockchain_db/lmdb/db_lmdb.h
@@ -114,7 +114,7 @@ public:
   BlockchainLMDB(bool batch_transactions=false);
   ~BlockchainLMDB();
 
-  virtual void open(const std::string& filename);
+  virtual void open(const std::string& filename, const int mdb_flags=0);
 
   virtual void create(const std::string& filename);
 
diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index b7920c99c..57934b3fc 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -226,7 +226,7 @@ uint64_t Blockchain::get_current_blockchain_height() const
 //------------------------------------------------------------------
 //FIXME: possibly move this into the constructor, to avoid accidentally
 //       dereferencing a null BlockchainDB pointer
-bool Blockchain::init(const std::string& config_folder, bool testnet)
+bool Blockchain::init(const std::string& config_folder, const bool testnet, const int db_flags)
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
   CRITICAL_REGION_LOCAL(m_blockchain_lock);
@@ -246,7 +246,7 @@ bool Blockchain::init(const std::string& config_folder, bool testnet)
   const std::string filename = folder.string();
   try
   {
-    m_db->open(filename);
+    m_db->open(filename, db_flags);
   }
   catch (const DB_OPEN_FAILURE& e)
   {
diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h
index 477aa4964..da4da075b 100644
--- a/src/cryptonote_core/blockchain.h
+++ b/src/cryptonote_core/blockchain.h
@@ -81,7 +81,7 @@ namespace cryptonote
 
     Blockchain(tx_memory_pool& tx_pool);
 
-    bool init(const std::string& config_folder, bool testnet = false);
+    bool init(const std::string& config_folder, const bool testnet = false, const int db_flags = 0);
     bool deinit();
 
     void set_checkpoints(checkpoints&& chk_pts) { m_checkpoints = chk_pts; }
@@ -145,6 +145,11 @@ namespace cryptonote
     void set_enforce_dns_checkpoints(bool enforce);
     bool update_checkpoints(const std::string& file_path, bool check_dns);
 
+    BlockchainDB* get_db()
+    {
+      return m_db;
+    }
+
   private:
     typedef std::unordered_map<crypto::hash, size_t> blocks_by_id_index;
     typedef std::unordered_map<crypto::hash, transaction_chain_entry> transactions_container;