Pruning

The blockchain prunes seven eighths of prunable tx data.
This saves about two thirds of the blockchain size, while
keeping the node useful as a sync source for an eighth
of the blockchain.

No other data is currently pruned.

There are three ways to prune a blockchain:

- run monerod with --prune-blockchain
- run "prune_blockchain" in the monerod console
- run the monero-blockchain-prune utility

The first two will prune in place. Due to how LMDB works, this
will not reduce the blockchain size on disk. Instead, it will
mark parts of the file as free, so that future data will use
that free space, causing the file to not grow until free space
grows scarce.

The third way will create a second database, a pruned copy of
the original one. Since this is a new file, this one will be
smaller than the original one.

Once the database is pruned, it will stay pruned as it syncs.
That is, there is no need to use --prune-blockchain again, etc.

1 files changed, 23 insertions, 0 deletions

diff --git a/src/daemon/command_parser_executor.cpp b/src/daemon/command_parser_executor.cpp
index b5b747e97..37cb55ec8 100644
--- a/src/daemon/command_parser_executor.cpp
+++ b/src/daemon/command_parser_executor.cpp
@@ -717,4 +717,27 @@ bool t_command_parser_executor::version(const std::vector<std::string>& args)
   return true;
 }
 
+bool t_command_parser_executor::prune_blockchain(const std::vector<std::string>& args)
+{
+  if (args.size() > 1) return false;
+
+  if (args.empty() || args[0] != "confirm")
+  {
+    std::cout << "Warning: pruning from within monerod will not shrink the database file size." << std::endl;
+    std::cout << "Instead, parts of the file will be marked as free, so the file will not grow" << std::endl;
+    std::cout << "until that newly free space is used up. If you want a smaller file size now," << std::endl;
+    std::cout << "exit monerod and run monero-blockchain-prune (you will temporarily need more" << std::endl;
+    std::cout << "disk space for the database conversion though). If you are OK with the database" << std::endl;
+    std::cout << "file keeping the same size, re-run this command with the \"confirm\" parameter." << std::endl;
+    return true;
+  }
+
+  return m_executor.prune_blockchain();
+}
+
+bool t_command_parser_executor::check_blockchain_pruning(const std::vector<std::string>& args)
+{
+  return m_executor.check_blockchain_pruning();
+}
+
 } // namespace daemonize