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, 11 insertions, 4 deletions

diff --git a/src/cryptonote_basic/cryptonote_basic.h b/src/cryptonote_basic/cryptonote_basic.h
index 196b20e2a..c9c783a56 100644
--- a/src/cryptonote_basic/cryptonote_basic.h
+++ b/src/cryptonote_basic/cryptonote_basic.h
@@ -201,9 +201,11 @@ namespace cryptonote
     mutable crypto::hash hash;
     mutable size_t blob_size;
 
+    bool pruned;
+
     transaction();
-    transaction(const transaction &t): transaction_prefix(t), hash_valid(false), blob_size_valid(false), signatures(t.signatures), rct_signatures(t.rct_signatures) { if (t.is_hash_valid()) { hash = t.hash; set_hash_valid(true); } if (t.is_blob_size_valid()) { blob_size = t.blob_size; set_blob_size_valid(true); } }
-    transaction &operator=(const transaction &t) { transaction_prefix::operator=(t); set_hash_valid(false); set_blob_size_valid(false); signatures = t.signatures; rct_signatures = t.rct_signatures; if (t.is_hash_valid()) { hash = t.hash; set_hash_valid(true); } if (t.is_blob_size_valid()) { blob_size = t.blob_size; set_blob_size_valid(true); } return *this; }
+    transaction(const transaction &t): transaction_prefix(t), hash_valid(false), blob_size_valid(false), signatures(t.signatures), rct_signatures(t.rct_signatures), pruned(t.pruned) { if (t.is_hash_valid()) { hash = t.hash; set_hash_valid(true); } if (t.is_blob_size_valid()) { blob_size = t.blob_size; set_blob_size_valid(true); } }
+    transaction &operator=(const transaction &t) { transaction_prefix::operator=(t); set_hash_valid(false); set_blob_size_valid(false); signatures = t.signatures; rct_signatures = t.rct_signatures; if (t.is_hash_valid()) { hash = t.hash; set_hash_valid(true); } if (t.is_blob_size_valid()) { blob_size = t.blob_size; set_blob_size_valid(true); } pruned = t.pruned; return *this; }
     virtual ~transaction();
     void set_null();
     void invalidate_hashes();
@@ -232,7 +234,7 @@ namespace cryptonote
         if (!signatures_not_expected && vin.size() != signatures.size())
           return false;
 
-        for (size_t i = 0; i < vin.size(); ++i)
+        if (!pruned) for (size_t i = 0; i < vin.size(); ++i)
         {
           size_t signature_size = get_signature_size(vin[i]);
           if (signatures_not_expected)
@@ -263,7 +265,7 @@ namespace cryptonote
           bool r = rct_signatures.serialize_rctsig_base(ar, vin.size(), vout.size());
           if (!r || !ar.stream().good()) return false;
           ar.end_object();
-          if (rct_signatures.type != rct::RCTTypeNull)
+          if (!pruned && rct_signatures.type != rct::RCTTypeNull)
           {
             ar.tag("rctsig_prunable");
             ar.begin_object();
@@ -274,6 +276,8 @@ namespace cryptonote
           }
         }
       }
+      if (!typename Archive<W>::is_saving())
+        pruned = false;
     END_SERIALIZE()
 
     template<bool W, template <bool> class Archive>
@@ -295,6 +299,8 @@ namespace cryptonote
           ar.end_object();
         }
       }
+      if (!typename Archive<W>::is_saving())
+        pruned = true;
       return true;
     }
 
@@ -322,6 +328,7 @@ namespace cryptonote
     rct_signatures.type = rct::RCTTypeNull;
     set_hash_valid(false);
     set_blob_size_valid(false);
+    pruned = false;
   }
 
   inline