From cd972bdcc25e9ed1d4c5bc7663242afa6a61125e Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Tue, 10 Feb 2015 19:54:27 -0800
Subject: [PATCH 01/16] Update year and formatting in license

---
 src/blockchain_converter/blockchain_converter.cpp | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/blockchain_converter/blockchain_converter.cpp b/src/blockchain_converter/blockchain_converter.cpp
index 57822700f..0dfc1a2c3 100644
--- a/src/blockchain_converter/blockchain_converter.cpp
+++ b/src/blockchain_converter/blockchain_converter.cpp
@@ -1,21 +1,21 @@
-// 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
 // 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

From 59305d3137cbf477c2dc07c26b757d23729ad72b Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Tue, 10 Feb 2015 15:25:15 -0800
Subject: [PATCH 02/16] Blockchain: match original function declaration from
 blockchain_storage

---
 src/cryptonote_core/blockchain.cpp | 2 +-
 src/cryptonote_core/blockchain.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 525c7f36e..b4b1a4c86 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -2288,7 +2288,7 @@ bool Blockchain::add_new_block(const block& bl_, block_verification_context& bvc
   return handle_block_to_main_chain(bl, id, bvc);
 }
 //------------------------------------------------------------------
-void Blockchain::check_against_checkpoints(checkpoints& points, bool enforce)
+void Blockchain::check_against_checkpoints(const checkpoints& points, bool enforce)
 {
   const auto& pts = points.get_points();
 
diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h
index 6ab963ac7..3e8a2de31 100644
--- a/src/cryptonote_core/blockchain.h
+++ b/src/cryptonote_core/blockchain.h
@@ -141,7 +141,7 @@ namespace cryptonote
     void print_blockchain_index();
     void print_blockchain_outs(const std::string& file);
 
-    void check_against_checkpoints(checkpoints& points, bool enforce);
+    void check_against_checkpoints(const checkpoints& points, bool enforce);
     void set_enforce_dns_checkpoints(bool enforce);
     bool update_checkpoints(const std::string& file_path, bool check_dns);
 

From 2531aa31f80dff871b08371324a43e1363218c59 Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Wed, 11 Feb 2015 15:55:53 -0800
Subject: [PATCH 03/16] Add and extend log statements

---
 .../BlockchainDB_impl/db_lmdb.cpp                | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index 4fa16b23e..f5368d6e5 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -167,8 +167,11 @@ void BlockchainLMDB::add_block( const block& blk
     MDB_val_copy<crypto::hash> parent_key(blk.prev_id);
     MDB_val parent_h;
     if (mdb_get(*m_write_txn, m_block_heights, &parent_key, &parent_h))
+    {
+      LOG_PRINT_L3("m_height: " << m_height);
+      LOG_PRINT_L3("parent_key: " << blk.prev_id);
       throw0(DB_ERROR("Failed to get top block hash to check for new block's parent"));
-
+    }
     uint64_t parent_height = *(const uint64_t *)parent_h.mv_data;
     if (parent_height != m_height - 1)
       throw0(BLOCK_PARENT_DNE("Top block is not new block's parent"));
@@ -177,8 +180,9 @@ void BlockchainLMDB::add_block( const block& blk
   MDB_val_copy<uint64_t> key(m_height);
 
   MDB_val_copy<blobdata> blob(block_to_blob(blk));
-  if (mdb_put(*m_write_txn, m_blocks, &key, &blob, 0))
-    throw0(DB_ERROR("Failed to add block blob to db transaction"));
+  auto res = mdb_put(*m_write_txn, m_blocks, &key, &blob, 0);
+  if (res)
+    throw0(DB_ERROR(std::string("Failed to add block blob to db transaction: ").append(mdb_strerror(res)).c_str()));
 
   MDB_val_copy<size_t> sz(block_size);
   if (mdb_put(*m_write_txn, m_block_sizes, &key, &sz, 0))
@@ -505,8 +509,8 @@ void BlockchainLMDB::add_spent_key(const crypto::key_image& k_image)
   char anything = '\0';
   unused.mv_size = sizeof(char);
   unused.mv_data = &anything;
-  if (mdb_put(*m_write_txn, m_spent_keys, &val_key, &unused, 0))
-      throw1(DB_ERROR("Error adding spent key image to db transaction"));
+  if (auto result = mdb_put(*m_write_txn, m_spent_keys, &val_key, &unused, 0))
+    throw1(DB_ERROR(std::string("Error adding spent key image to db transaction: ").append(mdb_strerror(result)).c_str()));
 }
 
 void BlockchainLMDB::remove_spent_key(const crypto::key_image& k_image)
@@ -910,7 +914,7 @@ size_t BlockchainLMDB::get_block_size(const uint64_t& height) const
 
 difficulty_type BlockchainLMDB::get_block_cumulative_difficulty(const uint64_t& height) const
 {
-  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__ << "  height: " << height);
   check_open();
 
   txn_safe txn;

From 4b90fd389de915767b89c558d7ec8187a5d61d14 Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Wed, 11 Feb 2015 15:55:53 -0800
Subject: [PATCH 04/16] Add log statement

---
 src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index f5368d6e5..b748baddb 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -1563,6 +1563,7 @@ uint64_t BlockchainLMDB::add_block( const block& blk
 
 void BlockchainLMDB::pop_block(block& blk, std::vector<transaction>& txs)
 {
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
   txn_safe txn;
   if (mdb_txn_begin(m_env, NULL, 0, txn))
     throw0(DB_ERROR("Failed to create a transaction for the db"));

From 26873db199198bad1892b17a9e7bc0a72c16d5b5 Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Wed, 11 Feb 2015 15:55:53 -0800
Subject: [PATCH 05/16] Remove unused variable

---
 src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index b748baddb..c9741c81d 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -386,7 +386,6 @@ void BlockchainLMDB::remove_output(const uint64_t& out_index, const uint64_t amo
   check_open();
 
   MDB_val_copy<uint64_t> k(out_index);
-  MDB_val v;
 
 /****** Uncomment if ever outputs actually need to be stored in this manner
   blobdata b;

From aa82f786c730cb27a69bb70d0806ccc384a5890a Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Wed, 11 Feb 2015 15:55:53 -0800
Subject: [PATCH 06/16] Fix log statement

---
 src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index c9741c81d..a11bfdc8c 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -675,7 +675,7 @@ void BlockchainLMDB::open(const std::string& filename)
   lmdb_db_open(txn, LMDB_OUTPUT_GINDICES, MDB_CREATE, m_output_gindices, "Failed to open db handle for m_output_gindices");
 *************************************************/
 
-  lmdb_db_open(txn, LMDB_SPENT_KEYS, MDB_CREATE, m_spent_keys, "Failed to open db handle for m_outputs");
+  lmdb_db_open(txn, LMDB_SPENT_KEYS, MDB_CREATE, m_spent_keys, "Failed to open db handle for m_spent_keys");
 
   mdb_set_dupsort(txn, m_output_amounts, compare_uint64);
   mdb_set_dupsort(txn, m_tx_outputs, compare_uint64);

From 42f8fe5c7f5c3ed7b0d0090a943bffd518c6554d Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Wed, 11 Feb 2015 15:55:53 -0800
Subject: [PATCH 07/16] Fix formatting

---
 src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index a11bfdc8c..9f6bc6b31 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -756,7 +756,6 @@ void BlockchainLMDB::unlock()
   check_open();
 }
 
-
 bool BlockchainLMDB::block_exists(const crypto::hash& h) const
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
@@ -772,7 +771,7 @@ bool BlockchainLMDB::block_exists(const crypto::hash& h) const
   if (get_result == MDB_NOTFOUND)
   {
     txn.commit();
-    LOG_PRINT_L1("Block with hash " << epee::string_tools::pod_to_hex(h) << "not found in db");
+    LOG_PRINT_L1("Block with hash " << epee::string_tools::pod_to_hex(h) << " not found in db");
     return false;
   }
   else if (get_result)
@@ -1075,7 +1074,7 @@ bool BlockchainLMDB::tx_exists(const crypto::hash& h) const
   if (get_result == MDB_NOTFOUND)
   {
     txn.commit();
-    LOG_PRINT_L1("transaction with hash " << epee::string_tools::pod_to_hex(h) << "not found in db");
+    LOG_PRINT_L1("transaction with hash " << epee::string_tools::pod_to_hex(h) << " not found in db");
     return false;
   }
   else if (get_result)
@@ -1097,7 +1096,7 @@ uint64_t BlockchainLMDB::get_tx_unlock_time(const crypto::hash& h) const
   MDB_val result;
   auto get_result = mdb_get(txn, m_tx_unlocks, &key, &result);
   if (get_result == MDB_NOTFOUND)
-    throw1(TX_DNE(std::string("tx unlock time with hash ").append(epee::string_tools::pod_to_hex(h)).append("not found in db").c_str()));
+    throw1(TX_DNE(std::string("tx unlock time with hash ").append(epee::string_tools::pod_to_hex(h)).append(" not found in db").c_str()));
   else if (get_result)
     throw0(DB_ERROR("DB error attempting to fetch tx unlock time from hash"));
 
@@ -1117,7 +1116,7 @@ transaction BlockchainLMDB::get_tx(const crypto::hash& h) const
   MDB_val result;
   auto get_result = mdb_get(txn, m_txs, &key, &result);
   if (get_result == MDB_NOTFOUND)
-    throw1(TX_DNE(std::string("tx with hash ").append(epee::string_tools::pod_to_hex(h)).append("not found in db").c_str()));
+    throw1(TX_DNE(std::string("tx with hash ").append(epee::string_tools::pod_to_hex(h)).append(" not found in db").c_str()));
   else if (get_result)
     throw0(DB_ERROR("DB error attempting to fetch tx from hash"));
 
@@ -1177,7 +1176,7 @@ uint64_t BlockchainLMDB::get_tx_block_height(const crypto::hash& h) const
   auto get_result = mdb_get(txn, m_tx_heights, &key, &result);
   if (get_result == MDB_NOTFOUND)
   {
-    throw1(TX_DNE(std::string("tx height with hash ").append(epee::string_tools::pod_to_hex(h)).append("not found in db").c_str()));
+    throw1(TX_DNE(std::string("tx height with hash ").append(epee::string_tools::pod_to_hex(h)).append(" not found in db").c_str()));
   }
   else if (get_result)
     throw0(DB_ERROR("DB error attempting to fetch tx height from hash"));

From ce71abd0fe9739c3557ba5fce446d1244670976f Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Thu, 19 Feb 2015 06:37:00 -0800
Subject: [PATCH 08/16] Move LMDB storage to subfolder

---
 src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp | 10 ++++++++++
 src/cryptonote_core/blockchain.cpp                |  3 ++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index 9f6bc6b31..f7e8c5dda 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -630,6 +630,16 @@ void BlockchainLMDB::open(const std::string& filename)
       throw0(DB_OPEN_FAILURE(std::string("Failed to create directory ").append(filename).c_str()));
   }
 
+  // check for existing LMDB files in base directory
+  boost::filesystem::path old_files = direc.parent_path();
+  if (boost::filesystem::exists(old_files / "data.mdb") ||
+      boost::filesystem::exists(old_files / "lock.mdb"))
+  {
+    LOG_PRINT_L0("Found existing LMDB files in " << old_files.c_str());
+    LOG_PRINT_L0("Move data.mdb and/or lock.mdb to " << filename << ", or delete them, and then restart");
+    throw DB_ERROR("Database could not be opened");
+  }
+
   m_folder = filename;
 
   // set up lmdb environment
diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index b4b1a4c86..b2d979432 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -237,8 +237,9 @@ bool Blockchain::init(const std::string& config_folder, bool testnet)
   m_testnet = testnet;
 
   boost::filesystem::path folder(m_config_folder);
+  folder /= "lmdb";
 
-  LOG_PRINT_L0("Loading blockchain...");
+  LOG_PRINT_L0("Loading blockchain from folder " << folder.c_str() << " ...");
 
   //FIXME: update filename for BlockchainDB
   const std::string filename = folder.string();

From 3676ac5841b1e433830323b3c51bf78e96947054 Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Wed, 11 Feb 2015 15:55:53 -0800
Subject: [PATCH 09/16] Add profiling to block and tx processing

---
 src/cryptonote_core/blockchain_db.cpp | 38 +++++++++++++++++++++++++++
 src/cryptonote_core/blockchain_db.h   | 10 +++++++
 2 files changed, 48 insertions(+)

diff --git a/src/cryptonote_core/blockchain_db.cpp b/src/cryptonote_core/blockchain_db.cpp
index 0ee10bd4d..615b08814 100644
--- a/src/cryptonote_core/blockchain_db.cpp
+++ b/src/cryptonote_core/blockchain_db.cpp
@@ -28,6 +28,7 @@
 
 #include "cryptonote_core/blockchain_db.h"
 #include "cryptonote_format_utils.h"
+#include "profile_tools.h"
 
 using epee::string_tools::pod_to_hex;
 
@@ -73,18 +74,29 @@ uint64_t BlockchainDB::add_block( const block& blk
                                 , const std::vector<transaction>& txs
                                 )
 {
+  TIME_MEASURE_START(time1);
   crypto::hash blk_hash = get_block_hash(blk);
+  TIME_MEASURE_FINISH(time1);
+  time_blk_hash += time1;
 
   // call out to subclass implementation to add the block & metadata
+  time1 = epee::misc_utils::get_tick_count();
   add_block(blk, block_size, cumulative_difficulty, coins_generated);
+  TIME_MEASURE_FINISH(time1);
+  time_add_block1 += time1;
 
   // call out to add the transactions
 
+  time1 = epee::misc_utils::get_tick_count();
   add_transaction(blk_hash, blk.miner_tx);
   for (const transaction& tx : txs)
   {
     add_transaction(blk_hash, tx);
   }
+  TIME_MEASURE_FINISH(time1);
+  time_add_transaction += time1;
+
+  ++num_calls;
 
   return height();
 }
@@ -119,4 +131,30 @@ void BlockchainDB::remove_transaction(const crypto::hash& tx_hash)
   remove_transaction_data(tx_hash, tx);
 }
 
+void BlockchainDB::reset_stats()
+{
+  num_calls = 0;
+  time_blk_hash = 0;
+  time_add_block1 = 0;
+  time_add_transaction = 0;
+}
+
+void BlockchainDB::show_stats()
+{
+  LOG_PRINT_L1(ENDL
+    << "*********************************"
+    << ENDL
+    << "num_calls: " << num_calls
+    << ENDL
+    << "time_blk_hash: " << time_blk_hash << "ms"
+    << ENDL
+    << "time_add_block1: " << time_add_block1 << "ms"
+    << ENDL
+    << "time_add_transaction: " << time_add_transaction << "ms"
+    << ENDL
+    << "*********************************"
+    << ENDL
+  );
+}
+
 }  // namespace cryptonote
diff --git a/src/cryptonote_core/blockchain_db.h b/src/cryptonote_core/blockchain_db.h
index db56c7c07..531de04bd 100644
--- a/src/cryptonote_core/blockchain_db.h
+++ b/src/cryptonote_core/blockchain_db.h
@@ -301,12 +301,22 @@ private:
   // helper function to remove transaction from blockchain
   void remove_transaction(const crypto::hash& tx_hash);
 
+  uint64_t num_calls = 0;
+  uint64_t time_blk_hash = 0;
+  uint64_t time_add_block1 = 0;
+  uint64_t time_add_transaction = 0;
+
 
 public:
 
   // virtual dtor
   virtual ~BlockchainDB() { };
 
+  // reset profiling stats
+  void reset_stats();
+
+  // show profiling stats
+  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;

From 8909d7d82eaf2b130b7d36fb5db7863170356b15 Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Wed, 11 Feb 2015 15:55:53 -0800
Subject: [PATCH 10/16] Improve block and tx processing efficiency by less
 repeat hashing

  BlockchainLMDB::add_block()
  BlockchainLMDB::add_transaction_data()

  BlockchainDB::add_transaction()
---
 .../BlockchainDB_impl/db_lmdb.cpp             |  7 +++---
 .../BlockchainDB_impl/db_lmdb.h               |  3 ++-
 src/cryptonote_core/blockchain_db.cpp         | 24 +++++++++++++++----
 src/cryptonote_core/blockchain_db.h           |  5 ++--
 4 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index f7e8c5dda..849ec8f6d 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -152,12 +152,13 @@ void BlockchainLMDB::add_block( const block& blk
               , const size_t& block_size
               , const difficulty_type& cumulative_difficulty
               , const uint64_t& coins_generated
+              , const crypto::hash& blk_hash
               )
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
   check_open();
 
-  MDB_val_copy<crypto::hash> val_h(get_block_hash(blk));
+  MDB_val_copy<crypto::hash> val_h(blk_hash);
   MDB_val unused;
   if (mdb_get(*m_write_txn, m_block_heights, &val_h, &unused) == 0)
     throw1(BLOCK_EXISTS("Attempting to add block that's already in the db"));
@@ -243,12 +244,12 @@ void BlockchainLMDB::remove_block()
       throw1(DB_ERROR("Failed to add removal of block hash to db transaction"));
 }
 
-void BlockchainLMDB::add_transaction_data(const crypto::hash& blk_hash, const transaction& tx)
+void BlockchainLMDB::add_transaction_data(const crypto::hash& blk_hash, const transaction& tx, const crypto::hash& tx_hash)
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
   check_open();
 
-  MDB_val_copy<crypto::hash> val_h(get_transaction_hash(tx));
+  MDB_val_copy<crypto::hash> val_h(tx_hash);
   MDB_val unused;
   if (mdb_get(*m_write_txn, m_txs, &val_h, &unused) == 0)
       throw1(TX_EXISTS("Attempting to add transaction that's already in the db"));
diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.h b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.h
index 2513aa48a..29fc52fbd 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.h
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.h
@@ -184,11 +184,12 @@ private:
                 , const size_t& block_size
                 , const difficulty_type& cumulative_difficulty
                 , const uint64_t& coins_generated
+                , const crypto::hash& block_hash
                 );
 
   virtual void remove_block();
 
-  virtual void add_transaction_data(const crypto::hash& blk_hash, const transaction& tx);
+  virtual void add_transaction_data(const crypto::hash& blk_hash, const transaction& tx, const crypto::hash& tx_hash);
 
   virtual void remove_transaction_data(const crypto::hash& tx_hash, const transaction& tx);
 
diff --git a/src/cryptonote_core/blockchain_db.cpp b/src/cryptonote_core/blockchain_db.cpp
index 615b08814..af0c9487f 100644
--- a/src/cryptonote_core/blockchain_db.cpp
+++ b/src/cryptonote_core/blockchain_db.cpp
@@ -42,11 +42,21 @@ void BlockchainDB::pop_block()
   pop_block(blk, txs);
 }
 
-void BlockchainDB::add_transaction(const crypto::hash& blk_hash, const transaction& tx)
+void BlockchainDB::add_transaction(const crypto::hash& blk_hash, const transaction& tx, const crypto::hash* tx_hash_ptr)
 {
-  crypto::hash tx_hash = get_transaction_hash(tx);
+  crypto::hash tx_hash;
+  if (!tx_hash_ptr)
+  {
+    // should only need to compute hash for miner transactions
+    tx_hash = get_transaction_hash(tx);
+    LOG_PRINT_L3("null tx_hash_ptr - needed to compute: " << tx_hash);
+  }
+  else
+  {
+    tx_hash = *tx_hash_ptr;
+  }
 
-  add_transaction_data(blk_hash, tx);
+  add_transaction_data(blk_hash, tx, tx_hash);
 
   // iterate tx.vout using indices instead of C++11 foreach syntax because
   // we need the index
@@ -81,7 +91,7 @@ uint64_t BlockchainDB::add_block( const block& blk
 
   // call out to subclass implementation to add the block & metadata
   time1 = epee::misc_utils::get_tick_count();
-  add_block(blk, block_size, cumulative_difficulty, coins_generated);
+  add_block(blk, block_size, cumulative_difficulty, coins_generated, blk_hash);
   TIME_MEASURE_FINISH(time1);
   time_add_block1 += time1;
 
@@ -89,9 +99,13 @@ uint64_t BlockchainDB::add_block( const block& blk
 
   time1 = epee::misc_utils::get_tick_count();
   add_transaction(blk_hash, blk.miner_tx);
+  int tx_i = 0;
+  crypto::hash tx_hash = null_hash;
   for (const transaction& tx : txs)
   {
-    add_transaction(blk_hash, tx);
+    tx_hash = blk.tx_hashes[tx_i];
+    add_transaction(blk_hash, tx, &tx_hash);
+    ++tx_i;
   }
   TIME_MEASURE_FINISH(time1);
   time_add_transaction += time1;
diff --git a/src/cryptonote_core/blockchain_db.h b/src/cryptonote_core/blockchain_db.h
index 531de04bd..02620c406 100644
--- a/src/cryptonote_core/blockchain_db.h
+++ b/src/cryptonote_core/blockchain_db.h
@@ -265,13 +265,14 @@ private:
                 , const size_t& block_size
                 , const difficulty_type& cumulative_difficulty
                 , const uint64_t& coins_generated
+                , const crypto::hash& blk_hash
                 ) = 0;
 
   // tells the subclass to remove data about the top block
   virtual void remove_block() = 0;
 
   // tells the subclass to store the transaction and its metadata
-  virtual void add_transaction_data(const crypto::hash& blk_hash, const transaction& tx) = 0;
+  virtual void add_transaction_data(const crypto::hash& blk_hash, const transaction& tx, const crypto::hash& tx_hash) = 0;
 
   // tells the subclass to remove data about a transaction
   virtual void remove_transaction_data(const crypto::hash& tx_hash, const transaction& tx) = 0;
@@ -296,7 +297,7 @@ private:
   void pop_block();
 
   // helper function for add_transactions, to add each individual tx
-  void add_transaction(const crypto::hash& blk_hash, const transaction& tx);
+  void add_transaction(const crypto::hash& blk_hash, const transaction& tx, const crypto::hash* tx_hash_ptr = NULL);
 
   // helper function to remove transaction from blockchain
   void remove_transaction(const crypto::hash& tx_hash);

From 58ecc58be13befb8b5d0e6b847987b2fd9635d2c Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Wed, 11 Feb 2015 15:55:53 -0800
Subject: [PATCH 11/16] BlockchainLMDB: Add support for batch transactions

---
 .../BlockchainDB_impl/db_lmdb.cpp             | 294 ++++++++++++++----
 .../BlockchainDB_impl/db_lmdb.h               |  50 ++-
 2 files changed, 289 insertions(+), 55 deletions(-)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index 849ec8f6d..c30a785ed 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -600,15 +600,23 @@ void BlockchainLMDB::check_open() const
 BlockchainLMDB::~BlockchainLMDB()
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+
+  // batch transaction shouldn't be active at this point. If it is, consider it aborted.
+  if (m_batch_active)
+    batch_abort();
 }
 
-BlockchainLMDB::BlockchainLMDB()
+BlockchainLMDB::BlockchainLMDB(bool batch_transactions)
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
   // initialize folder to something "safe" just in case
   // someone accidentally misuses this class...
   m_folder = "thishsouldnotexistbecauseitisgibberish";
   m_open = false;
+
+  m_batch_transactions = batch_transactions;
+  m_write_txn = nullptr;
+  m_batch_active = false;
   m_height = 0;
 }
 
@@ -720,6 +728,13 @@ void BlockchainLMDB::create(const std::string& filename)
 void BlockchainLMDB::close()
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  if (m_batch_active)
+  {
+    LOG_PRINT_L3("close() first calling batch_abort() due to active batch transaction");
+    batch_abort();
+  }
+  this->sync();
+
   // FIXME: not yet thread safe!!!  Use with care.
   mdb_env_close(m_env);
 }
@@ -727,7 +742,13 @@ void BlockchainLMDB::close()
 void BlockchainLMDB::sync()
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
-  // LMDB documentation leads me to believe this is unnecessary
+
+  // Does nothing unless LMDB environment was opened with MDB_NOSYNC or in part
+  // MDB_NOMETASYNC. Force flush to be synchronous.
+  if (auto result = mdb_env_sync(m_env, true))
+  {
+    throw0(DB_ERROR(std::string("Failed to sync database").append(mdb_strerror(result)).c_str()));
+  }
 }
 
 void BlockchainLMDB::reset()
@@ -867,12 +888,17 @@ uint64_t BlockchainLMDB::get_block_timestamp(const uint64_t& height) const
   check_open();
 
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
-
+  txn_safe* txn_ptr = &txn;
+  if (m_batch_active)
+    txn_ptr = m_write_txn;
+  else
+  {
+    if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+  }
   MDB_val_copy<uint64_t> key(height);
   MDB_val result;
-  auto get_result = mdb_get(txn, m_block_timestamps, &key, &result);
+  auto get_result = mdb_get(*txn_ptr, m_block_timestamps, &key, &result);
   if (get_result == MDB_NOTFOUND)
   {
     throw0(DB_ERROR(std::string("Attempt to get timestamp from height ").append(boost::lexical_cast<std::string>(height)).append(" failed -- timestamp not in db").c_str()));
@@ -880,7 +906,8 @@ uint64_t BlockchainLMDB::get_block_timestamp(const uint64_t& height) const
   else if (get_result)
     throw0(DB_ERROR("Error attempting to retrieve a timestamp from the db"));
 
-  txn.commit();
+  if (! m_batch_active)
+    txn.commit();
   return *(const uint64_t*)result.mv_data;
 }
 
@@ -904,12 +931,18 @@ size_t BlockchainLMDB::get_block_size(const uint64_t& height) const
   check_open();
 
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
+  txn_safe* txn_ptr = &txn;
+  if (m_batch_active)
+    txn_ptr = m_write_txn;
+  else
+  {
+    if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+  }
 
   MDB_val_copy<uint64_t> key(height);
   MDB_val result;
-  auto get_result = mdb_get(txn, m_block_sizes, &key, &result);
+  auto get_result = mdb_get(*txn_ptr, m_block_sizes, &key, &result);
   if (get_result == MDB_NOTFOUND)
   {
     throw0(DB_ERROR(std::string("Attempt to get block size from height ").append(boost::lexical_cast<std::string>(height)).append(" failed -- block size not in db").c_str()));
@@ -917,7 +950,8 @@ size_t BlockchainLMDB::get_block_size(const uint64_t& height) const
   else if (get_result)
     throw0(DB_ERROR("Error attempting to retrieve a block size from the db"));
 
-  txn.commit();
+  if (! m_batch_active)
+    txn.commit();
   return *(const size_t*)result.mv_data;
 }
 
@@ -927,12 +961,17 @@ difficulty_type BlockchainLMDB::get_block_cumulative_difficulty(const uint64_t&
   check_open();
 
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
-
+  txn_safe* txn_ptr = &txn;
+  if (m_batch_active)
+    txn_ptr = m_write_txn;
+  else
+  {
+    if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+  }
   MDB_val_copy<uint64_t> key(height);
   MDB_val result;
-  auto get_result = mdb_get(txn, m_block_diffs, &key, &result);
+  auto get_result = mdb_get(*txn_ptr, m_block_diffs, &key, &result);
   if (get_result == MDB_NOTFOUND)
   {
     throw0(DB_ERROR(std::string("Attempt to get cumulative difficulty from height ").append(boost::lexical_cast<std::string>(height)).append(" failed -- difficulty not in db").c_str()));
@@ -940,7 +979,8 @@ difficulty_type BlockchainLMDB::get_block_cumulative_difficulty(const uint64_t&
   else if (get_result)
     throw0(DB_ERROR("Error attempting to retrieve a cumulative difficulty from the db"));
 
-  txn.commit();
+  if (! m_batch_active)
+    txn.commit();
   return *(difficulty_type*)result.mv_data;
 }
 
@@ -967,12 +1007,18 @@ uint64_t BlockchainLMDB::get_block_already_generated_coins(const uint64_t& heigh
   check_open();
 
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
+  txn_safe* txn_ptr = &txn;
+  if (m_batch_active)
+    txn_ptr = m_write_txn;
+  else
+  {
+    if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+  }
 
   MDB_val_copy<uint64_t> key(height);
   MDB_val result;
-  auto get_result = mdb_get(txn, m_block_coins, &key, &result);
+  auto get_result = mdb_get(*txn_ptr, m_block_coins, &key, &result);
   if (get_result == MDB_NOTFOUND)
   {
     throw0(DB_ERROR(std::string("Attempt to get generated coins from height ").append(boost::lexical_cast<std::string>(height)).append(" failed -- block size not in db").c_str()));
@@ -980,7 +1026,8 @@ uint64_t BlockchainLMDB::get_block_already_generated_coins(const uint64_t& heigh
   else if (get_result)
     throw0(DB_ERROR("Error attempting to retrieve a total generated coins from the db"));
 
-  txn.commit();
+  if (! m_batch_active)
+    txn.commit();
   return *(const uint64_t*)result.mv_data;
 }
 
@@ -990,20 +1037,28 @@ crypto::hash BlockchainLMDB::get_block_hash_from_height(const uint64_t& height)
   check_open();
 
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
+  txn_safe* txn_ptr = &txn;
+  if (m_batch_active)
+    txn_ptr = m_write_txn;
+  else
+  {
+    if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+  }
 
   MDB_val_copy<uint64_t> key(height);
   MDB_val result;
-  auto get_result = mdb_get(txn, m_block_hashes, &key, &result);
+  auto get_result = mdb_get(*txn_ptr, m_block_hashes, &key, &result);
   if (get_result == MDB_NOTFOUND)
   {
     throw0(BLOCK_DNE(std::string("Attempt to get hash from height ").append(boost::lexical_cast<std::string>(height)).append(" failed -- hash not in db").c_str()));
   }
   else if (get_result)
-    throw0(DB_ERROR("Error attempting to retrieve a block hash from the db"));
+    throw0(DB_ERROR(std::string("Error attempting to retrieve a block hash from the db: ").
+          append(mdb_strerror(get_result)).c_str()));
 
-  txn.commit();
+  if (! m_batch_active)
+    txn.commit();
   return *(crypto::hash*)result.mv_data;
 }
 
@@ -1075,6 +1130,10 @@ bool BlockchainLMDB::tx_exists(const crypto::hash& h) const
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
   check_open();
 
+  if (m_batch_active)
+  {
+    LOG_PRINT_L0("WARNING: active batch transaction while creating a read-only txn in tx_exists()");
+  }
   txn_safe txn;
   if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
     throw0(DB_ERROR("Failed to create a transaction for the db"));
@@ -1120,12 +1179,18 @@ transaction BlockchainLMDB::get_tx(const crypto::hash& h) const
   check_open();
 
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
+  txn_safe* txn_ptr = &txn;
+  if (m_batch_active)
+    txn_ptr = m_write_txn;
+  else
+  {
+    if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+  }
 
   MDB_val_copy<crypto::hash> key(h);
   MDB_val result;
-  auto get_result = mdb_get(txn, m_txs, &key, &result);
+  auto get_result = mdb_get(*txn_ptr, m_txs, &key, &result);
   if (get_result == MDB_NOTFOUND)
     throw1(TX_DNE(std::string("tx with hash ").append(epee::string_tools::pod_to_hex(h)).append(" not found in db").c_str()));
   else if (get_result)
@@ -1137,6 +1202,8 @@ transaction BlockchainLMDB::get_tx(const crypto::hash& h) const
   transaction tx;
   if (!parse_and_validate_tx_from_blob(bd, tx))
     throw0(DB_ERROR("Failed to parse tx from blob retrieved from the db"));
+  if (! m_batch_active)
+    txn.commit();
 
   return tx;
 }
@@ -1178,13 +1245,27 @@ 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.
+
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
+  txn_safe* txn_ptr = &txn;
+  if (m_batch_active)
+    txn_ptr = m_write_txn;
+  else
+  {
+    if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+  }
 
   MDB_val_copy<crypto::hash> key(h);
   MDB_val result;
-  auto get_result = mdb_get(txn, m_tx_heights, &key, &result);
+  auto get_result = mdb_get(*txn_ptr, m_tx_heights, &key, &result);
   if (get_result == MDB_NOTFOUND)
   {
     throw1(TX_DNE(std::string("tx height with hash ").append(epee::string_tools::pod_to_hex(h)).append(" not found in db").c_str()));
@@ -1192,6 +1273,9 @@ uint64_t BlockchainLMDB::get_tx_block_height(const crypto::hash& h) const
   else if (get_result)
     throw0(DB_ERROR("DB error attempting to fetch tx height from hash"));
 
+  if (! m_batch_active)
+    txn.commit();
+
   return *(const uint64_t*)result.mv_data;
 }
 
@@ -1334,13 +1418,18 @@ tx_out_index BlockchainLMDB::get_output_tx_and_index_from_global(const uint64_t&
   check_open();
 
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
-
+  txn_safe* txn_ptr = &txn;
+  if (m_batch_active)
+    txn_ptr = m_write_txn;
+  else
+  {
+    if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+  }
   MDB_val_copy<uint64_t> k(index);
   MDB_val v;
 
-  auto get_result = mdb_get(txn, m_output_txs, &k, &v);
+  auto get_result = mdb_get(*txn_ptr, m_output_txs, &k, &v);
   if (get_result == MDB_NOTFOUND)
     throw1(OUTPUT_DNE("output with given index not in db"));
   else if (get_result)
@@ -1348,11 +1437,13 @@ tx_out_index BlockchainLMDB::get_output_tx_and_index_from_global(const uint64_t&
 
   crypto::hash tx_hash = *(crypto::hash*)v.mv_data;
 
-  get_result = mdb_get(txn, m_output_indices, &k, &v);
+  get_result = mdb_get(*txn_ptr, m_output_indices, &k, &v);
   if (get_result == MDB_NOTFOUND)
     throw1(OUTPUT_DNE("output with given index not in db"));
   else if (get_result)
     throw0(DB_ERROR("DB error attempting to fetch output tx index"));
+  if (! m_batch_active)
+    txn.commit();
 
   return tx_out_index(tx_hash, *(const uint64_t *)v.mv_data);
 }
@@ -1363,10 +1454,15 @@ tx_out_index BlockchainLMDB::get_output_tx_and_index(const uint64_t& amount, con
   check_open();
 
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
-
-  lmdb_cur cur(txn, m_output_amounts);
+  txn_safe* txn_ptr = &txn;
+  if (m_batch_active)
+    txn_ptr = m_write_txn;
+  else
+  {
+    if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+  }
+  lmdb_cur cur(*txn_ptr, m_output_amounts);
 
   MDB_val_copy<uint64_t> k(amount);
   MDB_val v;
@@ -1395,7 +1491,8 @@ tx_out_index BlockchainLMDB::get_output_tx_and_index(const uint64_t& amount, con
 
   cur.close();
 
-  txn.commit();
+  if (! m_batch_active)
+    txn.commit();
 
   return get_output_tx_and_index_from_global(glob_index);
 }
@@ -1538,6 +1635,85 @@ bool BlockchainLMDB::has_key_image(const crypto::key_image& img) const
   return false;
 }
 
+void BlockchainLMDB::batch_start()
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  if (! m_batch_transactions)
+    throw0(DB_ERROR("batch transactions not enabled"));
+  if (m_batch_active)
+    throw0(DB_ERROR("batch transaction already in progress"));
+  if (m_write_txn)
+    throw0(DB_ERROR("batch transaction attempted, but m_write_txn already in use"));
+  check_open();
+  // NOTE: need to make sure it's destroyed properly when done
+  if (mdb_txn_begin(m_env, NULL, 0, m_write_batch_txn))
+    throw0(DB_ERROR("Failed to create a transaction for the db"));
+  // indicates this transaction is for batch transactions, but not whether it's
+  // active
+  m_write_batch_txn.m_batch_txn = true;
+  m_write_txn = &m_write_batch_txn;
+  m_batch_active = true;
+  LOG_PRINT_L3("batch transaction: begin");
+}
+
+void BlockchainLMDB::batch_commit()
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  if (! m_batch_transactions)
+    throw0(DB_ERROR("batch transactions not enabled"));
+  if (! m_batch_active)
+    throw0(DB_ERROR("batch transaction not in progress"));
+  check_open();
+  LOG_PRINT_L3("batch transaction: committing...");
+  m_write_txn->commit();
+  LOG_PRINT_L3("batch transaction: committed");
+
+  if (mdb_txn_begin(m_env, NULL, 0, m_write_batch_txn))
+    throw0(DB_ERROR("Failed to create a transaction for the db"));
+  if (! m_write_batch_txn.m_batch_txn)
+    throw0(DB_ERROR("m_write_batch_txn not marked as a batch transaction"));
+  m_write_txn = &m_write_batch_txn;
+}
+
+void BlockchainLMDB::batch_stop()
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  if (! m_batch_transactions)
+    throw0(DB_ERROR("batch transactions not enabled"));
+  if (! m_batch_active)
+    throw0(DB_ERROR("batch transaction not in progress"));
+  check_open();
+  LOG_PRINT_L3("batch transaction: committing...");
+  m_write_txn->commit();
+  // for destruction of batch transaction
+  m_write_txn = nullptr;
+  m_batch_active = false;
+  LOG_PRINT_L3("batch transaction: end");
+}
+
+void BlockchainLMDB::batch_abort()
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  if (! m_batch_transactions)
+    throw0(DB_ERROR("batch transactions not enabled"));
+  if (! m_batch_active)
+    throw0(DB_ERROR("batch transaction not in progress"));
+  check_open();
+  // for destruction of batch transaction
+  m_write_txn = nullptr;
+  // explicitly call in case mdb_env_close() (BlockchainLMDB::close()) called before BlockchainLMDB destructor called.
+  m_write_batch_txn.abort();
+  m_batch_active = false;
+  LOG_PRINT_L3("batch transaction: aborted");
+}
+
+void BlockchainLMDB::set_batch_transactions(bool batch_transactions)
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  m_batch_transactions = batch_transactions;
+  LOG_PRINT_L3("batch transactions " << (m_batch_transactions ? "enabled" : "disabled"));
+}
+
 uint64_t BlockchainLMDB::add_block( const block& blk
                                   , const size_t& block_size
                                   , const difficulty_type& cumulative_difficulty
@@ -1547,23 +1723,31 @@ uint64_t BlockchainLMDB::add_block( const block& blk
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
   check_open();
+
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, 0, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
-  m_write_txn = &txn;
+  if (! m_batch_active)
+  {
+    if (mdb_txn_begin(m_env, NULL, 0, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+    m_write_txn = &txn;
+  }
 
   uint64_t num_outputs = m_num_outputs;
   try
   {
     BlockchainDB::add_block(blk, block_size, cumulative_difficulty, coins_generated, txs);
-    m_write_txn = NULL;
+    if (! m_batch_active)
+    {
+      m_write_txn = NULL;
 
-    txn.commit();
+      txn.commit();
+    }
   }
   catch (...)
   {
     m_num_outputs = num_outputs;
-    m_write_txn = NULL;
+    if (! m_batch_active)
+      m_write_txn = NULL;
     throw;
   }
 
@@ -1574,17 +1758,23 @@ void BlockchainLMDB::pop_block(block& blk, std::vector<transaction>& txs)
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, 0, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
-  m_write_txn = &txn;
+  if (! m_batch_active)
+  {
+    if (mdb_txn_begin(m_env, NULL, 0, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+    m_write_txn = &txn;
+  }
 
   uint64_t num_outputs = m_num_outputs;
   try
   {
     BlockchainDB::pop_block(blk, txs);
-    m_write_txn = NULL;
+    if (! m_batch_active)
+    {
+      m_write_txn = NULL;
 
-    txn.commit();
+      txn.commit();
+    }
   }
   catch (...)
   {
diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.h b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.h
index 29fc52fbd..0b4b5ec1a 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.h
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.h
@@ -38,8 +38,23 @@ struct txn_safe
   txn_safe() : m_txn(NULL) { }
   ~txn_safe()
   {
-    if(m_txn != NULL)
+    LOG_PRINT_L3("txn_safe: destructor");
+    if (m_txn != NULL)
     {
+      if (m_batch_txn) // this is a batch txn and should have been handled before this point for safety
+      {
+        LOG_PRINT_L0("WARNING: txn_safe: m_txn is a batch txn and it's not NULL in destructor - calling mdb_txn_abort()");
+      }
+      else
+      {
+        // Example of when this occurs: a lookup fails, so a read-only txn is
+        // aborted through this destructor. However, successful read-only txns
+        // ideally should have been committed when done and not end up here.
+        //
+        // NOTE: not sure if this is ever reached for a non-batch write
+        // transaction, but it's probably not ideal if it did.
+        LOG_PRINT_L3("txn_safe: m_txn not NULL in destructor - calling mdb_txn_abort()");
+      }
       mdb_txn_abort(m_txn);
     }
   }
@@ -60,6 +75,24 @@ struct txn_safe
     m_txn = NULL;
   }
 
+  // This should only be needed for batch transaction which must be ensured to
+  // be aborted before mdb_env_close, not after. So we can't rely on
+  // BlockchainLMDB destructor to call txn_safe destructor, as that's too late
+  // to properly abort, since mdb_env_close would have been called earlier.
+  void abort()
+  {
+    LOG_PRINT_L3("txn_safe: abort()");
+    if(m_txn != NULL)
+    {
+      mdb_txn_abort(m_txn);
+      m_txn = NULL;
+    }
+    else
+    {
+      LOG_PRINT_L0("WARNING: txn_safe: abort() called, but m_txn is NULL");
+    }
+  }
+
   operator MDB_txn*()
   {
     return m_txn;
@@ -71,13 +104,14 @@ struct txn_safe
   }
 
   MDB_txn* m_txn;
+  bool m_batch_txn = false;
 };
 
 
 class BlockchainLMDB : public BlockchainDB
 {
 public:
-  BlockchainLMDB();
+  BlockchainLMDB(bool batch_transactions=false);
   ~BlockchainLMDB();
 
   virtual void open(const std::string& filename);
@@ -177,6 +211,12 @@ public:
                             , const std::vector<transaction>& txs
                             );
 
+  virtual void set_batch_transactions(bool batch_transactions);
+  virtual void batch_start();
+  virtual void batch_commit();
+  virtual void batch_stop();
+  virtual void batch_abort();
+
   virtual void pop_block(block& blk, std::vector<transaction>& txs);
 
 private:
@@ -264,7 +304,11 @@ private:
   uint64_t m_height;
   uint64_t m_num_outputs;
   std::string m_folder;
-  txn_safe* m_write_txn;
+  txn_safe* m_write_txn; // may point to either a short-lived txn or a batch txn
+  txn_safe m_write_batch_txn; // persist batch txn outside of BlockchainLMDB
+
+  bool m_batch_transactions; // support for batch transactions
+  bool m_batch_active; // whether batch transaction is in progress
 };
 
 }  // namespace cryptonote

From b7a2d84919bc28b3747974509f932e64907e357a Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Wed, 18 Feb 2015 20:52:44 -0800
Subject: [PATCH 12/16] BlockchainLMDB: Add check for open database to two
 functions

---
 src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index c30a785ed..c3c0724ce 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -742,6 +742,7 @@ void BlockchainLMDB::close()
 void BlockchainLMDB::sync()
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  check_open();
 
   // Does nothing unless LMDB environment was opened with MDB_NOSYNC or in part
   // MDB_NOMETASYNC. Force flush to be synchronous.
@@ -1757,6 +1758,8 @@ uint64_t BlockchainLMDB::add_block( const block& blk
 void BlockchainLMDB::pop_block(block& blk, std::vector<transaction>& txs)
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  check_open();
+
   txn_safe txn;
   if (! m_batch_active)
   {

From 7a66b8bbcfb3f8084141d8ffb1154a3a514a9ee5 Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Wed, 11 Feb 2015 15:55:53 -0800
Subject: [PATCH 13/16] BlockchainDB: Add virtual function declarations for
 batch transactions

---
 src/cryptonote_core/blockchain_db.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/cryptonote_core/blockchain_db.h b/src/cryptonote_core/blockchain_db.h
index 02620c406..25e9781f8 100644
--- a/src/cryptonote_core/blockchain_db.h
+++ b/src/cryptonote_core/blockchain_db.h
@@ -347,6 +347,9 @@ public:
   // release db lock
   virtual void unlock() = 0;
 
+  virtual void batch_start() = 0;
+  virtual void batch_stop() = 0;
+  virtual void set_batch_transactions(bool) = 0;
 
   // adds a block with the given metadata to the top of the blockchain, returns the new height
   // NOTE: subclass implementations of this (or the functions it calls) need

From 8529c0ea9aa305f097d4a2c89d581163e208e04f Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Wed, 11 Feb 2015 15:55:53 -0800
Subject: [PATCH 14/16] BlockchainDB, BlockchainLMDB: Add profiling for DB
 commits

---
 src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp | 10 ++++++++++
 src/cryptonote_core/blockchain_db.cpp             |  3 +++
 src/cryptonote_core/blockchain_db.h               |  5 +++++
 3 files changed, 18 insertions(+)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index c3c0724ce..25c25f399 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -33,6 +33,7 @@
 
 #include "cryptonote_core/cryptonote_format_utils.h"
 #include "crypto/crypto.h"
+#include "profile_tools.h"
 
 using epee::string_tools::pod_to_hex;
 
@@ -1666,7 +1667,10 @@ void BlockchainLMDB::batch_commit()
     throw0(DB_ERROR("batch transaction not in progress"));
   check_open();
   LOG_PRINT_L3("batch transaction: committing...");
+  TIME_MEASURE_START(time1);
   m_write_txn->commit();
+  TIME_MEASURE_FINISH(time1);
+  time_commit1 += time1;
   LOG_PRINT_L3("batch transaction: committed");
 
   if (mdb_txn_begin(m_env, NULL, 0, m_write_batch_txn))
@@ -1685,7 +1689,10 @@ void BlockchainLMDB::batch_stop()
     throw0(DB_ERROR("batch transaction not in progress"));
   check_open();
   LOG_PRINT_L3("batch transaction: committing...");
+  TIME_MEASURE_START(time1);
   m_write_txn->commit();
+  TIME_MEASURE_FINISH(time1);
+  time_commit1 += time1;
   // for destruction of batch transaction
   m_write_txn = nullptr;
   m_batch_active = false;
@@ -1741,7 +1748,10 @@ uint64_t BlockchainLMDB::add_block( const block& blk
     {
       m_write_txn = NULL;
 
+      TIME_MEASURE_START(time1);
       txn.commit();
+      TIME_MEASURE_FINISH(time1);
+      time_commit1 += time1;
     }
   }
   catch (...)
diff --git a/src/cryptonote_core/blockchain_db.cpp b/src/cryptonote_core/blockchain_db.cpp
index af0c9487f..74de19585 100644
--- a/src/cryptonote_core/blockchain_db.cpp
+++ b/src/cryptonote_core/blockchain_db.cpp
@@ -151,6 +151,7 @@ void BlockchainDB::reset_stats()
   time_blk_hash = 0;
   time_add_block1 = 0;
   time_add_transaction = 0;
+  time_commit1 = 0;
 }
 
 void BlockchainDB::show_stats()
@@ -166,6 +167,8 @@ void BlockchainDB::show_stats()
     << ENDL
     << "time_add_transaction: " << time_add_transaction << "ms"
     << ENDL
+    << "time_commit1: " << time_commit1 << "ms"
+    << ENDL
     << "*********************************"
     << ENDL
   );
diff --git a/src/cryptonote_core/blockchain_db.h b/src/cryptonote_core/blockchain_db.h
index 25e9781f8..ba0e5738b 100644
--- a/src/cryptonote_core/blockchain_db.h
+++ b/src/cryptonote_core/blockchain_db.h
@@ -308,6 +308,11 @@ private:
   uint64_t time_add_transaction = 0;
 
 
+protected:
+
+  uint64_t time_commit1 = 0;
+
+
 public:
 
   // virtual dtor

From 83fb6d8d07c0b473e7b53a35d8e69f586bd1945e Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Tue, 10 Feb 2015 20:01:02 -0800
Subject: [PATCH 15/16] BlockchainLMDB: Add batch transaction support to
 tx_exists()

---
 .../BlockchainDB_impl/db_lmdb.cpp             | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index 25c25f399..4e9f6cb28 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -1132,20 +1132,23 @@ bool BlockchainLMDB::tx_exists(const crypto::hash& h) const
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
   check_open();
 
-  if (m_batch_active)
-  {
-    LOG_PRINT_L0("WARNING: active batch transaction while creating a read-only txn in tx_exists()");
-  }
   txn_safe txn;
-  if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
-    throw0(DB_ERROR("Failed to create a transaction for the db"));
+  txn_safe* txn_ptr = &txn;
+  if (m_batch_active)
+    txn_ptr = m_write_txn;
+  else
+  {
+    if (mdb_txn_begin(m_env, NULL, MDB_RDONLY, txn))
+      throw0(DB_ERROR("Failed to create a transaction for the db"));
+  }
 
   MDB_val_copy<crypto::hash> key(h);
   MDB_val result;
-  auto get_result = mdb_get(txn, m_txs, &key, &result);
+  auto get_result = mdb_get(*txn_ptr, m_txs, &key, &result);
   if (get_result == MDB_NOTFOUND)
   {
-    txn.commit();
+    if (! m_batch_active)
+      txn.commit();
     LOG_PRINT_L1("transaction with hash " << epee::string_tools::pod_to_hex(h) << " not found in db");
     return false;
   }

From 6485dacc2fcaab7eb6db63c46716ffdfa0c568c4 Mon Sep 17 00:00:00 2001
From: warptangent <warptangent@inbox.com>
Date: Tue, 10 Feb 2015 20:01:02 -0800
Subject: [PATCH 16/16] BlockchainLMDB: Add profiling to tx_exists()

---
 src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp | 5 ++++-
 src/cryptonote_core/blockchain_db.cpp             | 3 +++
 src/cryptonote_core/blockchain_db.h               | 1 +
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
index 4e9f6cb28..a09d9331c 100644
--- a/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
+++ b/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp
@@ -1126,7 +1126,6 @@ uint64_t BlockchainLMDB::height() const
   return m_height;
 }
 
-
 bool BlockchainLMDB::tx_exists(const crypto::hash& h) const
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
@@ -1144,7 +1143,11 @@ bool BlockchainLMDB::tx_exists(const crypto::hash& h) const
 
   MDB_val_copy<crypto::hash> key(h);
   MDB_val result;
+
+  TIME_MEASURE_START(time1);
   auto get_result = mdb_get(*txn_ptr, m_txs, &key, &result);
+  TIME_MEASURE_FINISH(time1);
+  time_tx_exists += time1;
   if (get_result == MDB_NOTFOUND)
   {
     if (! m_batch_active)
diff --git a/src/cryptonote_core/blockchain_db.cpp b/src/cryptonote_core/blockchain_db.cpp
index 74de19585..fc8aeef4e 100644
--- a/src/cryptonote_core/blockchain_db.cpp
+++ b/src/cryptonote_core/blockchain_db.cpp
@@ -149,6 +149,7 @@ void BlockchainDB::reset_stats()
 {
   num_calls = 0;
   time_blk_hash = 0;
+  time_tx_exists = 0;
   time_add_block1 = 0;
   time_add_transaction = 0;
   time_commit1 = 0;
@@ -163,6 +164,8 @@ void BlockchainDB::show_stats()
     << ENDL
     << "time_blk_hash: " << time_blk_hash << "ms"
     << ENDL
+    << "time_tx_exists: " << time_tx_exists << "ms"
+    << ENDL
     << "time_add_block1: " << time_add_block1 << "ms"
     << ENDL
     << "time_add_transaction: " << time_add_transaction << "ms"
diff --git a/src/cryptonote_core/blockchain_db.h b/src/cryptonote_core/blockchain_db.h
index ba0e5738b..2a7fa8f82 100644
--- a/src/cryptonote_core/blockchain_db.h
+++ b/src/cryptonote_core/blockchain_db.h
@@ -310,6 +310,7 @@ private:
 
 protected:
 
+  mutable uint64_t time_tx_exists = 0;
   uint64_t time_commit1 = 0;