BlockchainDB/LMDB/BDB: Extract DB txn functions for block add/remove

src/blockchain_db/berkeleydb/db_bdb.cpp

@@ -1831,6 +1831,21 @@ void BlockchainBDB::set_batch_transactions(bool batch_transactions)
     LOG_PRINT_L3("batch transactions " << (m_batch_transactions ? "enabled" : "disabled"));
 }
 
+void BlockchainBDB::block_txn_start()
+{
+  // TODO
+}
+
+void BlockchainBDB::block_txn_stop()
+{
+  // TODO
+}
+
+void BlockchainBDB::block_txn_abort()
+{
+  // TODO
+}
+
 uint64_t BlockchainBDB::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)
 {
     LOG_PRINT_L3("BlockchainBDB::" << __func__);

src/blockchain_db/berkeleydb/db_bdb.h

@@ -328,6 +328,10 @@ public:
   virtual void batch_stop();
   virtual void batch_abort();
 
+  virtual void block_txn_start();
+  virtual void block_txn_stop();
+  virtual void block_txn_abort();
+
   virtual void pop_block(block& blk, std::vector<transaction>& txs);
 
 #if defined(BDB_BULK_CAN_THREAD)

src/blockchain_db/blockchain_db.h

@@ -368,6 +368,10 @@ public:
   virtual void batch_stop() = 0;
   virtual void set_batch_transactions(bool) = 0;
 
+  virtual void block_txn_start() = 0;
+  virtual void block_txn_stop() = 0;
+  virtual void block_txn_abort() = 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
   // to handle undoing any partially-added blocks in the event of a failure.

src/blockchain_db/lmdb/db_lmdb.cpp

@@ -2190,6 +2190,44 @@ void BlockchainLMDB::set_batch_transactions(bool batch_transactions)
   LOG_PRINT_L3("batch transactions " << (m_batch_transactions ? "enabled" : "disabled"));
 }
 
+void BlockchainLMDB::block_txn_start()
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  if (! m_batch_active && m_write_txn)
+    throw0(DB_ERROR((std::string("Attempted to start new write txn when write txn already exists in ")+__FUNCTION__).c_str()));
+  if (! m_batch_active)
+  {
+    m_write_txn = new mdb_txn_safe();
+    if (auto mdb_res = mdb_txn_begin(m_env, NULL, 0, *m_write_txn))
+      throw0(DB_ERROR(lmdb_error("Failed to create a transaction for the db: ", mdb_res).c_str()));
+  }
+}
+
+void BlockchainLMDB::block_txn_stop()
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  if (! m_batch_active)
+  {
+    TIME_MEASURE_START(time1);
+    m_write_txn->commit();
+    TIME_MEASURE_FINISH(time1);
+    time_commit1 += time1;
+
+    delete m_write_txn;
+    m_write_txn = NULL;
+  }
+}
+
+void BlockchainLMDB::block_txn_abort()
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  if (! m_batch_active)
+  {
+    delete m_write_txn;
+    m_write_txn = NULL;
+  }
+}
+
 uint64_t BlockchainLMDB::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)
 {

src/blockchain_db/lmdb/db_lmdb.h

@@ -194,6 +194,10 @@ public:
   virtual void batch_stop();
   virtual void batch_abort();
 
+  virtual void block_txn_start();
+  virtual void block_txn_stop();
+  virtual void block_txn_abort();
+
   virtual void pop_block(block& blk, std::vector<transaction>& txs);
 
   virtual bool can_thread_bulk_indices() const { return true; }