No need for lock

sqlitecluster/SQLite.cpp

@@ -405,7 +405,8 @@ bool SQLite::beginTransaction(TRANSACTION_TYPE type) {
     uint64_t before = STimeNow();
     _insideTransaction = !SQuery(_db, "starting db transaction", "BEGIN CONCURRENT");
 
-    _sharedData.incrementOpenTransactions();
+    // We actively track transaction counts incrementing and decrementing to log the number of active open transactions at any given moment.
+    _sharedData.openTransactionCount++;
 
     // Because some other thread could commit once we've run `BEGIN CONCURRENT`, this value can be slightly behind
     // where we're actually able to start such that we know we shouldn't get a conflict if this commits successfully on
@@ -790,7 +791,7 @@ int SQLite::commit(const string& description, function<void()>* preCheckpointCal
         _mutexLocked = false;
         _queryCache.clear();
 
-        _sharedData.decrementOpenTransactions();
+        _sharedData.openTransactionCount--;
 
         if (preCheckpointCallback != nullptr) {
             (*preCheckpointCallback)();
@@ -847,7 +848,7 @@ void SQLite::rollback() {
             _rollbackElapsed += STimeNow() - before;
         }
 
-        _sharedData.decrementOpenTransactions();
+        _sharedData.openTransactionCount--;
 
         // Finally done with this.
         _insideTransaction = false;
@@ -1208,16 +1209,6 @@ void SQLite::SharedData::commitTransactionInfo(uint64_t commitID) {
     _committedTransactions.insert(_preparedTransactions.extract(commitID));
 }
 
-void SQLite::SharedData::incrementOpenTransactions() {
-    lock_guard<decltype(_internalStateMutex)> lock(_internalStateMutex);
-    openTransactionCount++;
-}
-
-void SQLite::SharedData::decrementOpenTransactions() {
-    lock_guard<decltype(_internalStateMutex)> lock(_internalStateMutex);
-    openTransactionCount--;
-}
-
 map<uint64_t, tuple<string, string, uint64_t>> SQLite::SharedData::popCommittedTransactions() {
     lock_guard<decltype(_internalStateMutex)> lock(_internalStateMutex);
     decltype(_committedTransactions) result;

sqlitecluster/SQLite.h

@@ -314,9 +314,7 @@ class SQLite {
         // If set to false, this prevents any thread from being able to commit to the DB.
         atomic<bool> _commitEnabled;
 
-        // These blocks are to monitor the number of open transactions on the whole server.
-        void incrementOpenTransactions();
-        void decrementOpenTransactions();
+        // This variable is used to monitor the number of open transactions on the whole server.
         atomic<int64_t> openTransactionCount;
 
         SPerformanceTimer _commitLockTimer;