Core/DBLayer:

- Implement DatabaseWorkerPool::DirectCommitTransaction for synchronous transaction execution (as opposed to asynchronous/enqueued).
- Add MySQL errno 1213 "Deadlock found when trying to get lock; try restarting transaction" handler. If 1213 is called the core will retry to directly execute the transaction a maximum of 5 times.

1 files changed, 9 insertions, 38 deletions

diff --git a/src/server/shared/Database/Transaction.cpp b/src/server/shared/Database/Transaction.cpp
index b09415c6c7c..8604dfc609c 100755
--- a/src/server/shared/Database/Transaction.cpp
+++ b/src/server/shared/Database/Transaction.cpp
@@ -67,45 +67,16 @@ void Transaction::Cleanup()
 
 bool TransactionTask::Execute()
 {
-    std::queue<SQLElementData> &queries = m_trans->m_queries;
-    if (queries.empty())
-        return false;
+    if (m_conn->ExecuteTransaction(m_trans))
+        return true;
 
-    m_conn->BeginTransaction();
-    while (!queries.empty())
+    if (m_conn->GetLastError() == 1213)
     {
-        SQLElementData data = queries.front();
-        switch (data.type)
-        {
-            case SQL_ELEMENT_PREPARED:
-            {
-                PreparedStatement* stmt = data.element.stmt;
-                ASSERT(stmt);
-                if (!m_conn->Execute(stmt))
-                {
-                    sLog->outSQLDriver("[Warning] Transaction aborted. %u queries not executed.", (uint32)queries.size());
-                    m_conn->RollbackTransaction();
-                    return false;
-                }
-                delete data.element.stmt;
-            }
-            break;
-            case SQL_ELEMENT_RAW:
-            {
-                const char* sql = data.element.query;
-                ASSERT(sql);
-                if (!m_conn->Execute(sql))
-                {
-                    sLog->outSQLDriver("[Warning] Transaction aborted. %u queries not executed.", (uint32)queries.size());
-                    m_conn->RollbackTransaction();
-                    return false;
-                }
-                free((void*)const_cast<char*>(sql));
-            }
-            break;
-        }
-        queries.pop();
+        uint8 loopBreaker = 5;  // Handle MySQL Errno 1213 without extending deadlock to the core itself
+        for (uint8 i = 0; i < loopBreaker; ++i)
+            if (m_conn->ExecuteTransaction(m_trans))
+                return true;
     }
-    m_conn->CommitTransaction();
-    return true;
+
+    return false;
 }