Core/DBLayer:

- Rewrite KeepAlive method for DatabaseWorkerPool. Use mysql_ping instead of explicit select queries, and also schedule KeepAlives for asynchronous threads.
NOTE: While the function is implemented and previous keepalive calls were transformed, it´s possible the keepalive call will need to be placed in several other locations in the code. Please leave feedback on whether or not this fixes your timeout issues.

Update issue #4062

--HG--
branch : trunk

src/server/authserver/Main.cpp

@@ -314,7 +314,7 @@ extern int main(int argc, char **argv)
         {
             loopCounter = 0;
             sLog.outDetail("Ping MySQL to keep connection alive");
-            LoginDatabase.Query("SELECT 1 FROM realmlist");
+            LoginDatabase.KeepAlive();
         }
 #ifdef _WIN32
         if (m_ServiceStatus == 0) stopEvent = true;

src/server/shared/Database/DatabaseWorkerPool.h

@@ -43,6 +43,16 @@ enum MySQLThreadBundle
     MYSQL_BUNDLE_ALL    = MYSQL_BUNDLE_RA | MYSQL_BUNDLE_RAR | MYSQL_BUNDLE_WORLD,
 };
 
+class PingOperation : public SQLOperation
+{
+    /// Operation for idle delaythreads
+    bool Execute()
+    {
+        m_conn->Ping();
+        return true;
+    }
+};
+
 template <class T>
 class DatabaseWorkerPool
 {
@@ -304,6 +314,27 @@ class DatabaseWorkerPool
             return PreparedQueryResult(ret);
         }
 
+        void KeepAlive()
+        {
+            ConnectionMap::const_iterator itr;
+            {
+                /*! MapUpdate + unbundled threads */
+                ACE_Guard<ACE_Thread_Mutex> guard(m_connectionMap_mtx);
+                itr = m_sync_connections.find(ACE_Based::Thread::current());
+                if (itr != m_sync_connections.end())
+                    itr->second->Ping();
+            }
+
+            if (m_bundle_conn)
+                m_bundle_conn->Ping();
+
+            /// Assuming all worker threads are free, every worker thread will receive 1 ping operation request
+            /// If one or more worker threads are busy, the ping operations will not be split evenly, but this doesn't matter 
+            /// as the sole purpose is to prevent connections from idling.
+            for (size_t i = 0; i < m_async_connections.size(); ++i)
+                Enqueue(new PingOperation);
+        }        
+
     private:
         unsigned long escape_string(char *to, const char *from, unsigned long length)
         {

src/server/shared/Database/MySQLConnection.h

@@ -50,6 +50,7 @@ class MySQLConnection
         void CommitTransaction();
 
         operator bool () const { return m_Mysql != NULL; }
+        void Ping() { mysql_ping(m_Mysql); }
 
     protected:
         MYSQL* GetHandle()  { return m_Mysql; }

src/server/worldserver/Master.cpp

@@ -135,7 +135,7 @@ public:
         {
             loopCounter = 0;
             sLog.outDetail ("Ping MySQL to keep connection alive");
-            LoginDatabase.Query ("SELECT 1 FROM realmlist LIMIT 1");
+            LoginDatabase.KeepAlive();
         }
     }