From 05a292633cdfdb9383d0a914d5b95c838837e1eb Mon Sep 17 00:00:00 2001
From: Machiavelli <none@none>
Date: Sun, 31 Oct 2010 10:55:29 +0100
Subject: [PATCH] =?UTF-8?q?Core/DBLayer:=20-=20Fix=20a=20race=20condition?=
 =?UTF-8?q?=20in=20KeepAlive()=20when=20connections=20are=20using=20mysql?=
 =?UTF-8?q?=20context=20when=20ping=20is=20called.=20-=20Don=C2=B4t=20wait?=
 =?UTF-8?q?=20for=20locks=20to=20be=20released=20on=20a=20connection=20whe?=
 =?UTF-8?q?n=20pinging,=20this=20means=20the=20connection=20is=20not=20idl?=
 =?UTF-8?q?e=20and=20locking=20is=20redundant.?=
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Patch by admin@****.net

Fixes issue #4599

--HG--
branch : trunk
---
 .../shared/Database/DatabaseWorkerPool.h      | 26 ++++++++++++-------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/server/shared/Database/DatabaseWorkerPool.h b/src/server/shared/Database/DatabaseWorkerPool.h
index 899c0f8f63d..9f7bf6d72dc 100755
--- a/src/server/shared/Database/DatabaseWorkerPool.h
+++ b/src/server/shared/Database/DatabaseWorkerPool.h
@@ -37,13 +37,12 @@ class PingOperation : public SQLOperation
     /// Operation for idle delaythreads
     bool Execute()
     {
-        for (;;)
-            if (m_conn->LockIfReady())
-            {
-                m_conn->Ping();
-                m_conn->Unlock();
-                return true;
-            }
+        if (m_conn->LockIfReady())
+        {
+            m_conn->Ping();
+            m_conn->Unlock();
+            return true;
+        }
 
         return false;
     }
@@ -305,10 +304,17 @@ class DatabaseWorkerPool
 
         void KeepAlive()
         {
-            /// Ping syncrhonous connections
+            /// Ping synchronous connections
             for (uint8 i = 0; i < m_connections[IDX_SYNCH].size(); ++i)
-                m_connections[IDX_SYNCH][i]->Ping();
-
+            {
+                T* t = m_connections[IDX_SYNCH][i];
+                if (t->LockIfReady())
+                {
+                    t->Ping();
+                    t->Unlock();
+                }
+            }
+ 
             /// 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.