This should fix bug CORE-5419 : Index garbage collection on varchar c…

…olumn causes server to hang
FirebirdSQL · Jan 27, 2017 · 2d26794 · 2d26794
1 parent 9c32751
commit 2d26794
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Showing 2 changed files with 20 additions and 3 deletions.
diff --git a/src/jrd/Database.h b/src/jrd/Database.h
@@ -150,7 +150,7 @@ class Database : public pool_alloc<type_dbb>, public Firebird::PublicHandle
 	class Sync : public Firebird::RefCounted
 	{
 	public:
-		Sync() : threadId(0), isAst(false)
+		Sync() : threadId(0), isAst(false), lockCounter(0)
 #ifdef DEV_BUILD
 			, lockCount(0)
 #endif
@@ -164,6 +164,7 @@ class Database : public pool_alloc<type_dbb>, public Firebird::PublicHandle
 			--waiters;
 			threadId = getThreadId();
 			isAst = ast;
+			lockCounter++;
 #ifdef DEV_BUILD
 			++lockCount;
 #endif
@@ -186,6 +187,11 @@ class Database : public pool_alloc<type_dbb>, public Firebird::PublicHandle
 			return (waiters.value() > 0);
 		}
 
+		FB_UINT64 getLockCounter() const
+		{
+			return lockCounter;
+		}
+
 #ifdef DEV_BUILD
 		bool locked() const
 		{
@@ -222,6 +228,7 @@ class Database : public pool_alloc<type_dbb>, public Firebird::PublicHandle
 		Firebird::AtomicCounter waiters;
 		FB_THREAD_ID threadId;
 		bool isAst;
+		volatile FB_UINT64 lockCounter;
 #ifdef DEV_BUILD
 		int lockCount;
 #endif

diff --git a/src/jrd/jrd.cpp b/src/jrd/jrd.cpp
@@ -4402,8 +4402,18 @@ bool JRD_reschedule(thread_db* tdbb, SLONG quantum, bool punt)
 
 	if (dbb->dbb_sync->hasContention())
 	{
-		Database::Checkout dcoHolder(dbb);
-		THREAD_YIELD();
+		const FB_UINT64 counter = dbb->dbb_sync->getLockCounter();
+		{
+			Database::Checkout dcoHolder(dbb);
+			THREAD_YIELD();
+
+			// if nobody was able to lock dbb_sync, sleep a bit longer
+			while (dbb->dbb_sync->hasContention() &&
+				   counter == dbb->dbb_sync->getLockCounter())
+			{
+				THREAD_SLEEP(1);
+			}
+		}
 	}
 
 	try {