From: Kevin Lewis
Date: December 16 2008 11:12pm
Subject: Please review Bug#41194 - Falcon durability should occur earlier in
 the commit process
List-Archive: http://lists.mysql.com/falcon/316
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Vlad, Ann, Kelly and Jim,

Please take a look at this change to move the point of durability up 
higher in the commit process.  I also needed to make the gopher thread 
wait for the transaction.  Many bad things would happen when a 
transaction is completed before it is fully committed.

Kevin



Bug#41194 Falcon durability should occur earlier in the commit process.

   http://lists.mysql.com/commits/61832

2938 Kevin Lewis	2008-12-16
       Bug#41194 - Move point of durability up higher in the commit
       so that by the time other waiting threads are signaled that
       this transaction is committed, it will already be durable.

modified:
   storage/falcon/Transaction.cpp

per-file messages:
   storage/falcon/Transaction.cpp
     Bug#41194 - Move point of durability up higher in the commit
     so that by the time other waiting threads are signalled that
     this transaction is committed, it will already be durable.
=== modified file 'storage/falcon/Transaction.cpp'
--- a/storage/falcon/Transaction.cpp	2008-12-16 20:40:38 +0000
+++ b/storage/falcon/Transaction.cpp	2008-12-16 22:48:55 +0000
@@ -266,6 +266,11 @@ void Transaction::commit()

  	database->flushInversion(this);

+	// Write the commit message to the serial log for durability.
+	// If a crash happens after this, the recover will commit.
+
+	database->commit(this);
+
  	// Transfer transaction from active list to committed list, set 
committed state

  	Sync 
syncActiveTransactions(&transactionManager->activeTransactions.syncObject,
"Transaction::commit(2)");
@@ -294,8 +299,6 @@ void Transaction::commit()
  	
  	syncIsActive.unlock(); // signal waiting transactions

-	database->commit(this);
-
  	delete [] xid;
  	xid = NULL;
  	xidLength = 0;
@@ -1413,12 +1416,30 @@ void Transaction::getInfo(InfoTable* inf
  		}
  }

+// Called by the gopher thread to complete this transaction
+
  void Transaction::fullyCommitted(void)
  {
  	ASSERT(inList);

  	if (useCount < 2)
-		Log::debug("Transaction::fullyCommitted: funny use count\n");
+		Log::debug("Transaction::fullyCommitted: Unusual use count=%d\n", 
useCount);
+
+	// The commit record is flushed to the serial log before the transaction
+	// is fully committed and waiting threads are signalled.  This gopher may
+	// have picked up that record too soon, so wait for that transaction.
+
+	while (isActive())
+		{
+		try
+			{
+			Sync sync(&syncIsActive, "Transaction::fullyCommitted");
+			sync.lock(Shared, 1000);
+			}
+		catch  (...)
+			{
+			}
+		}

  	writeComplete();
  	releaseCommittedTransaction();