bzr commit into mysql-6.0-falcon-ann branch (olav:2742) WL#4654

[Olav Sandstaa]

#At file:///home/os136802/mysql/develop/repo/falcon-newdeps4-commitnoupdates/ based on revid:olav@stripped

 2742 Olav Sandstaa	2008-12-08
      WL#4654 New transaction dependency manager for Falcon
      
      Patch 1 for optimization of read-only transactions: re-enable the call to
      Transaction::commitNoUpdates(). The transaction object is deleted at the
      end of Transaction::commitNoUpdates() and that no re-use of transaction objects
      is implemented yet.
modified:
  storage/falcon/Transaction.cpp

per-file messages:
  storage/falcon/Transaction.cpp
    Re-enable call to commitNoUpdates(). Added code for deleting the transaction object since
    no re-use is implemented yet.
=== modified file 'storage/falcon/Transaction.cpp'

=== modified file 'storage/falcon/Transaction.cpp'
--- a/storage/falcon/Transaction.cpp	2008-12-08 11:28:35 +0000
+++ b/storage/falcon/Transaction.cpp	2008-12-08 12:22:08 +0000
@@ -209,15 +209,11 @@
 
 	releaseSavepoints();
 
-	// NOTE: temporary disabled the optimization for read only transactions.
-	// This will be included in a follow up patch
-
-	//if (!hasUpdates)
-	//	{
-	//	commitNoUpdates();
-	//	
-	//	return;
-	//	}
+	if (!hasUpdates)
+		{
+		commitNoUpdates();
+		return;
+		}
 
 	TransactionManager *transactionManager = database->transactionManager;
 	addRef();
@@ -246,13 +242,7 @@
 	if (hasLocks)
 		releaseRecordLocks();
 
-	// NOTE: The if test can be removed when the handling of read-only
-	// transactions has been re-implemented
-
-	if (hasUpdates)
-		database->serialLog->preCommit(this);
-	else 
-		writePending = false;
+	database->serialLog->preCommit(this);
 
 	Sync syncRec(&syncRecords,"Transaction::commit(1.5)");
 	syncRec.lock(Shared);
@@ -322,9 +312,6 @@
 
 void Transaction::commitNoUpdates(void)
 {
-	// NOTE: This method is not in use by the new dependency manager.
-	// It will be re-enabled in a follow-up patch
-
 	TransactionManager *transactionManager = database->transactionManager;
 	addRef();
 	ASSERT(!deferredIndexes);
@@ -337,8 +324,11 @@
 	if (hasLocks)
 		releaseRecordLocks();
 
+	// NOTE: Temporarily upgraded from using Shared to Exclusive locking.
+	// See explanation further down
+
 	Sync syncActiveTransactions(&transactionManager->activeTransactions.syncObject, "Transaction::commitNoUpdates(2)");
-	syncActiveTransactions.lock(Shared);
+	syncActiveTransactions.lock(Exclusive);
 
 	if (xid)
 		{
@@ -356,6 +346,17 @@
 	transactionId = 0;
 	writePending = false;
 	state = Available;
+
+	// NOTE: This code is hopefully temporar until we have implemented
+	// support for reusing transaction objects:
+	// Remove this transaction from the active list
+
+	inList = false;
+	transactionManager->activeTransactions.remove(this);
+	ASSERT(useCount >= 2);
+	release();
+	sync.unlock();
+
 	syncActiveTransactions.unlock();
 	syncIsActive.unlock();
 	release();