diff options
Diffstat (limited to 'src/backend/access/transam/xlog.c')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 28fb4c733a6..32ade5d7590 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.158 2004/08/09 16:26:01 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.159 2004/08/11 04:07:15 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -4699,6 +4699,15 @@ CreateCheckPoint(bool shutdown, bool force) checkPoint.ThisTimeLineID = ThisTimeLineID; checkPoint.time = time(NULL); + /* + * We must hold CheckpointStartLock while determining the checkpoint + * REDO pointer. This ensures that any concurrent transaction commits + * will be either not yet logged, or logged and recorded in pg_clog. + * See notes in RecordTransactionCommit(). + */ + LWLockAcquire(CheckpointStartLock, LW_EXCLUSIVE); + + /* And we need WALInsertLock too */ LWLockAcquire(WALInsertLock, LW_EXCLUSIVE); /* @@ -4731,6 +4740,7 @@ CreateCheckPoint(bool shutdown, bool force) ControlFile->checkPointCopy.redo.xrecoff) { LWLockRelease(WALInsertLock); + LWLockRelease(CheckpointStartLock); LWLockRelease(CheckpointLock); END_CRIT_SECTION(); return; @@ -4789,6 +4799,9 @@ CreateCheckPoint(bool shutdown, bool force) * GetSnapshotData needs to get XidGenLock while holding SInvalLock, * so there's a risk of deadlock. Need to find a better solution. See * pgsql-hackers discussion of 17-Dec-01. + * + * XXX actually, the whole UNDO code is dead code and unlikely to ever + * be revived, so the lack of a good solution here is not troubling. */ #ifdef NOT_USED checkPoint.undo = GetUndoRecPtr(); @@ -4798,11 +4811,13 @@ CreateCheckPoint(bool shutdown, bool force) #endif /* - * Now we can release insert lock, allowing other xacts to proceed - * even while we are flushing disk buffers. + * Now we can release insert lock and checkpoint start lock, allowing + * other xacts to proceed even while we are flushing disk buffers. */ LWLockRelease(WALInsertLock); + LWLockRelease(CheckpointStartLock); + /* * Get the other info we need for the checkpoint record. */ |