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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2004-08-11 04:08:02 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2004-08-11 04:08:02 +0000 |
| commit | d508e0ddd23a35b9cb30ec1a769de40e98d5561f (patch) | |
| tree | 1880529858bde1f01601074dd3767dc6879cb562 /src/backend/access/transam/xlog.c | |
| parent | a1dd58e50990b5a1740371b16a1bd1ccb0721b3e (diff) | |
| download | postgresql-d508e0ddd23a35b9cb30ec1a769de40e98d5561f.tar.gz postgresql-d508e0ddd23a35b9cb30ec1a769de40e98d5561f.zip | |
Fix failure to guarantee that a checkpoint will write out pg_clog updates
for transaction commits that occurred just before the checkpoint. This is
an EXTREMELY serious bug --- kudos to Satoshi Okada for creating a
reproducible test case to prove its existence.
Diffstat (limited to 'src/backend/access/transam/xlog.c')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 8eb154f7bab..a8acf758a8c 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 * - * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.125.2.1 2004/02/23 23:03:43 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.125.2.2 2004/08/11 04:08:00 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -3159,6 +3159,15 @@ CreateCheckPoint(bool shutdown, bool force) checkPoint.ThisStartUpID = ThisStartUpID; 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); /* @@ -3191,6 +3200,7 @@ CreateCheckPoint(bool shutdown, bool force) ControlFile->checkPointCopy.redo.xrecoff) { LWLockRelease(WALInsertLock); + LWLockRelease(CheckpointStartLock); LWLockRelease(CheckpointLock); END_CRIT_SECTION(); return; @@ -3258,11 +3268,13 @@ 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. */ |