diff options
Diffstat (limited to 'src/backend/access/transam/xact.c')
| -rw-r--r-- | src/backend/access/transam/xact.c | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index b3d51a49ec..edbf9fb5d5 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.115.2.1 2002/03/15 19:20:43 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.115.2.2 2004/08/11 04:09:12 tgl Exp $ * * NOTES * Transaction aborts can now occur two ways: @@ -557,13 +557,27 @@ RecordTransactionCommit(void) */ if (MyXactMadeXLogEntry) { + bool madeTCentries; XLogRecPtr recptr; BufmgrCommit(); START_CRIT_SECTION(); - if (MyLastRecPtr.xrecoff != 0) + madeTCentries = (MyLastRecPtr.xrecoff != 0); + + /* + * We need to lock out checkpoint start between writing our XLOG + * record and updating pg_clog. Otherwise it is possible for the + * checkpoint to set REDO after the XLOG record but fail to flush the + * pg_clog update to disk, leading to loss of the transaction commit + * if we crash a little later. Slightly klugy fix for problem + * discovered 2004-08-10. + */ + if (madeTCentries) + LWLockAcquire(CheckpointStartLock, LW_SHARED); + + if (madeTCentries) { /* Need to emit a commit record */ XLogRecData rdata; @@ -610,9 +624,13 @@ RecordTransactionCommit(void) XLogFlush(recptr); /* Mark the transaction committed in clog, if needed */ - if (MyLastRecPtr.xrecoff != 0) + if (madeTCentries) TransactionIdCommit(xid); + /* Unlock checkpoint lock if we acquired it */ + if (madeTCentries) + LWLockRelease(CheckpointStartLock); + END_CRIT_SECTION(); } @@ -712,6 +730,8 @@ RecordTransactionAbort(void) * nowhere in permanent storage, so no one will ever care if it * committed.) We do not flush XLOG to disk in any case, since the * default assumption after a crash would be that we aborted, anyway. + * For the same reason, we don't need to worry about interlocking + * against checkpoint start. * * Extra check here is to catch case that we aborted partway through * RecordTransactionCommit ... |