diff options
Diffstat (limited to 'src/backend/access/transam/xlog.c')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 32 |
1 files changed, 1 insertions, 31 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index ba029397f87..03440cbf48b 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.252 2006/10/18 22:44:11 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.253 2006/11/05 22:42:08 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -5344,36 +5344,6 @@ GetLastSegSwitchTime(void) } /* - * GetRecentNextXid - get the nextXid value saved by the most recent checkpoint - * - * This is currently used only by the autovacuum daemon. To check for - * impending XID wraparound, autovac needs an approximate idea of the current - * XID counter, and it needs it before choosing which DB to attach to, hence - * before it sets up a PGPROC, hence before it can take any LWLocks. But it - * has attached to shared memory, and so we can let it reach into the shared - * ControlFile structure and pull out the last checkpoint nextXID. - * - * Since we don't take any sort of lock, we have to assume that reading a - * TransactionId is atomic ... but that assumption is made elsewhere, too, - * and in any case the worst possible consequence of a bogus result is that - * autovac issues an unnecessary database-wide VACUUM. - * - * Note: we could also choose to read ShmemVariableCache->nextXid in an - * unlocked fashion, thus getting a more up-to-date result; but since that - * changes far more frequently than the controlfile checkpoint copy, it would - * pose a far higher risk of bogus result if we did have a nonatomic-read - * problem. - * - * A (theoretically) completely safe answer is to read the actual pg_control - * file into local process memory, but that certainly seems like overkill. - */ -TransactionId -GetRecentNextXid(void) -{ - return ControlFile->checkPointCopy.nextXid; -} - -/* * GetNextXidAndEpoch - get the current nextXid value and associated epoch * * This is exported for use by code that would like to have 64-bit XIDs. |