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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2007-03-30 00:13:05 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2007-03-30 00:13:05 +0000 |
| commit | 0e95abd64cd3d68da4e9134554ede4badcd106d4 (patch) | |
| tree | fae6a30fc7f1209556d873200b2665e860ffbfdd /src | |
| parent | 2dd336bba56d9caa7bcbca550fba34423f8d71e6 (diff) | |
| download | postgresql-0e95abd64cd3d68da4e9134554ede4badcd106d4.tar.gz postgresql-0e95abd64cd3d68da4e9134554ede4badcd106d4.zip | |
Fix oversight in coding of _bt_start_vacuum: we can't assume that the LWLock
will be released by transaction abort before _bt_end_vacuum gets called.
If either of these "can't happen" errors actually happened, we'd freeze up
trying to acquire an already-held lock. Latest word is that this does
not explain Martin Pitt's trouble report, but it still looks like a bug.
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/nbtree/nbtutils.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c index a562ee6cbd2..47abb5750dd 100644 --- a/src/backend/access/nbtree/nbtutils.c +++ b/src/backend/access/nbtree/nbtutils.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtutils.c,v 1.79 2006/10/04 00:29:49 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtutils.c,v 1.79.2.1 2007/03/30 00:13:05 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -998,13 +998,25 @@ _bt_start_vacuum(Relation rel) vac = &btvacinfo->vacuums[i]; if (vac->relid.relId == rel->rd_lockInfo.lockRelId.relId && vac->relid.dbId == rel->rd_lockInfo.lockRelId.dbId) + { + /* + * Unlike most places in the backend, we have to explicitly + * release our LWLock before throwing an error. This is because + * we expect _bt_end_vacuum() to be called before transaction + * abort cleanup can run to release LWLocks. + */ + LWLockRelease(BtreeVacuumLock); elog(ERROR, "multiple active vacuums for index \"%s\"", RelationGetRelationName(rel)); + } } /* OK, add an entry */ if (btvacinfo->num_vacuums >= btvacinfo->max_vacuums) + { + LWLockRelease(BtreeVacuumLock); elog(ERROR, "out of btvacinfo slots"); + } vac = &btvacinfo->vacuums[btvacinfo->num_vacuums]; vac->relid = rel->rd_lockInfo.lockRelId; vac->cycleid = result; |