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Modify uses of RelationFlushRelation and RelationCacheInvalidate so that 

we *always* rebuild, rather than deleting, an invalidated relcache entry
that has positive refcount.  Otherwise an SI cache overrun leads to
dangling Relation pointers all over the place!
This commit is contained in:
Tom Lane 2000-01-29 19:51:59 +00:00
parent 98c6e81e94
commit 04103e00f1
2 changed files with 27 additions and 9 deletions
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9
src/backend/utils/cache/inval.c vendored
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/cache/inval.c,v 1.32 2000/01/26 05:57:17 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/cache/inval.c,v 1.33 2000/01/29 19:51:59 tgl Exp $
*
* Note - this code is real crufty...
*
@ -548,15 +548,16 @@ CacheIdInvalidate(Index cacheId,
/* --------------------------------
* ResetSystemCaches
*
* this blows away all tuples in the system catalog caches and
* all the cached relation descriptors (and closes the files too).
* This blows away all tuples in the system catalog caches and
* all the cached relation descriptors (and closes their files too).
* Relation descriptors that have positive refcounts are then rebuilt.
* --------------------------------
*/
static void
ResetSystemCaches()
{
ResetSystemCache();
RelationCacheInvalidate(false);
RelationCacheInvalidate(true);
}
/* --------------------------------

27
src/backend/utils/cache/relcache.c vendored
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.87 2000/01/26 05:57:17 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.88 2000/01/29 19:51:59 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1406,7 +1406,18 @@ RelationIdInvalidateRelationCacheByRelationId(Oid relationId)
*/
if (PointerIsValid(relation) && !relation->rd_myxactonly)
{
#if 1
/*
* Seems safest just to NEVER flush rels with positive refcounts.
* I think the code only had that proviso as a rather lame method of
* cleaning up unused relcache entries that had dangling refcounts
* (following elog(ERROR) with an open rel). Now we rely on
* RelationCacheAbort to clean up dangling refcounts, so there's no
* good reason to ever risk flushing a rel with positive refcount.
* IMHO anyway --- tgl 1/29/00.
*/
RelationFlushRelation(&relation, true);
#else
/*
* The boolean onlyFlushReferenceCountZero in RelationFlushReln()
* should be set to true when we are incrementing the command
@ -1414,6 +1425,7 @@ RelationIdInvalidateRelationCacheByRelationId(Oid relationId)
* can be determined by checking the current xaction status.
*/
RelationFlushRelation(&relation, CurrentXactInProgress());
#endif
}
}
@ -1436,7 +1448,7 @@ RelationFlushIndexes(Relation *r,
if (relation->rd_rel->relkind == RELKIND_INDEX && /* XXX style */
(!OidIsValid(accessMethodId) ||
relation->rd_rel->relam == accessMethodId))
RelationFlushRelation(&relation, false);
RelationFlushRelation(&relation, true);
}
#endif
@ -1469,9 +1481,14 @@ RelationIdInvalidateRelationCacheByAccessMethodId(Oid accessMethodId)
* Will blow away either all the cached relation descriptors or
* those that have a zero reference count.
*
* CAUTION: this is only called with onlyFlushReferenceCountZero=true
* at present, so that relation descriptors with positive refcounts
* are rebuilt rather than clobbered. It would only be safe to use a
* "false" parameter in a totally idle backend with no open relations.
*
* This is currently used only to recover from SI message buffer overflow,
* so onlyFlushReferenceCountZero is always false. We do not blow away
* transaction-local relations, since they cannot be targets of SI updates.
* so we do not blow away transaction-local relations; they cannot be
* targets of SI updates.
*/
void
RelationCacheInvalidate(bool onlyFlushReferenceCountZero)