diff options
Diffstat (limited to 'src/backend/utils/cache/relcache.c')
| -rw-r--r-- | src/backend/utils/cache/relcache.c | 24 |
1 files changed, 13 insertions, 11 deletions
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c index f1140385883..66fb63b9e48 100644 --- a/src/backend/utils/cache/relcache.c +++ b/src/backend/utils/cache/relcache.c @@ -265,8 +265,10 @@ static void unlink_initfile(const char *initfilename); * This is used by RelationBuildDesc to find a pg_class * tuple matching targetRelId. The caller must hold at least * AccessShareLock on the target relid to prevent concurrent-update - * scenarios --- else our SnapshotNow scan might fail to find any - * version that it thinks is live. + * scenarios; it isn't guaranteed that all scans used to build the + * relcache entry will use the same snapshot. If, for example, + * an attribute were to be added after scanning pg_class and before + * scanning pg_attribute, relnatts wouldn't match. * * NB: the returned tuple has been copied into palloc'd storage * and must eventually be freed with heap_freetuple. @@ -305,7 +307,7 @@ ScanPgRelation(Oid targetRelId, bool indexOK) pg_class_desc = heap_open(RelationRelationId, AccessShareLock); pg_class_scan = systable_beginscan(pg_class_desc, ClassOidIndexId, indexOK && criticalRelcachesBuilt, - SnapshotNow, + NULL, 1, key); pg_class_tuple = systable_getnext(pg_class_scan); @@ -480,7 +482,7 @@ RelationBuildTupleDesc(Relation relation) pg_attribute_scan = systable_beginscan(pg_attribute_desc, AttributeRelidNumIndexId, criticalRelcachesBuilt, - SnapshotNow, + NULL, 2, skey); /* @@ -663,7 +665,7 @@ RelationBuildRuleLock(Relation relation) rewrite_tupdesc = RelationGetDescr(rewrite_desc); rewrite_scan = systable_beginscan(rewrite_desc, RewriteRelRulenameIndexId, - true, SnapshotNow, + true, NULL, 1, &key); while (HeapTupleIsValid(rewrite_tuple = systable_getnext(rewrite_scan))) @@ -1313,7 +1315,7 @@ LookupOpclassInfo(Oid operatorClassOid, ObjectIdGetDatum(operatorClassOid)); rel = heap_open(OperatorClassRelationId, AccessShareLock); scan = systable_beginscan(rel, OpclassOidIndexId, indexOK, - SnapshotNow, 1, skey); + NULL, 1, skey); if (HeapTupleIsValid(htup = systable_getnext(scan))) { @@ -1348,7 +1350,7 @@ LookupOpclassInfo(Oid operatorClassOid, ObjectIdGetDatum(opcentry->opcintype)); rel = heap_open(AccessMethodProcedureRelationId, AccessShareLock); scan = systable_beginscan(rel, AccessMethodProcedureIndexId, indexOK, - SnapshotNow, 3, skey); + NULL, 3, skey); while (HeapTupleIsValid(htup = systable_getnext(scan))) { @@ -3317,7 +3319,7 @@ AttrDefaultFetch(Relation relation) adrel = heap_open(AttrDefaultRelationId, AccessShareLock); adscan = systable_beginscan(adrel, AttrDefaultIndexId, true, - SnapshotNow, 1, &skey); + NULL, 1, &skey); found = 0; while (HeapTupleIsValid(htup = systable_getnext(adscan))) @@ -3384,7 +3386,7 @@ CheckConstraintFetch(Relation relation) conrel = heap_open(ConstraintRelationId, AccessShareLock); conscan = systable_beginscan(conrel, ConstraintRelidIndexId, true, - SnapshotNow, 1, skey); + NULL, 1, skey); while (HeapTupleIsValid(htup = systable_getnext(conscan))) { @@ -3487,7 +3489,7 @@ RelationGetIndexList(Relation relation) indrel = heap_open(IndexRelationId, AccessShareLock); indscan = systable_beginscan(indrel, IndexIndrelidIndexId, true, - SnapshotNow, 1, &skey); + NULL, 1, &skey); while (HeapTupleIsValid(htup = systable_getnext(indscan))) { @@ -3938,7 +3940,7 @@ RelationGetExclusionInfo(Relation indexRelation, conrel = heap_open(ConstraintRelationId, AccessShareLock); conscan = systable_beginscan(conrel, ConstraintRelidIndexId, true, - SnapshotNow, 1, skey); + NULL, 1, skey); found = false; while (HeapTupleIsValid(htup = systable_getnext(conscan))) |