From 8a3f745f160d8334ad978676828d3926ac949f43 Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Fri, 27 Jan 2012 20:08:34 +0200 Subject: [PATCH] Do not access indclass through Form_pg_index Normally, accessing variable-length members of catalog structures past the first one doesn't work at all. Here, it happened to work because indnatts was checked to be 1, and so the defined FormData_pg_index layout, using int2vector[1] and oidvector[1] for variable-length arrays, happened to match the actual memory layout. But it's a very fragile assumption, and it's not in a performance-critical path, so code it properly using heap_getattr() instead. bug analysis by Tom Lane --- src/backend/utils/cache/relcache.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c index d0138fc7e8..a59950e45a 100644 --- a/src/backend/utils/cache/relcache.c +++ b/src/backend/utils/cache/relcache.c @@ -3351,15 +3351,30 @@ RelationGetIndexList(Relation relation) while (HeapTupleIsValid(htup = systable_getnext(indscan))) { Form_pg_index index = (Form_pg_index) GETSTRUCT(htup); + Datum indclassDatum; + oidvector *indclass; + bool isnull; /* Add index's OID to result list in the proper order */ result = insert_ordered_oid(result, index->indexrelid); + /* + * indclass cannot be referenced directly through the C struct, because + * it comes after the variable-width indkey field. Must extract the + * datum the hard way... + */ + indclassDatum = heap_getattr(htup, + Anum_pg_index_indclass, + GetPgIndexDescriptor(), + &isnull); + Assert(!isnull); + indclass = (oidvector *) DatumGetPointer(indclassDatum); + /* Check to see if it is a unique, non-partial btree index on OID */ if (index->indnatts == 1 && index->indisunique && index->indimmediate && index->indkey.values[0] == ObjectIdAttributeNumber && - index->indclass.values[0] == OID_BTREE_OPS_OID && + indclass->values[0] == OID_BTREE_OPS_OID && heap_attisnull(htup, Anum_pg_index_indpred)) oidIndex = index->indexrelid; }