From e5b1eed7c916bbe747ee86da815ebe4ea8bdd643 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 12 Sep 2008 14:56:19 +0000 Subject: [PATCH] Skip opfamily check in eclass_matches_any_index() when the index isn't a btree. We can't easily tell whether clauses generated from the equivalence class could be used with such an index, so just assume that they might be. This bit of over-optimization prevented use of non-btree indexes for nestloop inner indexscans, in any case where the join uses an equality operator that is also a btree operator --- which in particular is typically true for hash indexes. Noted while trying to test the current hash index patch. --- src/backend/optimizer/path/indxpath.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c index 8a2e808cc30..3100c92d3d8 100644 --- a/src/backend/optimizer/path/indxpath.c +++ b/src/backend/optimizer/path/indxpath.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.227 2008/02/07 17:53:53 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.227.2.1 2008/09/12 14:56:19 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1584,7 +1584,18 @@ eclass_matches_any_index(EquivalenceClass *ec, EquivalenceMember *em, { Oid curFamily = families[0]; - if (list_member_oid(ec->ec_opfamilies, curFamily) && + /* + * If it's a btree index, we can reject it if its opfamily isn't + * compatible with the EC, since no clause generated from the + * EC could be used with the index. For non-btree indexes, + * we can't easily tell whether clauses generated from the EC + * could be used with the index, so only check for expression + * match. This might mean we return "true" for a useless index, + * but that will just cause some wasted planner cycles; it's + * better than ignoring useful indexes. + */ + if ((index->relam != BTREE_AM_OID || + list_member_oid(ec->ec_opfamilies, curFamily)) && match_index_to_operand((Node *) em->em_expr, indexcol, index)) return true;