From 08008de909688d59dc5988f49f2d2dcc4d5e8649 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 20 Apr 2005 21:48:22 +0000 Subject: [PATCH] Don't try to run clauseless index scans on index types that don't support it. Per report from Marinos Yannikos. --- src/backend/optimizer/path/indxpath.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c index 563bd17f41d..6c702c255d2 100644 --- a/src/backend/optimizer/path/indxpath.c +++ b/src/backend/optimizer/path/indxpath.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.147 2003/08/04 02:40:00 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.147.4.1 2005/04/20 21:48:22 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -172,11 +172,16 @@ create_index_paths(Query *root, RelOptInfo *rel) * 3. Compute pathkeys describing index's ordering, if any, then * see how many of them are actually useful for this query. */ - index_pathkeys = build_index_pathkeys(root, rel, index, - ForwardScanDirection); - index_is_ordered = (index_pathkeys != NIL); - useful_pathkeys = truncate_useless_pathkeys(root, rel, - index_pathkeys); + index_is_ordered = OidIsValid(index->ordering[0]); + if (index_is_ordered) + { + index_pathkeys = build_index_pathkeys(root, rel, index, + ForwardScanDirection); + useful_pathkeys = truncate_useless_pathkeys(root, rel, + index_pathkeys); + } + else + useful_pathkeys = NIL; /* * 4. Generate an indexscan path if there are relevant restriction @@ -186,10 +191,15 @@ create_index_paths(Query *root, RelOptInfo *rel) * If there is a predicate, consider it anyway since the index * predicate has already been found to match the query. The * selectivity of the predicate might alone make the index useful. + * + * Note: not all index AMs support scans with no restriction clauses. + * We assume here that the AM does so if and only if it supports + * ordered scans. (It would probably be better if there were a + * specific flag for this in pg_am, but there's not.) */ if (restrictclauses != NIL || useful_pathkeys != NIL || - index->indpred != NIL) + (index->indpred != NIL && index_is_ordered)) add_path(rel, (Path *) create_index_path(root, rel, index, restrictclauses, -- 2.39.5