1berry/postgres
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Don't try to run clauseless index scans on index types that don't support

Browse Source 
it.  Per report from Marinos Yannikos.
This commit is contained in:
Tom Lane 2005-04-20 21:48:22 +00:00
parent 387c398c37
commit 08008de909
1 changed files with 17 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
src/backend/optimizer/path/indxpath.c
View File

@ -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,