database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-27 23:21:58 +03:00
Code Activity

Fix nasty bug in optimization of multiway joins: optimizer

Browse Source 
would sometimes generate a plan that omitted a sort step before merge.
This commit is contained in:
Tom Lane
1999-04-03 00:18:28 +00:00
parent 97c52abcc5
commit ff38837fe9
4 changed files with 35 additions and 41 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
src/backend/optimizer/path/joinpath.c
View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinpath.c,v 1.32 1999/02/22 05:26:20 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinpath.c,v 1.33 1999/04/03 00:18:28 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -97,11 +97,11 @@ update_rels_pathlist_for_joins(Query *root, List *joinrels)
if (_enable_mergejoin_)
mergeinfo_list = group_clauses_by_order(joinrel->restrictinfo,
lfirsti(innerrel->relids));
innerrel->relids);
if (_enable_hashjoin_)
hashinfo_list = group_clauses_by_hashop(joinrel->restrictinfo,
lfirsti(innerrel->relids));
innerrel->relids);
/* need to flatten the relids list */
joinrel->relids = nconc(listCopy(outerrelids),
@ -173,12 +173,10 @@ best_innerjoin(List *join_paths, Relids outer_relids)
{
Path *path = (Path *) lfirst(join_path);
if (intMember(lfirsti(path->joinid), outer_relids)
&& ((cheapest == NULL ||
path_is_cheaper((Path *) lfirst(join_path), cheapest))))
{
cheapest = (Path *) lfirst(join_path);
}
if (intMember(lfirsti(path->joinid), outer_relids) &&
(cheapest == NULL ||
path_is_cheaper(path, cheapest)))
cheapest = path;
}
return cheapest;
}