build_subquery_pathkeys() was examining wrong copy of subquery target list,

causing it to fail to recognize the output ordering of subqueries that
contain set operations (UNION/INTERSECT/EXPECT).  Per example from Karel Zak.

diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c
index d6d83f7..65eb5cb 100644 (file)
--- a/src/backend/optimizer/path/pathkeys.c
+++ b/src/backend/optimizer/path/pathkeys.c
@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.55 2003/12/03 17:45:07 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.56 2004/04/07 17:42:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -757,6 +757,7 @@ build_subquery_pathkeys(Query *root, RelOptInfo *rel, Query *subquery)
        List       *retval = NIL;
        int                     retvallen = 0;
        int                     outer_query_keys = length(root->query_pathkeys);
+       List       *sub_tlist = rel->subplan->targetlist;
        List       *l;
 
        foreach(l, subquery->query_pathkeys)
@@ -789,7 +790,7 @@ build_subquery_pathkeys(Query *root, RelOptInfo *rel, Query *subquery)
                        Node       *sub_key = sub_item->key;
                        List       *k;
 
-                       foreach(k, subquery->targetList)
+                       foreach(k, sub_tlist)
                        {
                                TargetEntry *tle = (TargetEntry *) lfirst(k);