Fix GEQO to work again in CVS tip, by being more careful about memory

allocation in best_inner_indexscan().  While at it, simplify GEQO's
interface to the main planner --- make_join_rel() offers exactly the
API it really wants, whereas calling make_rels_by_clause_joins() and
make_rels_by_clauseless_joins() required jumping through hoops.
Rewrite gimme_tree for clarity (sometimes iteration is much better than
recursion), and approximately halve GEQO's runtime by recognizing that
tours of the forms (a,b,c,d,...) and (b,a,c,d,...) are equivalent
because of symmetry in make_join_rel().

1 files changed, 10 insertions, 6 deletions

diff --git a/src/backend/optimizer/path/joinrels.c b/src/backend/optimizer/path/joinrels.c
index 58772c0bc03..037733d5d72 100644
--- a/src/backend/optimizer/path/joinrels.c
+++ b/src/backend/optimizer/path/joinrels.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinrels.c,v 1.57 2002/06/20 20:29:30 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinrels.c,v 1.58 2002/12/16 21:30:30 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,8 +18,12 @@
 #include "optimizer/paths.h"
 
 
-static RelOptInfo *make_join_rel(Query *root, RelOptInfo *rel1,
-			  RelOptInfo *rel2, JoinType jointype);
+static List *make_rels_by_clause_joins(Query *root,
+									   RelOptInfo *old_rel,
+									   List *other_rels);
+static List *make_rels_by_clauseless_joins(Query *root,
+										   RelOptInfo *old_rel,
+										   List *other_rels);
 
 
 /*
@@ -246,7 +250,7 @@ make_rels_by_joins(Query *root, int level, List **joinrels)
  * no extra test for overlap for initial rels, since the is_subset test can
  * only succeed when other_rel is not already part of old_rel.)
  */
-List *
+static List *
 make_rels_by_clause_joins(Query *root,
 						  RelOptInfo *old_rel,
 						  List *other_rels)
@@ -297,7 +301,7 @@ make_rels_by_clause_joins(Query *root,
  * Currently, this is only used with initial rels in other_rels, but it would
  * work for joining to joinrels too.
  */
-List *
+static List *
 make_rels_by_clauseless_joins(Query *root,
 							  RelOptInfo *old_rel,
 							  List *other_rels)
@@ -392,7 +396,7 @@ make_jointree_rel(Query *root, Node *jtnode)
  *	   (The join rel may already contain paths generated from other
  *	   pairs of rels that add up to the same set of base rels.)
  */
-static RelOptInfo *
+RelOptInfo *
 make_join_rel(Query *root, RelOptInfo *rel1, RelOptInfo *rel2,
 			  JoinType jointype)
 {