*** pgsql/src/backend/optimizer/path/allpaths.c	2009/06/11 14:48:58	1.183
--- pgsql/src/backend/optimizer/path/allpaths.c	2009/07/06 18:26:30	1.184
***************
*** 8,14 ****
   *
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.182 2009/04/19 19:46:33 tgl Exp $
   *
   *-------------------------------------------------------------------------
   */
--- 8,14 ----
   *
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.183 2009/06/11 14:48:58 momjian Exp $
   *
   *-------------------------------------------------------------------------
   */
***************
*** 29,34 ****
--- 29,35 ----
  #include "optimizer/plancat.h"
  #include "optimizer/planner.h"
  #include "optimizer/prep.h"
+ #include "optimizer/restrictinfo.h"
  #include "optimizer/var.h"
  #include "parser/parse_clause.h"
  #include "parser/parsetree.h"
*************** set_append_rel_pathlist(PlannerInfo *roo
*** 318,323 ****
--- 319,326 ----
  		int			childRTindex;
  		RangeTblEntry *childRTE;
  		RelOptInfo *childrel;
+ 		List	   *childquals;
+ 		Node	   *childqual;
  		Path	   *childpath;
  		ListCell   *parentvars;
  		ListCell   *childvars;
*************** set_append_rel_pathlist(PlannerInfo *roo
*** 342,351 ****
  		 * baserestrictinfo quals are needed before we can check for
  		 * constraint exclusion; so do that first and then check to see if we
  		 * can disregard this child.
  		 */
! 		childrel->baserestrictinfo = (List *)
! 			adjust_appendrel_attrs((Node *) rel->baserestrictinfo,
! 								   appinfo);
  
  		if (relation_excluded_by_constraints(root, childrel, childRTE))
  		{
--- 345,378 ----
  		 * baserestrictinfo quals are needed before we can check for
  		 * constraint exclusion; so do that first and then check to see if we
  		 * can disregard this child.
+ 		 *
+ 		 * As of 8.4, the child rel's targetlist might contain non-Var
+ 		 * expressions, which means that substitution into the quals
+ 		 * could produce opportunities for const-simplification, and perhaps
+ 		 * even pseudoconstant quals.  To deal with this, we strip the
+ 		 * RestrictInfo nodes, do the substitution, do const-simplification,
+ 		 * and then reconstitute the RestrictInfo layer.
  		 */
! 		childquals = get_all_actual_clauses(rel->baserestrictinfo);
! 		childquals = (List *) adjust_appendrel_attrs((Node *) childquals,
! 													 appinfo);
! 		childqual = eval_const_expressions(root, (Node *)
! 										   make_ands_explicit(childquals));
! 		if (childqual && IsA(childqual, Const) &&
! 			(((Const *) childqual)->constisnull ||
! 			 !DatumGetBool(((Const *) childqual)->constvalue)))
! 		{
! 			/*
! 			 * Restriction reduces to constant FALSE or constant NULL after
! 			 * substitution, so this child need not be scanned.
! 			 */
! 			set_dummy_rel_pathlist(childrel);
! 			continue;
! 		}
! 		childquals = make_ands_implicit((Expr *) childqual);
! 		childquals = make_restrictinfos_from_actual_clauses(root,
! 															childquals);
! 		childrel->baserestrictinfo = childquals;
  
  		if (relation_excluded_by_constraints(root, childrel, childRTE))
  		{