diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
new file mode 100644
index a912174..ed87261
*** a/src/backend/optimizer/path/indxpath.c
--- b/src/backend/optimizer/path/indxpath.c
***************
*** 32,37 ****
--- 32,38 ----
  #include "optimizer/predtest.h"
  #include "optimizer/restrictinfo.h"
  #include "optimizer/var.h"
+ #include "parser/parsetree.h"
  #include "utils/builtins.h"
  #include "utils/bytea.h"
  #include "utils/lsyscache.h"
*************** static PathClauseUsage *classify_index_c
*** 135,141 ****
  static Relids get_bitmap_tree_required_outer(Path *bitmapqual);
  static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds);
  static int	find_list_position(Node *node, List **nodelist);
! static bool check_index_only(RelOptInfo *rel, IndexOptInfo *index);
  static double get_loop_count(PlannerInfo *root, Relids outer_relids);
  static void match_restriction_clauses_to_index(RelOptInfo *rel,
  								   IndexOptInfo *index,
--- 136,143 ----
  static Relids get_bitmap_tree_required_outer(Path *bitmapqual);
  static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds);
  static int	find_list_position(Node *node, List **nodelist);
! static bool check_index_only(PlannerInfo *root, RelOptInfo *rel,
! 				  IndexOptInfo *index, List *index_clauses);
  static double get_loop_count(PlannerInfo *root, Relids outer_relids);
  static void match_restriction_clauses_to_index(RelOptInfo *rel,
  								   IndexOptInfo *index,
*************** build_index_paths(PlannerInfo *root, Rel
*** 980,986 ****
  	 * index data retrieval anyway.
  	 */
  	index_only_scan = (scantype != ST_BITMAPSCAN &&
! 					   check_index_only(rel, index));
  
  	/*
  	 * 4. Generate an indexscan path if there are relevant restriction clauses
--- 982,988 ----
  	 * index data retrieval anyway.
  	 */
  	index_only_scan = (scantype != ST_BITMAPSCAN &&
! 					   check_index_only(root, rel, index, index_clauses));
  
  	/*
  	 * 4. Generate an indexscan path if there are relevant restriction clauses
*************** find_list_position(Node *node, List **no
*** 1741,1747 ****
   *		Determine whether an index-only scan is possible for this index.
   */
  static bool
! check_index_only(RelOptInfo *rel, IndexOptInfo *index)
  {
  	bool		result;
  	Bitmapset  *attrs_used = NULL;
--- 1743,1750 ----
   *		Determine whether an index-only scan is possible for this index.
   */
  static bool
! check_index_only(PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index,
! 				 List *index_clauses)
  {
  	bool		result;
  	Bitmapset  *attrs_used = NULL;
*************** check_index_only(RelOptInfo *rel, IndexO
*** 1758,1771 ****
  	/*
  	 * Check that all needed attributes of the relation are available from the
  	 * index.
- 	 *
- 	 * XXX this is overly conservative for partial indexes, since we will
- 	 * consider attributes involved in the index predicate as required even
- 	 * though the predicate won't need to be checked at runtime.  (The same is
- 	 * true for attributes used only in index quals, if we are certain that
- 	 * the index is not lossy.)  However, it would be quite expensive to
- 	 * determine that accurately at this point, so for now we take the easy
- 	 * way out.
  	 */
  
  	/*
--- 1761,1766 ----
*************** check_index_only(RelOptInfo *rel, IndexO
*** 1775,1785 ****
  	 */
  	pull_varattnos((Node *) rel->reltargetlist, rel->relid, &attrs_used);
  
! 	/* Add all the attributes used by restriction clauses. */
  	foreach(lc, rel->baserestrictinfo)
  	{
  		RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
  
  		pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
  	}
  
--- 1770,1805 ----
  	 */
  	pull_varattnos((Node *) rel->reltargetlist, rel->relid, &attrs_used);
  
! 	/*
! 	 * Add all the attributes required by restriction clauses.	This is
! 	 * essentially the same thing we do in create_indexscan_plan.
! 	 */
  	foreach(lc, rel->baserestrictinfo)
  	{
  		RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
  
+ 		Assert(IsA(rinfo, RestrictInfo));
+ 		if (rinfo->pseudoconstant)
+ 			continue;			/* we may drop pseudoconstants here */
+ 		if (list_member_ptr(index_clauses, rinfo))
+ 			continue;			/* simple duplicate */
+ 		if (is_redundant_derived_clause(rinfo, index_clauses))
+ 			continue;			/* derived from same EquivalenceClass */
+ 		if (!contain_mutable_functions((Node *) rinfo->clause))
+ 		{
+ 			List	   *clausel = list_make1(rinfo->clause);
+ 
+ 			if (predicate_implied_by(clausel, index_clauses))
+ 				continue;		/* provably implied by index_clauses */
+ 			if (index->indpred != NIL)
+ 			{
+ 				if (rel->relid != root->parse->resultRelation &&
+ 					get_parse_rowmark(root->parse, rel->relid) == NULL)
+ 					if (predicate_implied_by(clausel, index->indpred))
+ 						continue;		/* implied by index predicate */
+ 			}
+ 		}
+ 
  		pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
  	}
  
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
new file mode 100644
index 184d37a..d1b656f
*** a/src/backend/optimizer/plan/createplan.c
--- b/src/backend/optimizer/plan/createplan.c
*************** create_indexscan_plan(PlannerInfo *root,
*** 1215,1221 ****
  
  			if (predicate_implied_by(clausel, indexquals))
  				continue;		/* provably implied by indexquals */
! 			if (best_path->indexinfo->indpred)
  			{
  				if (baserelid != root->parse->resultRelation &&
  					get_parse_rowmark(root->parse, baserelid) == NULL)
--- 1215,1221 ----
  
  			if (predicate_implied_by(clausel, indexquals))
  				continue;		/* provably implied by indexquals */
! 			if (best_path->indexinfo->indpred != NIL)
  			{
  				if (baserelid != root->parse->resultRelation &&
  					get_parse_rowmark(root->parse, baserelid) == NULL)