Further cleanup for OR-of-AND WHERE-clauses. orindxpath can now handle

extracting from an AND subclause just those opclauses that are relevant
for a particular index.  For example, we can now consider using an index
on x to process WHERE (x = 1 AND y = 2) OR (x = 2 AND y = 4) OR ...

src/include/optimizer/paths.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: paths.h,v 1.39 2000/01/26 05:58:20 momjian Exp $
+ * $Id: paths.h,v 1.40 2000/02/05 18:26:07 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -38,8 +38,18 @@ extern List *create_index_paths(Query *root, RelOptInfo *rel, List *indices,
 				   List *joininfo_list);
 extern Oid indexable_operator(Expr *clause, Oid opclass, Oid relam,
 							  bool indexkey_on_left);
+extern List *extract_or_indexqual_conditions(RelOptInfo *rel,
+											 IndexOptInfo *index,
+											 Expr *orsubclause);
 extern List *expand_indexqual_conditions(List *indexquals);
 
+/*
+ * orindxpath.c
+ *	  additional routines for indexable OR clauses
+ */
+extern List *create_or_index_paths(Query *root, RelOptInfo *rel,
+								   List *clauses);
+
 /*
  * tidpath.h
  *	  routines to generate tid paths
@@ -52,12 +62,6 @@ extern List *create_tidscan_paths(Query *root, RelOptInfo *rel);
  */
 extern void update_rels_pathlist_for_joins(Query *root, List *joinrels);
 
-
-/*
- * orindxpath.c
- */
-extern List *create_or_index_paths(Query *root, RelOptInfo *rel, List *clauses);
-
 /*
  * pathkeys.c
  *	  utilities for matching and building path keys
@@ -100,7 +104,7 @@ extern bool nonoverlap_sets(List *s1, List *s2);
 extern bool is_subset(List *s1, List *s2);
 
 /*
- * prototypes for path/prune.c
+ * prune.c
  */
 extern void merge_rels_with_same_relids(List *rel_list);
 extern void rels_set_cheapest(Query *root, List *rel_list);