First cut at planner support for bitmap index scans. Lots to do yet,

but the code is basically working.  Along the way, rewrite the entire
approach to processing OR index conditions, and make it work in join
cases for the first time ever.  orindxpath.c is now basically obsolete,
but I left it in for the time being to allow easy comparison testing
against the old implementation.

src/backend/optimizer/util/restrictinfo.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.32 2005/03/28 00:58:24 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.33 2005/04/22 21:58:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -31,7 +31,7 @@ static Expr *make_sub_restrictinfos(Expr *clause,
 static RestrictInfo *join_clause_is_redundant(Query *root,
 						 RestrictInfo *rinfo,
 						 List *reference_list,
-						 JoinType jointype);
+						 bool isouterjoin);
 
 
 /*
@@ -49,27 +49,19 @@ static RestrictInfo *join_clause_is_redundant(Query *root,
 RestrictInfo *
 make_restrictinfo(Expr *clause, bool is_pushed_down, bool valid_everywhere)
 {
-	Expr	   *orclause;
-
 	/*
 	 * If it's an OR clause, build a modified copy with RestrictInfos
 	 * inserted above each subclause of the top-level AND/OR structure.
 	 */
 	if (or_clause((Node *) clause))
-	{
-		orclause = make_sub_restrictinfos(clause,
-										  is_pushed_down,
-										  valid_everywhere);
-	}
-	else
-	{
-		/* Shouldn't be an AND clause, else AND/OR flattening messed up */
-		Assert(!and_clause((Node *) clause));
+		return (RestrictInfo *) make_sub_restrictinfos(clause,
+													   is_pushed_down,
+													   valid_everywhere);
 
-		orclause = NULL;
-	}
+	/* Shouldn't be an AND clause, else AND/OR flattening messed up */
+	Assert(!and_clause((Node *) clause));
 
-	return make_restrictinfo_internal(clause, orclause,
+	return make_restrictinfo_internal(clause, NULL,
 									  is_pushed_down, valid_everywhere);
 }
 
@@ -198,6 +190,12 @@ make_restrictinfo_internal(Expr *clause, Expr *orclause,
 
 /*
  * Recursively insert sub-RestrictInfo nodes into a boolean expression.
+ *
+ * We put RestrictInfos above simple (non-AND/OR) clauses and above
+ * sub-OR clauses, but not above sub-AND clauses, because there's no need.
+ * This may seem odd but it is closely related to the fact that we use
+ * implicit-AND lists at top level of RestrictInfo lists.  Only ORs and
+ * simple clauses are valid RestrictInfos.
  */
 static Expr *
 make_sub_restrictinfos(Expr *clause, bool is_pushed_down,
@@ -213,7 +211,10 @@ make_sub_restrictinfos(Expr *clause, bool is_pushed_down,
 							 make_sub_restrictinfos(lfirst(temp),
 													is_pushed_down,
 													valid_everywhere));
-		return make_orclause(orlist);
+		return (Expr *) make_restrictinfo_internal(clause,
+												   make_orclause(orlist),
+												   is_pushed_down,
+												   valid_everywhere);
 	}
 	else if (and_clause((Node *) clause))
 	{
@@ -314,7 +315,7 @@ get_actual_join_clauses(List *restrictinfo_list,
  */
 List *
 remove_redundant_join_clauses(Query *root, List *restrictinfo_list,
-							  JoinType jointype)
+							  bool isouterjoin)
 {
 	List	   *result = NIL;
 	ListCell   *item;
@@ -341,7 +342,7 @@ remove_redundant_join_clauses(Query *root, List *restrictinfo_list,
 		RestrictInfo *prevrinfo;
 
 		/* is it redundant with any prior clause? */
-		prevrinfo = join_clause_is_redundant(root, rinfo, result, jointype);
+		prevrinfo = join_clause_is_redundant(root, rinfo, result, isouterjoin);
 		if (prevrinfo == NULL)
 		{
 			/* no, so add it to result list */
@@ -377,7 +378,7 @@ List *
 select_nonredundant_join_clauses(Query *root,
 								 List *restrictinfo_list,
 								 List *reference_list,
-								 JoinType jointype)
+								 bool isouterjoin)
 {
 	List	   *result = NIL;
 	ListCell   *item;
@@ -387,7 +388,7 @@ select_nonredundant_join_clauses(Query *root,
 		RestrictInfo *rinfo = (RestrictInfo *) lfirst(item);
 
 		/* drop it if redundant with any reference clause */
-		if (join_clause_is_redundant(root, rinfo, reference_list, jointype) != NULL)
+		if (join_clause_is_redundant(root, rinfo, reference_list, isouterjoin) != NULL)
 			continue;
 
 		/* otherwise, add it to result list */
@@ -429,7 +430,7 @@ static RestrictInfo *
 join_clause_is_redundant(Query *root,
 						 RestrictInfo *rinfo,
 						 List *reference_list,
-						 JoinType jointype)
+						 bool isouterjoin)
 {
 	ListCell   *refitem;
 
@@ -463,7 +464,7 @@ join_clause_is_redundant(Query *root,
 				if (rinfo->left_pathkey == refrinfo->left_pathkey &&
 					rinfo->right_pathkey == refrinfo->right_pathkey &&
 					(rinfo->is_pushed_down == refrinfo->is_pushed_down ||
-					 !IS_OUTER_JOIN(jointype)))
+					 !isouterjoin))
 				{
 					/* Yup, it's redundant */
 					return refrinfo;