Remove some recursion in optimizer and clean up some code there.

src/backend/optimizer/path/allpaths.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/allpaths.c,v 1.13 1997/09/08 21:44:44 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/allpaths.c,v 1.14 1997/12/21 05:18:18 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -44,7 +44,7 @@ int32		_use_geqo_rels_ = GEQO_RELS;
 
 
 static void find_rel_paths(Query *root, List *rels);
-static List *find_join_paths(Query *root, List *outer_rels, int levels_left);
+static List *find_join_paths(Query *root, List *outer_rels, int levels_needed);
 
 /*
  * find-paths--
@@ -56,14 +56,14 @@ static List *find_join_paths(Query *root, List *outer_rels, int levels_left);
 List	   *
 find_paths(Query *root, List *rels)
 {
-	int			levels_left;
+	int			levels_needed;
 
 	/*
 	 * Set the number of join (not nesting) levels yet to be processed.
 	 */
-	levels_left = length(rels);
+	levels_needed = length(rels);
 
-	if (levels_left <= 0)
+	if (levels_needed <= 0)
 		return NIL;
 
 	/*
@@ -71,13 +71,13 @@ find_paths(Query *root, List *rels)
 	 */
 	find_rel_paths(root, rels);
 
-	if (levels_left <= 1)
+	if (levels_needed <= 1)
 	{
 
 		/*
 		 * Unsorted single relation, no more processing is required.
 		 */
-		return (rels);
+		return rels;
 	}
 	else
 	{
@@ -88,7 +88,7 @@ find_paths(Query *root, List *rels)
 		 */
 		set_rest_relselec(root, rels);
 
-		return (find_join_paths(root, rels, levels_left - 1));
+		return find_join_paths(root, rels, levels_needed);
 	}
 }
 
@@ -165,17 +165,16 @@ find_rel_paths(Query *root, List *rels)
  * 'outer-rels' is the current list of relations for which join paths
  *				are to be found, i.e., he current list of relations that
  *				have already been derived.
- * 'levels-left' is the current join level being processed, where '1' is
+ * 'levels-needed' is the number of iterations needed
- *				the "last" level
  *
  * Returns the final level of join relations, i.e., the relation that is
- * the result of joining all the original relations togehter.
+ * the result of joining all the original relations together.
  */
 static List *
-find_join_paths(Query *root, List *outer_rels, int levels_left)
+find_join_paths(Query *root, List *outer_rels, int levels_needed)
 {
 	List	   *x;
-	List	   *new_rels;
+	List	   *new_rels = NIL;
 	Rel		   *rel;
 
 	/*******************************************
@@ -190,6 +189,8 @@ find_join_paths(Query *root, List *outer_rels, int levels_left)
 	 * rest will be deprecated in case of GEQO *
 	 *******************************************/
 
+	 while (--levels_needed)
+	 {
 		/*
 		 * Determine all possible pairs of relations to be joined at this
 		 * level. Determine paths for joining these relation pairs and modify
@@ -199,7 +200,7 @@ find_join_paths(Query *root, List *outer_rels, int levels_left)
 	
 		find_all_join_paths(root, new_rels);
 	
-	new_rels = prune_joinrels(new_rels);
+		prune_joinrels(new_rels);
 	
 #if 0
 	
@@ -232,7 +233,7 @@ find_join_paths(Query *root, List *outer_rels, int levels_left)
 				rel->size = compute_rel_size(rel);
 			rel->width = compute_rel_width(rel);
 	
-/*#define OPTIMIZER_DEBUG*/
+	/*#define OPTIMIZER_DEBUG*/
 #ifdef OPTIMIZER_DEBUG
 			printf("levels left: %d\n", levels_left);
 			debug_print_rel(root, rel);
@@ -258,21 +259,14 @@ find_join_paths(Query *root, List *outer_rels, int levels_left)
 		{
 			root->join_relation_list_ = new_rels;
 		}
+		if (!BushyPlanFlag)
+			outer_rels = new_rels;
+	}
 
-	if (levels_left == 1)
-	{
 	if (BushyPlanFlag)
-			return (final_join_rels(outer_rels));
+		return final_join_rels(outer_rels);
 	else
-			return (new_rels);
+		return new_rels;
-	}
-	else
-	{
-		if (BushyPlanFlag)
-			return (find_join_paths(root, outer_rels, levels_left - 1));
-		else
-			return (find_join_paths(root, new_rels, levels_left - 1));
-	}
 }
 
 /*****************************************************************************

src/backend/optimizer/path/prune.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/prune.c,v 1.6 1997/09/08 21:45:08 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/prune.c,v 1.7 1997/12/21 05:18:21 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -29,23 +29,21 @@ static List *prune_joinrel(Rel *rel, List *other_rels);
 /*
  * prune-joinrels--
  *	  Removes any redundant relation entries from a list of rel nodes
- *	  'rel-list'.
+ *	  'rel-list'.  Obviosly, the first relation can't be a duplicate.
  *
  * Returns the resulting list.
  *
  */
-List	   *
+void
 prune_joinrels(List *rel_list)
 {
-	List	   *temp_list = NIL;
+	List	   *i;
 
-	if (rel_list != NIL)
+	/*
-	{
+	 *	rel_list can shorten while running as duplicate relations are deleted
-		temp_list = lcons(lfirst(rel_list),
+	 */
-				   prune_joinrels(prune_joinrel((Rel *) lfirst(rel_list),
+	foreach(i, rel_list)
-												lnext(rel_list))));
+		lnext(i) = prune_joinrel((Rel *) lfirst(i), lnext(i));
-	}
-	return (temp_list);
 }
 
 /*
@@ -62,28 +60,39 @@ prune_joinrels(List *rel_list)
 static List *
 prune_joinrel(Rel *rel, List *other_rels)
 {
-	List	   *i = NIL;
+	List	*cur = NIL;
-	List	   *t_list = NIL;
+	List	*return_list = NIL;
-	List	   *temp_node = NIL;
-	Rel		   *other_rel = (Rel *) NULL;
 
-	foreach(i, other_rels)
+	/* find first relation that doesn't match */
+	foreach(cur, other_rels)
 	{
-		other_rel = (Rel *) lfirst(i);
+		Rel	*other_rel = (Rel *) lfirst(cur);
+
+		if (!same(rel->relids, other_rel->relids))
+			break;
+	}
+
+	/* we now know cur doesn't match, or is NIL */
+	return_list = cur;
+	
+	/* remove relations that do match, we use lnext so we can remove easily */
+	if (cur != NIL)
+	{
+		while (lnext(cur) != NIL)
+		{
+			Rel	*other_rel = (Rel *) lfirst(lnext(cur));
+
 			if (same(rel->relids, other_rel->relids))
 			{
 				rel->pathlist = add_pathlist(rel,
 											 rel->pathlist,
 											 other_rel->pathlist);
-			t_list = nconc(t_list, NIL);		/* XXX is this right ? */
+				lnext(cur) = lnext(lnext(cur)); /* delete it */
 			}
-		else
+			cur = lnext(cur);
-		{
-			temp_node = lcons(other_rel, NIL);
-			t_list = nconc(t_list, temp_node);
 		}
 	}
-	return (t_list);
+	return return_list;
 }
 
 /*

src/backend/optimizer/prep/prepunion.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.11 1997/12/20 07:59:33 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.12 1997/12/21 05:18:28 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -236,9 +236,13 @@ plan_union_query(List *relids,
 		new_root->uniqueFlag = NULL;
 		new_root->sortClause = NULL;
 		new_root->groupClause = NULL;
+		if (new_root->qry_numAgg != 0)
+		{
 			new_root->qry_numAgg = 0;
+			pfree(new_root->qry_aggs);
 			new_root->qry_aggs = NULL;
 			del_agg_tlist_references(new_root->targetList);
+		}
 		fix_parsetree_attnums(rt_index,
 							  rt_entry->relid,
 							  relid,

src/include/optimizer/paths.h

@@ -7,7 +7,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: paths.h,v 1.5 1997/11/26 01:13:47 momjian Exp $
+ * $Id: paths.h,v 1.6 1997/12/21 05:18:48 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -92,7 +92,7 @@ extern List *final_join_rels(List *join_rel_list);
 /*
  * prototypes for path/prune.c
  */
-extern List *prune_joinrels(List *rel_list);
+extern void prune_joinrels(List *rel_list);
 extern void prune_rel_paths(List *rel_list);
 extern Path *prune_rel_path(Rel *rel, Path *unorderedpath);
 extern List *merge_joinrels(List *rel_list1, List *rel_list2);