Restructure handling of inheritance queries so that they work with outer

joins, and clean things up a good deal at the same time.  Append plan node
no longer hacks on rangetable at runtime --- instead, all child tables are
given their own RT entries during planning.  Concept of multiple target
tables pushed up into execMain, replacing bug-prone implementation within
nodeAppend.  Planner now supports generating Append plans for inheritance
sets either at the top of the plan (the old way) or at the bottom.  Expanding
at the bottom is appropriate for tables used as sources, since they may
appear inside an outer join; but we must still expand at the top when the
target of an UPDATE or DELETE is an inheritance set, because we actually need
a different targetlist and junkfilter for each target table in that case.
Fortunately a target table can't be inside an outer join...  Bizarre mutual
recursion between union_planner and prepunion.c is gone --- in fact,
union_planner doesn't really have much to do with union queries anymore,
so I renamed it grouping_planner.

3 files changed, 330 insertions, 251 deletions

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index a865da61b92..4069ed66e58 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.99 2000/10/26 21:36:09 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.100 2000/11/12 00:36:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -32,35 +32,38 @@
 #include "utils/syscache.h"
 
 
-static List *switch_outer(List *clauses);
-static Scan *create_scan_node(Query *root, Path *best_path, List *tlist);
-static Join *create_join_node(Query *root, JoinPath *best_path, List *tlist);
-static SeqScan *create_seqscan_node(Path *best_path, List *tlist,
+static Scan *create_scan_plan(Query *root, Path *best_path);
+static Join *create_join_plan(Query *root, JoinPath *best_path);
+static Append *create_append_plan(Query *root, AppendPath *best_path);
+static SeqScan *create_seqscan_plan(Path *best_path, List *tlist,
 					List *scan_clauses);
-static IndexScan *create_indexscan_node(Query *root, IndexPath *best_path,
+static IndexScan *create_indexscan_plan(Query *root, IndexPath *best_path,
 					  List *tlist, List *scan_clauses);
-static TidScan *create_tidscan_node(TidPath *best_path, List *tlist,
+static TidScan *create_tidscan_plan(TidPath *best_path, List *tlist,
 					List *scan_clauses);
-static SubqueryScan *create_subqueryscan_node(Path *best_path,
+static SubqueryScan *create_subqueryscan_plan(Path *best_path,
 					  List *tlist, List *scan_clauses);
-static NestLoop *create_nestloop_node(NestPath *best_path, List *tlist,
+static NestLoop *create_nestloop_plan(NestPath *best_path, List *tlist,
 									  List *joinclauses, List *otherclauses,
-									  Plan *outer_node, List *outer_tlist,
-									  Plan *inner_node, List *inner_tlist);
-static MergeJoin *create_mergejoin_node(MergePath *best_path, List *tlist,
+									  Plan *outer_plan, List *outer_tlist,
+									  Plan *inner_plan, List *inner_tlist);
+static MergeJoin *create_mergejoin_plan(MergePath *best_path, List *tlist,
 										List *joinclauses, List *otherclauses,
-										Plan *outer_node, List *outer_tlist,
-										Plan *inner_node, List *inner_tlist);
-static HashJoin *create_hashjoin_node(HashPath *best_path, List *tlist,
+										Plan *outer_plan, List *outer_tlist,
+										Plan *inner_plan, List *inner_tlist);
+static HashJoin *create_hashjoin_plan(HashPath *best_path, List *tlist,
 									  List *joinclauses, List *otherclauses,
-									  Plan *outer_node, List *outer_tlist,
-									  Plan *inner_node, List *inner_tlist);
+									  Plan *outer_plan, List *outer_tlist,
+									  Plan *inner_plan, List *inner_tlist);
 static List *fix_indxqual_references(List *indexquals, IndexPath *index_path);
 static List *fix_indxqual_sublist(List *indexqual, int baserelid, Oid relam,
 					 Form_pg_index index);
 static Node *fix_indxqual_operand(Node *node, int baserelid,
 					 Form_pg_index index,
 					 Oid *opclass);
+static List *switch_outer(List *clauses);
+static void copy_path_costsize(Plan *dest, Path *src);
+static void copy_plan_costsize(Plan *dest, Plan *src);
 static SeqScan *make_seqscan(List *qptlist, List *qpqual, Index scanrelid);
 static IndexScan *make_indexscan(List *qptlist, List *qpqual, Index scanrelid,
 			   List *indxid, List *indxqual,
@@ -83,7 +86,6 @@ static MergeJoin *make_mergejoin(List *tlist,
 								 List *mergeclauses,
 								 Plan *lefttree, Plan *righttree,
 								 JoinType jointype);
-static void copy_path_costsize(Plan *dest, Path *src);
 
 /*
  * create_plan
@@ -98,13 +100,12 @@ static void copy_path_costsize(Plan *dest, Path *src);
  *
  *	  best_path is the best access path
  *
- *	  Returns the access plan.
+ *	  Returns a Plan tree.
  */
 Plan *
 create_plan(Query *root, Path *best_path)
 {
-	List	   *tlist = best_path->parent->targetlist;
-	Plan	   *plan_node = (Plan *) NULL;
+	Plan	   *plan;
 
 	switch (best_path->pathtype)
 	{
@@ -112,18 +113,22 @@ create_plan(Query *root, Path *best_path)
 		case T_SeqScan:
 		case T_TidScan:
 		case T_SubqueryScan:
-			plan_node = (Plan *) create_scan_node(root, best_path, tlist);
+			plan = (Plan *) create_scan_plan(root, best_path);
 			break;
 		case T_HashJoin:
 		case T_MergeJoin:
 		case T_NestLoop:
-			plan_node = (Plan *) create_join_node(root,
-												  (JoinPath *) best_path,
-												  tlist);
+			plan = (Plan *) create_join_plan(root,
+											 (JoinPath *) best_path);
+			break;
+		case T_Append:
+			plan = (Plan *) create_append_plan(root,
+											   (AppendPath *) best_path);
 			break;
 		default:
 			elog(ERROR, "create_plan: unknown pathtype %d",
 				 best_path->pathtype);
+			plan = NULL;		/* keep compiler quiet */
 			break;
 	}
 
@@ -131,30 +136,29 @@ create_plan(Query *root, Path *best_path)
 	/* sort clauses by cost/(1-selectivity) -- JMH 2/26/92 */
 	if (XfuncMode != XFUNC_OFF)
 	{
-		set_qpqual((Plan) plan_node,
-				   lisp_qsort(get_qpqual((Plan) plan_node),
+		set_qpqual((Plan) plan,
+				   lisp_qsort(get_qpqual((Plan) plan),
 							  xfunc_clause_compare));
 		if (XfuncMode != XFUNC_NOR)
 			/* sort the disjuncts within each clause by cost -- JMH 3/4/92 */
-			xfunc_disjunct_sort(plan_node->qpqual);
+			xfunc_disjunct_sort(plan->qpqual);
 	}
 #endif
 
-	return plan_node;
+	return plan;
 }
 
 /*
- * create_scan_node
- *	 Create a scan path for the parent relation of 'best_path'.
+ * create_scan_plan
+ *	 Create a scan plan for the parent relation of 'best_path'.
  *
- *	 tlist is the targetlist for the base relation scanned by 'best_path'
- *
- *	 Returns the scan node.
+ *	 Returns a Plan node.
  */
 static Scan *
-create_scan_node(Query *root, Path *best_path, List *tlist)
+create_scan_plan(Query *root, Path *best_path)
 {
-	Scan	   *node = NULL;
+	Scan	   *plan;
+	List	   *tlist = best_path->parent->targetlist;
 	List	   *scan_clauses;
 
 	/*
@@ -166,65 +170,64 @@ create_scan_node(Query *root, Path *best_path, List *tlist)
 	switch (best_path->pathtype)
 	{
 		case T_SeqScan:
-			node = (Scan *) create_seqscan_node(best_path,
+			plan = (Scan *) create_seqscan_plan(best_path,
 												tlist,
 												scan_clauses);
 			break;
 
 		case T_IndexScan:
-			node = (Scan *) create_indexscan_node(root,
+			plan = (Scan *) create_indexscan_plan(root,
 												  (IndexPath *) best_path,
 												  tlist,
 												  scan_clauses);
 			break;
 
 		case T_TidScan:
-			node = (Scan *) create_tidscan_node((TidPath *) best_path,
+			plan = (Scan *) create_tidscan_plan((TidPath *) best_path,
 												tlist,
 												scan_clauses);
 			break;
 
 		case T_SubqueryScan:
-			node = (Scan *) create_subqueryscan_node(best_path,
+			plan = (Scan *) create_subqueryscan_plan(best_path,
 													 tlist,
 													 scan_clauses);
 			break;
 
 		default:
-			elog(ERROR, "create_scan_node: unknown node type: %d",
+			elog(ERROR, "create_scan_plan: unknown node type: %d",
 				 best_path->pathtype);
+			plan = NULL;		/* keep compiler quiet */
 			break;
 	}
 
-	return node;
+	return plan;
 }
 
 /*
- * create_join_node
- *	  Create a join path for 'best_path' and(recursively) paths for its
+ * create_join_plan
+ *	  Create a join plan for 'best_path' and (recursively) plans for its
  *	  inner and outer paths.
  *
- *	  'tlist' is the targetlist for the join relation corresponding to
- *		'best_path'
- *
- *	  Returns the join node.
+ *	  Returns a Plan node.
  */
 static Join *
-create_join_node(Query *root, JoinPath *best_path, List *tlist)
+create_join_plan(Query *root, JoinPath *best_path)
 {
-	Plan	   *outer_node;
+	List	   *join_tlist = best_path->path.parent->targetlist;
+	Plan	   *outer_plan;
 	List	   *outer_tlist;
-	Plan	   *inner_node;
+	Plan	   *inner_plan;
 	List	   *inner_tlist;
 	List	   *joinclauses;
 	List	   *otherclauses;
-	Join	   *retval = NULL;
+	Join	   *plan;
 
-	outer_node = create_plan(root, best_path->outerjoinpath);
-	outer_tlist = outer_node->targetlist;
+	outer_plan = create_plan(root, best_path->outerjoinpath);
+	outer_tlist = outer_plan->targetlist;
 
-	inner_node = create_plan(root, best_path->innerjoinpath);
-	inner_tlist = inner_node->targetlist;
+	inner_plan = create_plan(root, best_path->innerjoinpath);
+	inner_tlist = inner_plan->targetlist;
 
 	if (IS_OUTER_JOIN(best_path->jointype))
 	{
@@ -241,38 +244,40 @@ create_join_node(Query *root, JoinPath *best_path, List *tlist)
 	switch (best_path->path.pathtype)
 	{
 		case T_MergeJoin:
-			retval = (Join *) create_mergejoin_node((MergePath *) best_path,
-													tlist,
-													joinclauses,
-													otherclauses,
-													outer_node,
-													outer_tlist,
-													inner_node,
-													inner_tlist);
+			plan = (Join *) create_mergejoin_plan((MergePath *) best_path,
+												  join_tlist,
+												  joinclauses,
+												  otherclauses,
+												  outer_plan,
+												  outer_tlist,
+												  inner_plan,
+												  inner_tlist);
 			break;
 		case T_HashJoin:
-			retval = (Join *) create_hashjoin_node((HashPath *) best_path,
-												   tlist,
-												   joinclauses,
-												   otherclauses,
-												   outer_node,
-												   outer_tlist,
-												   inner_node,
-												   inner_tlist);
+			plan = (Join *) create_hashjoin_plan((HashPath *) best_path,
+												 join_tlist,
+												 joinclauses,
+												 otherclauses,
+												 outer_plan,
+												 outer_tlist,
+												 inner_plan,
+												 inner_tlist);
 			break;
 		case T_NestLoop:
-			retval = (Join *) create_nestloop_node((NestPath *) best_path,
-												   tlist,
-												   joinclauses,
-												   otherclauses,
-												   outer_node,
-												   outer_tlist,
-												   inner_node,
-												   inner_tlist);
+			plan = (Join *) create_nestloop_plan((NestPath *) best_path,
+												 join_tlist,
+												 joinclauses,
+												 otherclauses,
+												 outer_plan,
+												 outer_tlist,
+												 inner_plan,
+												 inner_tlist);
 			break;
 		default:
-			elog(ERROR, "create_join_node: unknown node type: %d",
+			elog(ERROR, "create_join_plan: unknown node type: %d",
 				 best_path->path.pathtype);
+			plan = NULL;		/* keep compiler quiet */
+			break;
 	}
 
 #ifdef NOT_USED
@@ -283,14 +288,42 @@ create_join_node(Query *root, JoinPath *best_path, List *tlist)
 	 * JMH, 6/15/92
 	 */
 	if (get_loc_restrictinfo(best_path) != NIL)
-		set_qpqual((Plan) retval,
-				   nconc(get_qpqual((Plan) retval),
+		set_qpqual((Plan) plan,
+				   nconc(get_qpqual((Plan) plan),
 				   get_actual_clauses(get_loc_restrictinfo(best_path))));
 #endif
 
-	return retval;
+	return plan;
 }
 
+/*
+ * create_append_plan
+ *	  Create an Append plan for 'best_path' and (recursively) plans
+ *	  for its subpaths.
+ *
+ *	  Returns a Plan node.
+ */
+static Append *
+create_append_plan(Query *root, AppendPath *best_path)
+{
+	Append	   *plan;
+	List	   *tlist = best_path->path.parent->targetlist;
+	List	   *subplans = NIL;
+	List	   *subpaths;
+
+	foreach(subpaths, best_path->subpaths)
+	{
+		Path   *subpath = (Path *) lfirst(subpaths);
+		
+		subplans = lappend(subplans, create_plan(root, subpath));
+	}
+
+	plan = make_append(subplans, false, tlist);
+
+	return plan;
+}
+
+
 /*****************************************************************************
  *
  *	BASE-RELATION SCAN METHODS
@@ -299,14 +332,14 @@ create_join_node(Query *root, JoinPath *best_path, List *tlist)
 
 
 /*
- * create_seqscan_node
- *	 Returns a seqscan node for the base relation scanned by 'best_path'
+ * create_seqscan_plan
+ *	 Returns a seqscan plan for the base relation scanned by 'best_path'
  *	 with restriction clauses 'scan_clauses' and targetlist 'tlist'.
  */
 static SeqScan *
-create_seqscan_node(Path *best_path, List *tlist, List *scan_clauses)
+create_seqscan_plan(Path *best_path, List *tlist, List *scan_clauses)
 {
-	SeqScan    *scan_node;
+	SeqScan    *scan_plan;
 	Index		scan_relid;
 
 	/* there should be exactly one base rel involved... */
@@ -315,18 +348,18 @@ create_seqscan_node(Path *best_path, List *tlist, List *scan_clauses)
 
 	scan_relid = (Index) lfirsti(best_path->parent->relids);
 
-	scan_node = make_seqscan(tlist,
+	scan_plan = make_seqscan(tlist,
 							 scan_clauses,
 							 scan_relid);
 
-	copy_path_costsize(&scan_node->plan, best_path);
+	copy_path_costsize(&scan_plan->plan, best_path);
 
-	return scan_node;
+	return scan_plan;
 }
 
 /*
- * create_indexscan_node
- *	  Returns a indexscan node for the base relation scanned by 'best_path'
+ * create_indexscan_plan
+ *	  Returns a indexscan plan for the base relation scanned by 'best_path'
  *	  with restriction clauses 'scan_clauses' and targetlist 'tlist'.
  *
  * The indexqual of the path contains a sublist of implicitly-ANDed qual
@@ -338,7 +371,7 @@ create_seqscan_node(Path *best_path, List *tlist, List *scan_clauses)
  * scan.
  */
 static IndexScan *
-create_indexscan_node(Query *root,
+create_indexscan_plan(Query *root,
 					  IndexPath *best_path,
 					  List *tlist,
 					  List *scan_clauses)
@@ -348,7 +381,7 @@ create_indexscan_node(Query *root,
 	List	   *qpqual;
 	List	   *fixed_indxqual;
 	List	   *ixid;
-	IndexScan  *scan_node;
+	IndexScan  *scan_plan;
 	bool		lossy = false;
 
 	/* there should be exactly one base rel involved... */
@@ -433,7 +466,7 @@ create_indexscan_node(Query *root,
 	 */
 	fixed_indxqual = fix_indxqual_references(indxqual, best_path);
 
-	scan_node = make_indexscan(tlist,
+	scan_plan = make_indexscan(tlist,
 							   qpqual,
 							   baserelid,
 							   best_path->indexid,
@@ -441,22 +474,22 @@ create_indexscan_node(Query *root,
 							   indxqual,
 							   best_path->indexscandir);
 
-	copy_path_costsize(&scan_node->scan.plan, &best_path->path);
+	copy_path_costsize(&scan_plan->scan.plan, &best_path->path);
 	/* use the indexscan-specific rows estimate, not the parent rel's */
-	scan_node->scan.plan.plan_rows = best_path->rows;
+	scan_plan->scan.plan.plan_rows = best_path->rows;
 
-	return scan_node;
+	return scan_plan;
 }
 
 /*
- * create_tidscan_node
- *	 Returns a tidscan node for the base relation scanned by 'best_path'
+ * create_tidscan_plan
+ *	 Returns a tidscan plan for the base relation scanned by 'best_path'
  *	 with restriction clauses 'scan_clauses' and targetlist 'tlist'.
  */
 static TidScan *
-create_tidscan_node(TidPath *best_path, List *tlist, List *scan_clauses)
+create_tidscan_plan(TidPath *best_path, List *tlist, List *scan_clauses)
 {
-	TidScan    *scan_node;
+	TidScan    *scan_plan;
 	Index		scan_relid;
 
 	/* there should be exactly one base rel involved... */
@@ -465,28 +498,28 @@ create_tidscan_node(TidPath *best_path, List *tlist, List *scan_clauses)
 
 	scan_relid = (Index) lfirsti(best_path->path.parent->relids);
 
-	scan_node = make_tidscan(tlist,
+	scan_plan = make_tidscan(tlist,
 							 scan_clauses,
 							 scan_relid,
 							 best_path->tideval);
 
 	if (best_path->unjoined_relids)
-		scan_node->needRescan = true;
+		scan_plan->needRescan = true;
 
-	copy_path_costsize(&scan_node->scan.plan, &best_path->path);
+	copy_path_costsize(&scan_plan->scan.plan, &best_path->path);
 
-	return scan_node;
+	return scan_plan;
 }
 
 /*
- * create_subqueryscan_node
- *	 Returns a subqueryscan node for the base relation scanned by 'best_path'
+ * create_subqueryscan_plan
+ *	 Returns a subqueryscan plan for the base relation scanned by 'best_path'
  *	 with restriction clauses 'scan_clauses' and targetlist 'tlist'.
  */
 static SubqueryScan *
-create_subqueryscan_node(Path *best_path, List *tlist, List *scan_clauses)
+create_subqueryscan_plan(Path *best_path, List *tlist, List *scan_clauses)
 {
-	SubqueryScan *scan_node;
+	SubqueryScan *scan_plan;
 	Index		scan_relid;
 
 	/* there should be exactly one base rel involved... */
@@ -496,14 +529,12 @@ create_subqueryscan_node(Path *best_path, List *tlist, List *scan_clauses)
 
 	scan_relid = (Index) lfirsti(best_path->parent->relids);
 
-	scan_node = make_subqueryscan(tlist,
+	scan_plan = make_subqueryscan(tlist,
 								  scan_clauses,
 								  scan_relid,
 								  best_path->parent->subplan);
 
-	copy_path_costsize(&scan_node->scan.plan, best_path);
-
-	return scan_node;
+	return scan_plan;
 }
 
 /*****************************************************************************
@@ -528,18 +559,18 @@ create_subqueryscan_node(Path *best_path, List *tlist, List *scan_clauses)
  *****************************************************************************/
 
 static NestLoop *
-create_nestloop_node(NestPath *best_path,
+create_nestloop_plan(NestPath *best_path,
 					 List *tlist,
 					 List *joinclauses,
 					 List *otherclauses,
-					 Plan *outer_node,
+					 Plan *outer_plan,
 					 List *outer_tlist,
-					 Plan *inner_node,
+					 Plan *inner_plan,
 					 List *inner_tlist)
 {
-	NestLoop   *join_node;
+	NestLoop   *join_plan;
 
-	if (IsA(inner_node, IndexScan))
+	if (IsA(inner_plan, IndexScan))
 	{
 
 		/*
@@ -563,7 +594,7 @@ create_nestloop_node(NestPath *best_path,
 		 * and therefore has not itself done join_references renumbering
 		 * of the vars in its quals.
 		 */
-		IndexScan  *innerscan = (IndexScan *) inner_node;
+		IndexScan  *innerscan = (IndexScan *) inner_plan;
 		List	   *indxqualorig = innerscan->indxqualorig;
 
 		/* No work needed if indxqual refers only to its own relation... */
@@ -591,23 +622,23 @@ create_nestloop_node(NestPath *best_path,
 												  NIL,
 												  innerrel);
 			/* fix the inner qpqual too, if it has join clauses */
-			if (NumRelids((Node *) inner_node->qual) > 1)
-				inner_node->qual = join_references(inner_node->qual,
+			if (NumRelids((Node *) inner_plan->qual) > 1)
+				inner_plan->qual = join_references(inner_plan->qual,
 												   outer_tlist,
 												   NIL,
 												   innerrel);
 		}
 	}
-	else if (IsA(inner_node, TidScan))
+	else if (IsA(inner_plan, TidScan))
 	{
-		TidScan    *innerscan = (TidScan *) inner_node;
+		TidScan    *innerscan = (TidScan *) inner_plan;
 
 		innerscan->tideval = join_references(innerscan->tideval,
 											 outer_tlist,
 											 inner_tlist,
 											 innerscan->scan.scanrelid);
 	}
-	else if (IsA_Join(inner_node))
+	else if (IsA_Join(inner_plan))
 	{
 
 		/*
@@ -617,8 +648,8 @@ create_nestloop_node(NestPath *best_path,
 		 * join --- how can we estimate whether this is a good thing to
 		 * do?
 		 */
-		inner_node = (Plan *) make_material(inner_tlist,
-											inner_node);
+		inner_plan = (Plan *) make_material(inner_tlist,
+											inner_plan);
 	}
 
 	/*
@@ -633,30 +664,30 @@ create_nestloop_node(NestPath *best_path,
 								   inner_tlist,
 								   (Index) 0);
 
-	join_node = make_nestloop(tlist,
+	join_plan = make_nestloop(tlist,
 							  joinclauses,
 							  otherclauses,
-							  outer_node,
-							  inner_node,
+							  outer_plan,
+							  inner_plan,
 							  best_path->jointype);
 
-	copy_path_costsize(&join_node->join.plan, &best_path->path);
+	copy_path_costsize(&join_plan->join.plan, &best_path->path);
 
-	return join_node;
+	return join_plan;
 }
 
 static MergeJoin *
-create_mergejoin_node(MergePath *best_path,
+create_mergejoin_plan(MergePath *best_path,
 					  List *tlist,
 					  List *joinclauses,
 					  List *otherclauses,
-					  Plan *outer_node,
+					  Plan *outer_plan,
 					  List *outer_tlist,
-					  Plan *inner_node,
+					  Plan *inner_plan,
 					  List *inner_tlist)
 {
 	List	   *mergeclauses;
-	MergeJoin  *join_node;
+	MergeJoin  *join_plan;
 
 	mergeclauses = get_actual_clauses(best_path->path_mergeclauses);
 
@@ -692,15 +723,15 @@ create_mergejoin_node(MergePath *best_path,
 	 * necessary.  The sort cost was already accounted for in the path.
 	 */
 	if (best_path->outersortkeys)
-		outer_node = (Plan *)
+		outer_plan = (Plan *)
 			make_sort_from_pathkeys(outer_tlist,
-									outer_node,
+									outer_plan,
 									best_path->outersortkeys);
 
 	if (best_path->innersortkeys)
-		inner_node = (Plan *)
+		inner_plan = (Plan *)
 			make_sort_from_pathkeys(inner_tlist,
-									inner_node,
+									inner_plan,
 									best_path->innersortkeys);
 
 	/*
@@ -723,7 +754,7 @@ create_mergejoin_node(MergePath *best_path,
 	 * This check must agree with ExecMarkPos/ExecRestrPos in
 	 * executor/execAmi.c!
 	 */
-	switch (nodeTag(inner_node))
+	switch (nodeTag(inner_plan))
 	{
 		case T_SeqScan:
 		case T_IndexScan:
@@ -734,40 +765,40 @@ create_mergejoin_node(MergePath *best_path,
 
 		default:
 			/* Ooops, need to materialize the inner plan */
-			inner_node = (Plan *) make_material(inner_tlist,
-												inner_node);
+			inner_plan = (Plan *) make_material(inner_tlist,
+												inner_plan);
 			break;
 	}
 
 	/*
 	 * Now we can build the mergejoin node.
 	 */
-	join_node = make_mergejoin(tlist,
+	join_plan = make_mergejoin(tlist,
 							   joinclauses,
 							   otherclauses,
 							   mergeclauses,
-							   outer_node,
-							   inner_node,
+							   outer_plan,
+							   inner_plan,
 							   best_path->jpath.jointype);
 
-	copy_path_costsize(&join_node->join.plan, &best_path->jpath.path);
+	copy_path_costsize(&join_plan->join.plan, &best_path->jpath.path);
 
-	return join_node;
+	return join_plan;
 }
 
 static HashJoin *
-create_hashjoin_node(HashPath *best_path,
+create_hashjoin_plan(HashPath *best_path,
 					 List *tlist,
 					 List *joinclauses,
 					 List *otherclauses,
-					 Plan *outer_node,
+					 Plan *outer_plan,
 					 List *outer_tlist,
-					 Plan *inner_node,
+					 Plan *inner_plan,
 					 List *inner_tlist)
 {
 	List	   *hashclauses;
-	HashJoin   *join_node;
-	Hash	   *hash_node;
+	HashJoin   *join_plan;
+	Hash	   *hash_plan;
 	Node	   *innerhashkey;
 
 	/*
@@ -811,18 +842,18 @@ create_hashjoin_node(HashPath *best_path,
 	/*
 	 * Build the hash node and hash join node.
 	 */
-	hash_node = make_hash(inner_tlist, innerhashkey, inner_node);
-	join_node = make_hashjoin(tlist,
+	hash_plan = make_hash(inner_tlist, innerhashkey, inner_plan);
+	join_plan = make_hashjoin(tlist,
 							  joinclauses,
 							  otherclauses,
 							  hashclauses,
-							  outer_node,
-							  (Plan *) hash_node,
+							  outer_plan,
+							  (Plan *) hash_plan,
 							  best_path->jpath.jointype);
 
-	copy_path_costsize(&join_node->join.plan, &best_path->jpath.path);
+	copy_path_costsize(&join_plan->join.plan, &best_path->jpath.path);
 
-	return join_node;
+	return join_plan;
 }
 
 
@@ -1106,7 +1137,7 @@ copy_path_costsize(Plan *dest, Path *src)
  * but it helps produce more reasonable-looking EXPLAIN output.
  * (Some callers alter the info after copying it.)
  */
-void
+static void
 copy_plan_costsize(Plan *dest, Plan *src)
 {
 	if (src)
@@ -1128,6 +1159,10 @@ copy_plan_costsize(Plan *dest, Plan *src)
 
 /*****************************************************************************
  *
+ *	PLAN NODE BUILDING ROUTINES
+ *
+ * Some of these are exported because they are called to build plan nodes
+ * in contexts where we're not deriving the plan node from a path node.
  *
  *****************************************************************************/
 
@@ -1212,7 +1247,7 @@ make_subqueryscan(List *qptlist,
 	SubqueryScan *node = makeNode(SubqueryScan);
 	Plan	   *plan = &node->scan.plan;
 
-	/* cost should be inserted by caller */
+	copy_plan_costsize(plan, subplan);
 	plan->state = (EState *) NULL;
 	plan->targetlist = qptlist;
 	plan->qual = qpqual;
@@ -1225,6 +1260,39 @@ make_subqueryscan(List *qptlist,
 	return node;
 }
 
+Append *
+make_append(List *appendplans, bool isTarget, List *tlist)
+{
+	Append	   *node = makeNode(Append);
+	Plan	   *plan = &node->plan;
+	List	   *subnode;
+
+	/* compute costs from subplan costs */
+	plan->startup_cost = 0;
+	plan->total_cost = 0;
+	plan->plan_rows = 0;
+	plan->plan_width = 0;
+	foreach(subnode, appendplans)
+	{
+		Plan	   *subplan = (Plan *) lfirst(subnode);
+
+		if (subnode == appendplans)		/* first node? */
+			plan->startup_cost = subplan->startup_cost;
+		plan->total_cost += subplan->total_cost;
+		plan->plan_rows += subplan->plan_rows;
+		if (plan->plan_width < subplan->plan_width)
+			plan->plan_width = subplan->plan_width;
+	}
+	plan->state = (EState *) NULL;
+	plan->targetlist = tlist;
+	plan->qual = NIL;
+	plan->lefttree = NULL;
+	plan->righttree = NULL;
+	node->appendplans = appendplans;
+	node->isTarget = isTarget;
+
+	return node;
+}
 
 static NestLoop *
 make_nestloop(List *tlist,
diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c
index a9747b32799..1a923a506ff 100644
--- a/src/backend/optimizer/plan/planmain.c
+++ b/src/backend/optimizer/plan/planmain.c
@@ -14,7 +14,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.61 2000/10/05 19:11:29 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.62 2000/11/12 00:36:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -65,7 +65,8 @@ static Plan *subplanner(Query *root, List *flat_tlist,
  *	  tuple_fraction >= 1: tuple_fraction is the absolute number of tuples
  *		expected to be retrieved (ie, a LIMIT specification)
  * Note that while this routine and its subroutines treat a negative
- * tuple_fraction the same as 0, union_planner has a different interpretation.
+ * tuple_fraction the same as 0, grouping_planner has a different
+ * interpretation.
  *
  * Returns a query plan.
  *--------------------
@@ -125,9 +126,16 @@ query_planner(Query *root,
 	subplan = subplanner(root, var_only_tlist, tuple_fraction);
 
 	/*
-	 * Build a result node to control the plan if we have constant quals.
+	 * Build a result node to control the plan if we have constant quals,
+	 * or if the top-level plan node is one that cannot do expression
+	 * evaluation (it won't be able to evaluate the requested tlist).
+	 * Currently, the only plan node we might see here that falls into
+	 * that category is Append.
+	 *
+	 * XXX future improvement: if the given tlist is flat anyway, we don't
+	 * really need a Result node.
 	 */
-	if (constant_quals)
+	if (constant_quals || IsA(subplan, Append))
 	{
 
 		/*
@@ -325,8 +333,8 @@ subplanner(Query *root,
 
 	/*
 	 * Nothing for it but to sort the cheapest-total-cost path --- but we
-	 * let the caller do that.	union_planner has to be able to add a sort
-	 * node anyway, so no need for extra code here.  (Furthermore, the
+	 * let the caller do that.	grouping_planner has to be able to add a
+	 * sort node anyway, so no need for extra code here.  (Furthermore, the
 	 * given pathkeys might involve something we can't compute here, such
 	 * as an aggregate function...)
 	 */
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 67089e68d29..7a1151f0c9a 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.95 2000/11/09 02:46:16 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.96 2000/11/12 00:36:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -43,6 +43,8 @@ static void resolvenew_in_jointree(Node *jtnode, int varno, List *subtlist);
 static Node *preprocess_jointree(Query *parse, Node *jtnode);
 static Node *preprocess_expression(Query *parse, Node *expr, int kind);
 static void preprocess_qual_conditions(Query *parse, Node *jtnode);
+static Plan *inheritance_planner(Query *parse, List *inheritlist);
+static Plan *grouping_planner(Query *parse, double tuple_fraction);
 static List *make_subplanTargetList(Query *parse, List *tlist,
 					   AttrNumber **groupColIdx);
 static Plan *make_groupplan(List *group_tlist, bool tuplePerGroup,
@@ -65,7 +67,7 @@ planner(Query *parse)
 
 	/*
 	 * The planner can be called recursively (an example is when
-	 * eval_const_expressions tries to simplify an SQL function).
+	 * eval_const_expressions tries to pre-evaluate an SQL function).
 	 * So, these global state variables must be saved and restored.
 	 *
 	 * These vars cannot be moved into the Query structure since their
@@ -109,11 +111,14 @@ planner(Query *parse)
  *
  * parse is the querytree produced by the parser & rewriter.
  * tuple_fraction is the fraction of tuples we expect will be retrieved.
- * tuple_fraction is interpreted as explained for union_planner, below.
+ * tuple_fraction is interpreted as explained for grouping_planner, below.
  *
  * Basically, this routine does the stuff that should only be done once
- * per Query object.  It then calls union_planner, which may be called
- * recursively on the same Query node in order to handle inheritance.
+ * per Query object.  It then calls grouping_planner.  At one time,
+ * grouping_planner could be invoked recursively on the same Query object;
+ * that's not currently true, but we keep the separation between the two
+ * routines anyway, in case we need it again someday.
+ *
  * subquery_planner will be called recursively to handle sub-Query nodes
  * found within the query's expressions and rangetable.
  *
@@ -164,7 +169,7 @@ subquery_planner(Query *parse, double tuple_fraction)
 	}
 
 	/*
-	 * Do preprocessing on targetlist and quals.
+	 * Do expression preprocessing on targetlist and quals.
 	 */
 	parse->targetList = (List *)
 		preprocess_expression(parse, (Node *) parse->targetList,
@@ -176,17 +181,14 @@ subquery_planner(Query *parse, double tuple_fraction)
 											  EXPRKIND_HAVING);
 
 	/*
-	 * Do the main planning (potentially recursive for inheritance)
-	 */
-	plan = union_planner(parse, tuple_fraction);
-
-	/*
-	 * XXX should any more of union_planner's activity be moved here?
-	 *
-	 * That would take careful study of the interactions with prepunion.c,
-	 * but I suspect it would pay off in simplicity and avoidance of
-	 * wasted cycles.
+	 * Do the main planning.  If we have an inherited target relation,
+	 * that needs special processing, else go straight to grouping_planner.
 	 */
+	if (parse->resultRelation &&
+		(lst = expand_inherted_rtentry(parse, parse->resultRelation)) != NIL)
+		plan = inheritance_planner(parse, lst);
+	else
+		plan = grouping_planner(parse, tuple_fraction);
 
 	/*
 	 * If any subplans were generated, or if we're inside a subplan,
@@ -600,10 +602,65 @@ preprocess_qual_conditions(Query *parse, Node *jtnode)
 }
 
 /*--------------------
- * union_planner
- *	  Invokes the planner on union-type queries (both set operations and
- *	  appends produced by inheritance), recursing if necessary to get them
- *	  all, then processes normal plans.
+ * inheritance_planner
+ *	  Generate a plan in the case where the result relation is an
+ *	  inheritance set.
+ *
+ * We have to handle this case differently from cases where a source
+ * relation is an inheritance set.  Source inheritance is expanded at
+ * the bottom of the plan tree (see allpaths.c), but target inheritance
+ * has to be expanded at the top.  The reason is that for UPDATE, each
+ * target relation needs a different targetlist matching its own column
+ * set.  (This is not so critical for DELETE, but for simplicity we treat
+ * inherited DELETE the same way.)  Fortunately, the UPDATE/DELETE target
+ * can never be the nullable side of an outer join, so it's OK to generate
+ * the plan this way.
+ *
+ * parse is the querytree produced by the parser & rewriter.
+ * inheritlist is an integer list of RT indexes for the result relation set.
+ *
+ * Returns a query plan.
+ *--------------------
+ */
+static Plan *
+inheritance_planner(Query *parse, List *inheritlist)
+{
+	int			parentRTindex = parse->resultRelation;
+	Oid			parentOID = getrelid(parentRTindex, parse->rtable);
+	List	   *subplans = NIL;
+	List	   *tlist = NIL;
+	List	   *l;
+
+	foreach(l, inheritlist)
+	{
+		int		childRTindex = lfirsti(l);
+		Oid		childOID = getrelid(childRTindex, parse->rtable);
+		Query  *subquery;
+		Plan   *subplan;
+
+		/* Generate modified query with this rel as target */
+		subquery = (Query *) adjust_inherited_attrs((Node *) parse,
+													parentRTindex, parentOID,
+													childRTindex, childOID);
+		/* Generate plan */
+		subplan = grouping_planner(subquery, 0.0 /* retrieve all tuples */);
+		subplans = lappend(subplans, subplan);
+		/* Save preprocessed tlist from first rel for use in Append */
+		if (tlist == NIL)
+			tlist = subplan->targetlist;
+	}
+
+	/* Save the target-relations list for the executor, too */
+	parse->resultRelations = inheritlist;
+
+	return (Plan *) make_append(subplans, true, tlist);
+}
+
+/*--------------------
+ * grouping_planner
+ *	  Perform planning steps related to grouping, aggregation, etc.
+ *	  This primarily means adding top-level processing to the basic
+ *	  query plan produced by query_planner.
  *
  * parse is the querytree produced by the parser & rewriter.
  * tuple_fraction is the fraction of tuples we expect will be retrieved
@@ -621,18 +678,15 @@ preprocess_qual_conditions(Query *parse, Node *jtnode)
  * Returns a query plan.
  *--------------------
  */
-Plan *
-union_planner(Query *parse,
-			  double tuple_fraction)
+static Plan *
+grouping_planner(Query *parse, double tuple_fraction)
 {
 	List	   *tlist = parse->targetList;
-	Plan	   *result_plan = (Plan *) NULL;
-	AttrNumber *groupColIdx = NULL;
-	List	   *current_pathkeys = NIL;
+	Plan	   *result_plan;
+	List	   *current_pathkeys;
 	List	   *group_pathkeys;
 	List	   *sort_pathkeys;
-	Index		rt_index;
-	List	   *inheritors;
+	AttrNumber *groupColIdx = NULL;
 
 	if (parse->setOperations)
 	{
@@ -654,12 +708,13 @@ union_planner(Query *parse,
 		tlist = postprocess_setop_tlist(result_plan->targetlist, tlist);
 
 		/*
-		 * We leave current_pathkeys NIL indicating we do not know sort
+		 * We set current_pathkeys NIL indicating we do not know sort
 		 * order.  This is correct when the top set operation is UNION ALL,
 		 * since the appended-together results are unsorted even if the
 		 * subplans were sorted.  For other set operations we could be
-		 * smarter --- future improvement!
+		 * smarter --- room for future improvement!
 		 */
+		current_pathkeys = NIL;
 
 		/*
 		 * Calculate pathkeys that represent grouping/ordering
@@ -670,54 +725,6 @@ union_planner(Query *parse,
 		sort_pathkeys = make_pathkeys_for_sortclauses(parse->sortClause,
 													  tlist);
 	}
-	else if (find_inheritable_rt_entry(parse->rtable,
-									   &rt_index, &inheritors))
-	{
-		List	   *sub_tlist;
-
-		/*
-		 * Generate appropriate target list for subplan; may be different
-		 * from tlist if grouping or aggregation is needed.
-		 */
-		sub_tlist = make_subplanTargetList(parse, tlist, &groupColIdx);
-
-		/*
-		 * Recursively plan the subqueries needed for inheritance
-		 */
-		result_plan = plan_inherit_queries(parse, sub_tlist,
-										   rt_index, inheritors);
-
-		/*
-		 * Fix up outer target list.  NOTE: unlike the case for
-		 * non-inherited query, we pass the unfixed tlist to subplans,
-		 * which do their own fixing.  But we still want to fix the outer
-		 * target list afterwards. I *think* this is correct --- doing the
-		 * fix before recursing is definitely wrong, because
-		 * preprocess_targetlist() will do the wrong thing if invoked
-		 * twice on the same list. Maybe that is a bug? tgl 6/6/99
-		 */
-		tlist = preprocess_targetlist(tlist,
-									  parse->commandType,
-									  parse->resultRelation,
-									  parse->rtable);
-
-		if (parse->rowMarks)
-			elog(ERROR, "SELECT FOR UPDATE is not supported for inherit queries");
-
-		/*
-		 * We leave current_pathkeys NIL indicating we do not know sort
-		 * order of the Append-ed results.
-		 */
-
-		/*
-		 * Calculate pathkeys that represent grouping/ordering
-		 * requirements
-		 */
-		group_pathkeys = make_pathkeys_for_sortclauses(parse->groupClause,
-													   tlist);
-		sort_pathkeys = make_pathkeys_for_sortclauses(parse->sortClause,
-													  tlist);
-	}
 	else
 	{
 		List	   *sub_tlist;
@@ -938,10 +945,6 @@ union_planner(Query *parse,
 		current_pathkeys = parse->query_pathkeys;
 	}
 
-	/* query_planner returns NULL if it thinks plan is bogus */
-	if (!result_plan)
-		elog(ERROR, "union_planner: failed to create plan");
-
 	/*
 	 * We couldn't canonicalize group_pathkeys and sort_pathkeys before
 	 * running query_planner(), so do it now.
@@ -1057,7 +1060,7 @@ union_planner(Query *parse,
  * make_subplanTargetList
  *	  Generate appropriate target list when grouping is required.
  *
- * When union_planner inserts Aggregate and/or Group plan nodes above
+ * When grouping_planner inserts Aggregate and/or Group plan nodes above
  * the result of query_planner, we typically want to pass a different
  * target list to query_planner than the outer plan nodes should have.
  * This routine generates the correct target list for the subplan.