push-down-sort-into-inh-2.patch

diff -durpN pgsql.orig/src/backend/optimizer/path/allpaths.c pgsql/src/backend/optimizer/path/allpaths.c
--- pgsql.orig/src/backend/optimizer/path/allpaths.c	2010-03-29 00:59:32.000000000 +0200
+++ pgsql/src/backend/optimizer/path/allpaths.c	2010-08-25 11:56:10.000000000 +0200
@@ -170,6 +170,10 @@ set_rel_pathlist(PlannerInfo *root, RelO
 	{
 		/* It's an "append relation", process accordingly */
 		set_append_rel_pathlist(root, rel, rti, rte);
+#if 0
+		elog(NOTICE, "set_rel_pathlist setting sortClause to NIL");
+		root->parse->sortClause = NIL;
+#endif
 	}
 	else if (rel->rtekind == RTE_SUBQUERY)
 	{
@@ -282,8 +286,10 @@ static void
 set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
 						Index rti, RangeTblEntry *rte)
 {
+	Query	   *parse = root->parse;
 	int			parentRTindex = rti;
 	List	   *subpaths = NIL;
+	List	   *pathkeys = NIL;
 	double		parent_rows;
 	double		parent_size;
 	double	   *parent_attrsizes;
@@ -309,6 +315,14 @@ set_append_rel_pathlist(PlannerInfo *roo
 	nattrs = rel->max_attr - rel->min_attr + 1;
 	parent_attrsizes = (double *) palloc0(nattrs * sizeof(double));
 
+	if (parse->sortClause)
+	{
+		pathkeys = make_pathkeys_for_sortclauses(root,
+								parse->sortClause,
+								parse->targetList,
+								false);
+	}
+
 	/*
 	 * Generate access paths for each member relation, and pick the cheapest
 	 * path for each one.
@@ -423,6 +437,7 @@ set_append_rel_pathlist(PlannerInfo *roo
 		set_rel_pathlist(root, childrel, childRTindex, childRTE);
 
 		childpath = childrel->cheapest_total_path;
+
 		if (IsA(childpath, AppendPath))
 			subpaths = list_concat(subpaths,
 								   ((AppendPath *) childpath)->subpaths);
@@ -487,7 +502,7 @@ set_append_rel_pathlist(PlannerInfo *roo
 	 * the parent rel.	(Note: this is correct even if we have zero or one
 	 * live subpath due to constraint exclusion.)
 	 */
-	add_path(rel, (Path *) create_append_path(rel, subpaths));
+	add_path(rel, (Path *) create_append_path(rel, subpaths, pathkeys, true));
 
 	/* Select cheapest path (pretty easy in this case...) */
 	set_cheapest(rel);
@@ -507,7 +522,7 @@ set_dummy_rel_pathlist(RelOptInfo *rel)
 	rel->rows = 0;
 	rel->width = 0;
 
-	add_path(rel, (Path *) create_append_path(rel, NIL));
+	add_path(rel, (Path *) create_append_path(rel, NIL, NIL, false));
 
 	/* Select cheapest path (pretty easy in this case...) */
 	set_cheapest(rel);
diff -durpN pgsql.orig/src/backend/optimizer/path/joinpath.c pgsql/src/backend/optimizer/path/joinpath.c
--- pgsql.orig/src/backend/optimizer/path/joinpath.c	2010-04-19 09:42:28.000000000 +0200
+++ pgsql/src/backend/optimizer/path/joinpath.c	2010-08-25 10:51:50.000000000 +0200
@@ -955,7 +955,7 @@ best_appendrel_indexscan(PlannerInfo *ro
 		return NULL;
 
 	/* Form and return the completed Append path. */
-	return (Path *) create_append_path(rel, append_paths);
+	return (Path *) create_append_path(rel, append_paths, NIL, false);
 }
 
 /*
diff -durpN pgsql.orig/src/backend/optimizer/path/joinrels.c pgsql/src/backend/optimizer/path/joinrels.c
--- pgsql.orig/src/backend/optimizer/path/joinrels.c	2010-02-26 03:00:45.000000000 +0100
+++ pgsql/src/backend/optimizer/path/joinrels.c	2010-08-25 10:51:53.000000000 +0200
@@ -932,7 +932,7 @@ mark_dummy_rel(RelOptInfo *rel)
 	rel->pathlist = NIL;
 
 	/* Set up the dummy path */
-	add_path(rel, (Path *) create_append_path(rel, NIL));
+	add_path(rel, (Path *) create_append_path(rel, NIL, NIL, false));
 
 	/* Set or update cheapest_total_path */
 	set_cheapest(rel);
diff -durpN pgsql.orig/src/backend/optimizer/plan/createplan.c pgsql/src/backend/optimizer/plan/createplan.c
--- pgsql.orig/src/backend/optimizer/plan/createplan.c	2010-07-13 10:51:03.000000000 +0200
+++ pgsql/src/backend/optimizer/plan/createplan.c	2010-08-25 12:03:45.000000000 +0200
@@ -605,12 +605,40 @@ create_append_plan(PlannerInfo *root, Ap
 									NULL);
 	}
 
-	/* Normal case with multiple subpaths */
-	foreach(subpaths, best_path->subpaths)
+	if (best_path->inherited && root->parse->sortClause)
 	{
-		Path	   *subpath = (Path *) lfirst(subpaths);
+		/* Query from a partitioned table with ORDER BY */
+		foreach(subpaths, best_path->subpaths)
+		{
+			Path	   *subpath = (Path *) lfirst(subpaths);
+			Plan	   *subplan = create_plan_recurse(root, subpath);
+			ListCell   *parent_lc;
+			List	   *parent_tlist = root->parse->targetList;
+			ListCell   *child_lc;
+			List	   *child_tlist = subplan->targetlist;
 
-		subplans = lappend(subplans, create_plan_recurse(root, subpath));
+			/* Adjust ressortgroupref of the child targetlist */
+			forboth(parent_lc, parent_tlist, child_lc, child_tlist)
+			{
+				TargetEntry	   *parent_tle = (TargetEntry *) lfirst(parent_lc);
+				TargetEntry	   *child_tle  = (TargetEntry *) lfirst(child_lc);
+
+				child_tle->ressortgroupref = parent_tle->ressortgroupref;
+			}
+
+			subplans = lappend(subplans,
+							make_sort_from_sortclauses(root, root->parse->sortClause, subplan));
+		}
+	}
+	else
+	{
+		/* Normal case with multiple subpaths */
+		foreach(subpaths, best_path->subpaths)
+		{
+			Path	   *subpath = (Path *) lfirst(subpaths);
+
+			subplans = lappend(subplans, create_plan_recurse(root, subpath));
+		}
 	}
 
 	plan = make_append(subplans, tlist);
diff -durpN pgsql.orig/src/backend/optimizer/util/pathnode.c pgsql/src/backend/optimizer/util/pathnode.c
--- pgsql.orig/src/backend/optimizer/util/pathnode.c	2010-03-29 00:59:33.000000000 +0200
+++ pgsql/src/backend/optimizer/util/pathnode.c	2010-08-25 11:15:51.000000000 +0200
@@ -638,16 +638,17 @@ create_tidscan_path(PlannerInfo *root, R
  *	  pathnode.
  */
 AppendPath *
-create_append_path(RelOptInfo *rel, List *subpaths)
+create_append_path(RelOptInfo *rel, List *subpaths, List *pathkeys, bool inherited)
 {
 	AppendPath *pathnode = makeNode(AppendPath);
 	ListCell   *l;
 
 	pathnode->path.pathtype = T_Append;
 	pathnode->path.parent = rel;
-	pathnode->path.pathkeys = NIL;		/* result is always considered
+	pathnode->path.pathkeys = pathkeys;		/* result is always considered
 										 * unsorted */
 	pathnode->subpaths = subpaths;
+	pathnode->inherited = inherited;
 
 	pathnode->path.startup_cost = 0;
 	pathnode->path.total_cost = 0;
diff -durpN pgsql.orig/src/include/nodes/relation.h pgsql/src/include/nodes/relation.h
--- pgsql.orig/src/include/nodes/relation.h	2010-07-13 10:51:07.000000000 +0200
+++ pgsql/src/include/nodes/relation.h	2010-08-25 10:50:02.000000000 +0200
@@ -750,6 +750,7 @@ typedef struct AppendPath
 {
 	Path		path;
 	List	   *subpaths;		/* list of component Paths */
+	bool		inherited;
 } AppendPath;
 
 #define IS_DUMMY_PATH(p) \
diff -durpN pgsql.orig/src/include/optimizer/pathnode.h pgsql/src/include/optimizer/pathnode.h
--- pgsql.orig/src/include/optimizer/pathnode.h	2010-03-29 00:59:33.000000000 +0200
+++ pgsql/src/include/optimizer/pathnode.h	2010-08-25 10:50:23.000000000 +0200
@@ -46,7 +46,8 @@ extern BitmapOrPath *create_bitmap_or_pa
 					  List *bitmapquals);
 extern TidPath *create_tidscan_path(PlannerInfo *root, RelOptInfo *rel,
 					List *tidquals);
-extern AppendPath *create_append_path(RelOptInfo *rel, List *subpaths);
+extern AppendPath *create_append_path(RelOptInfo *rel, List *subpaths,
+					List *pathkeys, bool inherited);
 extern ResultPath *create_result_path(List *quals);
 extern MaterialPath *create_material_path(RelOptInfo *rel, Path *subpath);
 extern UniquePath *create_unique_path(PlannerInfo *root, RelOptInfo *rel,