minor_change_on_v3_Restore-preprocess_groupclause.diff

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index d6a1fb8e..801d9f6d 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -2852,15 +2852,13 @@ preprocess_groupclause(PlannerInfo *root, List *force)
 {
 	Query	   *parse = root->parse;
 	List	   *new_groupclause = NIL;
-	ListCell   *sl;
-	ListCell   *gl;
+	ListCell	*gl;
 
 	/* For grouping sets, we need to force the ordering */
-	if (force)
+	if (force != NIL)
 	{
-		foreach(sl, force)
+		foreach_int(ref, force)
 		{
-			Index		ref = lfirst_int(sl);
 			SortGroupClause *cl = get_sortgroupref_clause(ref, parse->groupClause);
 
 			new_groupclause = lappend(new_groupclause, cl);
@@ -2879,10 +2877,8 @@ preprocess_groupclause(PlannerInfo *root, List *force)
 	 *
 	 * This code assumes that the sortClause contains no duplicate items.
 	 */
-	foreach(sl, parse->sortClause)
+	foreach_node(SortGroupClause, sc, parse->sortClause)
 	{
-		SortGroupClause *sc = lfirst_node(SortGroupClause, sl);
-
 		foreach(gl, parse->groupClause)
 		{
 			SortGroupClause *gc = lfirst_node(SortGroupClause, gl);
@@ -2908,10 +2904,8 @@ preprocess_groupclause(PlannerInfo *root, List *force)
 	 * implemented using incremental sort.  Also, give up if there are any
 	 * non-sortable GROUP BY items, since then there's no hope anyway.
 	 */
-	foreach(gl, parse->groupClause)
+	foreach_node(SortGroupClause,gc, parse->groupClause)
 	{
-		SortGroupClause *gc = lfirst_node(SortGroupClause, gl);
-
 		if (list_member_ptr(new_groupclause, gc))
 			continue;			/* it matched an ORDER BY item */
 		if (!OidIsValid(gc->sortop))	/* give up, GROUP BY can't be sorted */
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index af8de421..2ba297c1 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -426,7 +426,7 @@ struct PlannerInfo
 	 * items to be proven redundant, implying that there is only one group
 	 * containing all the query's rows.  Hence, if you want to check whether
 	 * GROUP BY was specified, test for nonempty parse->groupClause, not for
-	 * nonempty processed_groupClause.  Optimiser chooses specific order of
+	 * nonempty processed_groupClause.  Optimizer chooses specific order of
 	 * group-by clauses during the upper paths generation process, attempting
 	 * to use different strategies to minimize number of sorts or engage
 	 * incremental sort.  See preprocess_groupclause() and