diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index 211ba65389..700cd0e16b 100644
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -3133,10 +3133,25 @@ create_agg_path(PlannerInfo *root,
 	pathnode->path.parallel_safe = rel->consider_parallel &&
 		subpath->parallel_safe;
 	pathnode->path.parallel_workers = subpath->parallel_workers;
+
 	if (aggstrategy == AGG_SORTED)
-		pathnode->path.pathkeys = subpath->pathkeys;	/* preserves order */
+	{
+		/*
+		 * Attempt to preserve the order of the subpath.  Additional pathkeys may
+		 * have been added in adjust_group_pathkeys_for_groupagg() to support ORDER
+		 * BY / DISTINCT aggregates.  Pathkeys added there belong to columns within
+		 * the aggregate function, so we must strip these additional pathkeys off as
+		 * those columns are unavailable above the aggregate node.
+		 */
+		if (list_length(subpath->pathkeys) > root->num_groupby_pathkeys)
+			pathnode->path.pathkeys = list_copy_head(subpath->pathkeys,
+													 root->num_groupby_pathkeys);
+		else
+			pathnode->path.pathkeys = subpath->pathkeys; /* preserves order */
+	}
 	else
 		pathnode->path.pathkeys = NIL;	/* output is unordered */
+
 	pathnode->subpath = subpath;
 
 	pathnode->aggstrategy = aggstrategy;