diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c
index 8b04d40d36d..879dcb4608e 100644
--- a/src/backend/optimizer/path/pathkeys.c
+++ b/src/backend/optimizer/path/pathkeys.c
@@ -2154,14 +2154,31 @@ right_merge_direction(PlannerInfo *root, PathKey *pathkey)
  * Because we the have the possibility of incremental sort, a prefix list of
  * keys is potentially useful for improving the performance of the requested
  * ordering. Thus we return 0, if no valuable keys are found, or the number
- * of leading keys shared by the list and the requested ordering..
+ * of leading keys shared by the list and the requested ordering.
  */
 static int
 pathkeys_useful_for_ordering(PlannerInfo *root, List *pathkeys)
 {
 	int			n_common_pathkeys;
 
-	(void) pathkeys_count_contained_in(root->query_pathkeys, pathkeys,
+	(void) pathkeys_count_contained_in(root->sort_pathkeys, pathkeys,
+									   &n_common_pathkeys);
+
+	return n_common_pathkeys;
+}
+
+/*
+ * pathkeys_useful_for_windowing
+ *		Count the number of pathkeys that are useful for meeting the
+ *		query's desired sort order for window function evaluation.
+ */
+static int
+pathkeys_useful_for_windowing(PlannerInfo *root, List *pathkeys)
+{
+	int			n_common_pathkeys;
+
+	(void) pathkeys_count_contained_in(root->window_pathkeys,
+									   pathkeys,
 									   &n_common_pathkeys);
 
 	return n_common_pathkeys;
@@ -2276,6 +2293,9 @@ truncate_useless_pathkeys(PlannerInfo *root,
 
 	nuseful = pathkeys_useful_for_merging(root, rel, pathkeys);
 	nuseful2 = pathkeys_useful_for_ordering(root, pathkeys);
+	if (nuseful2 > nuseful)
+		nuseful = nuseful2;
+	nuseful2 = pathkeys_useful_for_windowing(root, pathkeys);
 	if (nuseful2 > nuseful)
 		nuseful = nuseful2;
 	nuseful2 = pathkeys_useful_for_grouping(root, pathkeys);
diff --git a/src/test/regress/expected/window.out b/src/test/regress/expected/window.out
index a2867f477f0..9e2f53726f5 100644
--- a/src/test/regress/expected/window.out
+++ b/src/test/regress/expected/window.out
@@ -4537,6 +4537,22 @@ WHERE first_emp = 1 OR last_emp = 1;
  sales     |     4 |   4800 | 08-08-2007  |         3 |        1
 (6 rows)
 
+CREATE INDEX empsalary_salary_empno_idx ON empsalary (salary, empno);
+SET enable_seqscan = 0;
+-- Ensure no sorting is done and that the IndexScan maintains all pathkeys
+-- useful for the final sort order.
+EXPLAIN (COSTS OFF)
+SELECT salary, empno, row_number() OVER (ORDER BY salary) rn
+FROM empsalary
+ORDER BY salary, empno;
+                             QUERY PLAN                              
+---------------------------------------------------------------------
+ WindowAgg
+   Window: w1 AS (ORDER BY salary ROWS UNBOUNDED PRECEDING)
+   ->  Index Only Scan using empsalary_salary_empno_idx on empsalary
+(3 rows)
+
+RESET enable_seqscan;
 -- cleanup
 DROP TABLE empsalary;
 -- test user-defined window function with named args and default args
diff --git a/src/test/regress/sql/window.sql b/src/test/regress/sql/window.sql
index 85fc621c8db..37d837a2f66 100644
--- a/src/test/regress/sql/window.sql
+++ b/src/test/regress/sql/window.sql
@@ -1522,6 +1522,19 @@ SELECT * FROM
    FROM empsalary) emp
 WHERE first_emp = 1 OR last_emp = 1;
 
+CREATE INDEX empsalary_salary_empno_idx ON empsalary (salary, empno);
+
+SET enable_seqscan = 0;
+
+-- Ensure no sorting is done and that the IndexScan maintains all pathkeys
+-- useful for the final sort order.
+EXPLAIN (COSTS OFF)
+SELECT salary, empno, row_number() OVER (ORDER BY salary) rn
+FROM empsalary
+ORDER BY salary, empno;
+
+RESET enable_seqscan;
+
 -- cleanup
 DROP TABLE empsalary;