diff --git a/src/backend/utils/adt/windowfuncs.c b/src/backend/utils/adt/windowfuncs.c
index af13b8e53d..b87a624fb2 100644
--- a/src/backend/utils/adt/windowfuncs.c
+++ b/src/backend/utils/adt/windowfuncs.c
@@ -288,6 +288,15 @@ window_percent_rank_support(PG_FUNCTION_ARGS)
 {
 	Node	   *rawreq = (Node *) PG_GETARG_POINTER(0);
 
+	if (IsA(rawreq, SupportRequestWFuncMonotonic))
+	{
+		SupportRequestWFuncMonotonic *req = (SupportRequestWFuncMonotonic *) rawreq;
+
+		/* percent_rank() is monotonically increasing */
+		req->monotonic = MONOTONICFUNC_INCREASING;
+		PG_RETURN_POINTER(req);
+	}
+
 	if (IsA(rawreq, SupportRequestOptimizeWindowClause))
 	{
 		SupportRequestOptimizeWindowClause *req = (SupportRequestOptimizeWindowClause *) rawreq;
@@ -362,6 +371,15 @@ window_cume_dist_support(PG_FUNCTION_ARGS)
 {
 	Node	   *rawreq = (Node *) PG_GETARG_POINTER(0);
 
+	if (IsA(rawreq, SupportRequestWFuncMonotonic))
+	{
+		SupportRequestWFuncMonotonic *req = (SupportRequestWFuncMonotonic *) rawreq;
+
+		/* cume_dist() is monotonically increasing */
+		req->monotonic = MONOTONICFUNC_INCREASING;
+		PG_RETURN_POINTER(req);
+	}
+
 	if (IsA(rawreq, SupportRequestOptimizeWindowClause))
 	{
 		SupportRequestOptimizeWindowClause *req = (SupportRequestOptimizeWindowClause *) rawreq;
@@ -465,6 +483,18 @@ window_ntile_support(PG_FUNCTION_ARGS)
 {
 	Node	   *rawreq = (Node *) PG_GETARG_POINTER(0);
 
+	if (IsA(rawreq, SupportRequestWFuncMonotonic))
+	{
+		SupportRequestWFuncMonotonic *req = (SupportRequestWFuncMonotonic *) rawreq;
+
+		/*
+		 * ntile() is monotonically increasing as the number of buckets cannot
+		 * change after the first call
+		 */
+		req->monotonic = MONOTONICFUNC_INCREASING;
+		PG_RETURN_POINTER(req);
+	}
+
 	if (IsA(rawreq, SupportRequestOptimizeWindowClause))
 	{
 		SupportRequestOptimizeWindowClause *req = (SupportRequestOptimizeWindowClause *) rawreq;
diff --git a/src/test/regress/expected/window.out b/src/test/regress/expected/window.out
index 26e2df6da5..747608e3c1 100644
--- a/src/test/regress/expected/window.out
+++ b/src/test/regress/expected/window.out
@@ -3766,19 +3766,20 @@ SELECT * FROM
           count(salary) OVER (PARTITION BY depname || '') c1, -- w1
           row_number() OVER (PARTITION BY depname) rn, -- w2
           count(*) OVER (PARTITION BY depname) c2, -- w2
-          count(*) OVER (PARTITION BY '' || depname) c3 -- w3
+          count(*) OVER (PARTITION BY '' || depname) c3, -- w3
+          ntile(2) OVER (PARTITION BY depname) nt -- w2
    FROM empsalary
-) e WHERE rn <= 1 AND c1 <= 3;
-                                        QUERY PLAN                                         
--------------------------------------------------------------------------------------------
+) e WHERE rn <= 1 AND c1 <= 3 AND nt < 2;
+                                          QUERY PLAN                                           
+-----------------------------------------------------------------------------------------------
  Subquery Scan on e
    ->  WindowAgg
-         Filter: ((row_number() OVER (?)) <= 1)
+         Filter: (((row_number() OVER (?)) <= 1) AND ((ntile(2) OVER (?)) < 2))
          Run Condition: (count(empsalary.salary) OVER (?) <= 3)
          ->  Sort
                Sort Key: (((empsalary.depname)::text || ''::text))
                ->  WindowAgg
-                     Run Condition: (row_number() OVER (?) <= 1)
+                     Run Condition: ((row_number() OVER (?) <= 1) AND (ntile(2) OVER (?) < 2))
                      ->  Sort
                            Sort Key: empsalary.depname
                            ->  WindowAgg
@@ -3793,13 +3794,14 @@ SELECT * FROM
           count(salary) OVER (PARTITION BY depname || '') c1, -- w1
           row_number() OVER (PARTITION BY depname) rn, -- w2
           count(*) OVER (PARTITION BY depname) c2, -- w2
-          count(*) OVER (PARTITION BY '' || depname) c3 -- w3
+          count(*) OVER (PARTITION BY '' || depname) c3, -- w3
+          ntile(2) OVER (PARTITION BY depname) nt -- w2
    FROM empsalary
-) e WHERE rn <= 1 AND c1 <= 3;
-  depname  | empno | salary | enroll_date | c1 | rn | c2 | c3 
------------+-------+--------+-------------+----+----+----+----
- personnel |     5 |   3500 | 12-10-2007  |  2 |  1 |  2 |  2
- sales     |     3 |   4800 | 08-01-2007  |  3 |  1 |  3 |  3
+) e WHERE rn <= 1 AND c1 <= 3 AND nt < 2;
+  depname  | empno | salary | enroll_date | c1 | rn | c2 | c3 | nt 
+-----------+-------+--------+-------------+----+----+----+----+----
+ personnel |     5 |   3500 | 12-10-2007  |  2 |  1 |  2 |  2 |  1
+ sales     |     3 |   4800 | 08-01-2007  |  3 |  1 |  3 |  3 |  1
 (2 rows)
 
 -- Tests to ensure we don't push down the run condition when it's not valid to
diff --git a/src/test/regress/sql/window.sql b/src/test/regress/sql/window.sql
index b7bd0a83da..1009b438de 100644
--- a/src/test/regress/sql/window.sql
+++ b/src/test/regress/sql/window.sql
@@ -1220,9 +1220,10 @@ SELECT * FROM
           count(salary) OVER (PARTITION BY depname || '') c1, -- w1
           row_number() OVER (PARTITION BY depname) rn, -- w2
           count(*) OVER (PARTITION BY depname) c2, -- w2
-          count(*) OVER (PARTITION BY '' || depname) c3 -- w3
+          count(*) OVER (PARTITION BY '' || depname) c3, -- w3
+          ntile(2) OVER (PARTITION BY depname) nt -- w2
    FROM empsalary
-) e WHERE rn <= 1 AND c1 <= 3;
+) e WHERE rn <= 1 AND c1 <= 3 AND nt < 2;
 
 -- Ensure we correctly filter out all of the run conditions from each window
 SELECT * FROM
@@ -1230,9 +1231,10 @@ SELECT * FROM
           count(salary) OVER (PARTITION BY depname || '') c1, -- w1
           row_number() OVER (PARTITION BY depname) rn, -- w2
           count(*) OVER (PARTITION BY depname) c2, -- w2
-          count(*) OVER (PARTITION BY '' || depname) c3 -- w3
+          count(*) OVER (PARTITION BY '' || depname) c3, -- w3
+          ntile(2) OVER (PARTITION BY depname) nt -- w2
    FROM empsalary
-) e WHERE rn <= 1 AND c1 <= 3;
+) e WHERE rn <= 1 AND c1 <= 3 AND nt < 2;
 
 -- Tests to ensure we don't push down the run condition when it's not valid to
 -- do so.