Strange FDW plan change.

Author: Alexander Korotkov

contrib/postgres_fdw/expected/postgres_fdw.out

@@ -2781,16 +2781,17 @@ select c2, sum(c1) from ft2 group by c2 having avg(c1) < 500 and sum(c1) < 49800
 -- Unshippable HAVING clause will be evaluated locally, and other qual in HAVING clause is pushed down
 explain (verbose, costs off)
 select count(*) from (select c5, count(c1) from ft1 group by c5, sqrt(c2) having (avg(c1) / avg(c1)) * random() <= 1 and avg(c1) < 500) x;
-                                                              QUERY PLAN                                                               
----------------------------------------------------------------------------------------------------------------------------------------
+                                                                 QUERY PLAN                                                                  
+---------------------------------------------------------------------------------------------------------------------------------------------
  Aggregate
    Output: count(*)
-   ->  Foreign Scan
-         Output: ft1.c5, NULL::bigint, (sqrt((ft1.c2)::double precision))
-         Filter: (((((avg(ft1.c1)) / (avg(ft1.c1))))::double precision * random()) <= '1'::double precision)
-         Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT c5, NULL::bigint, sqrt(c2), avg("C 1") FROM "S 1"."T 1" GROUP BY 1, 3 HAVING ((avg("C 1") < 500::numeric))
-(7 rows)
+   ->  Subquery Scan on x
+         ->  Foreign Scan
+               Output: ft1.c5, NULL::bigint, (sqrt((ft1.c2)::double precision))
+               Filter: (((((avg(ft1.c1)) / (avg(ft1.c1))))::double precision * random()) <= '1'::double precision)
+               Relations: Aggregate on (public.ft1)
+               Remote SQL: SELECT c5, NULL::bigint, sqrt(c2), avg("C 1") FROM "S 1"."T 1" GROUP BY 1, 3 HAVING ((avg("C 1") < 500::numeric))
+(8 rows)
 
 select count(*) from (select c5, count(c1) from ft1 group by c5, sqrt(c2) having (avg(c1) / avg(c1)) * random() <= 1 and avg(c1) < 500) x;
  count