diff --git a/contrib/postgres_fdw/deparse.c b/contrib/postgres_fdw/deparse.c
index 5c35414..92a82a0 100644
--- a/contrib/postgres_fdw/deparse.c
+++ b/contrib/postgres_fdw/deparse.c
@@ -98,7 +98,9 @@ typedef struct foreign_loc_cxt
 typedef struct deparse_expr_cxt
 {
 	PlannerInfo *root;			/* global planner state */
+
 	RelOptInfo *foreignrel;		/* the foreign relation we are planning for */
+	RelOptInfo *scanrel;		/* the underlying scan relation. */
 	StringInfo	buf;			/* output buffer to append to */
 	List	  **params_list;	/* exprs that will become remote Params */
 } deparse_expr_cxt;
@@ -903,6 +905,7 @@ deparseSelectStmtForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *rel,
 						List **retrieved_attrs, List **params_list)
 {
 	deparse_expr_cxt context;
+	PgFdwRelationInfo	*fpinfo = (PgFdwRelationInfo *)rel->fdw_private;
 
 	/* We handle all relations other than dead one. */
 	Assert(rel->reloptkind != RELOPT_DEADREL);
@@ -911,6 +914,7 @@ deparseSelectStmtForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *rel,
 	context.buf = buf;
 	context.root = root;
 	context.foreignrel = rel;
+	context.scanrel = (rel->reloptkind == RELOPT_UPPER_REL) ? fpinfo->outerrel : rel;
 	context.params_list = params_list;
 
 	/* Construct SELECT clause */
@@ -991,10 +995,11 @@ deparseSelectSql(List *tlist, List **retrieved_attrs, deparse_expr_cxt *context)
 }
 
 /*
- * Construct a FROM clause and WHERE clause, if any.  And append it to "buf".
- * The final output contains "SELECT ... FROM ... [WHERE ... ]".
+ * Construct a FROM clause and a WHERE clause, if any, and append those to
+ * "buf".
  *
- * remote_conds is the list of WHERE clauses, NIL if none.
+ * remote_conds is the list of clauses to be included in the WHERE clause,
+ * NIL if none.
  */
 static void
 deparseFromClause(List *remote_conds, deparse_expr_cxt *context)
@@ -1003,26 +1008,23 @@ deparseFromClause(List *remote_conds, deparse_expr_cxt *context)
 	RelOptInfo *foreignrel = context->foreignrel;
 	PlannerInfo *root = context->root;
 	PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
-	RelOptInfo *scan_rel = foreignrel;
+	RelOptInfo *scan_rel = context->scanrel;
 
 	/*
-	 * For aggregates the FROM clause will be build from underneath scan rel.
-	 * WHERE clause conditions too taken from there.
+	 * For aggregates the FROM clause will be built from the underneath scan
+	 * relation. Conditions in the WHERE clause are also taken from there.
 	 */
 	if (foreignrel->reloptkind == RELOPT_UPPER_REL)
 	{
 		PgFdwRelationInfo *ofpinfo;
 
 		ofpinfo = (PgFdwRelationInfo *) fpinfo->outerrel->fdw_private;
-		scan_rel = fpinfo->outerrel;
-		context->foreignrel = scan_rel;
 		remote_conds = ofpinfo->remote_conds;
 	}
 
 	/* Construct FROM clause */
 	appendStringInfoString(buf, " FROM ");
 	deparseFromExprForRel(buf, root, scan_rel,
-						  foreignrel->reloptkind == RELOPT_UPPER_REL ? true :
 						  (scan_rel->reloptkind == RELOPT_JOINREL),
 						  context->params_list);
 
@@ -1032,10 +1034,6 @@ deparseFromClause(List *remote_conds, deparse_expr_cxt *context)
 		appendStringInfo(buf, " WHERE ");
 		appendConditions(remote_conds, context);
 	}
-
-	/* Restore context's foreignrel */
-	if (foreignrel->reloptkind == RELOPT_UPPER_REL)
-		context->foreignrel = foreignrel;
 }
 
 /*
@@ -1138,14 +1136,14 @@ deparseTargetList(StringInfo buf,
 
 /*
  * Deparse the appropriate locking clause (FOR UPDATE or FOR SHARE) for a
- * given relation (context->foreignrel).
+ * given relation (context->scanrel).
  */
 static void
 deparseLockingClause(deparse_expr_cxt *context)
 {
 	StringInfo	buf = context->buf;
 	PlannerInfo *root = context->root;
-	RelOptInfo *rel = context->foreignrel;
+	RelOptInfo *rel = context->scanrel;
 	int			relid = -1;
 
 	while ((relid = bms_next_member(rel->relids, relid)) >= 0)
@@ -1366,6 +1364,7 @@ deparseFromExprForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
 
 			context.buf = buf;
 			context.foreignrel = foreignrel;
+			context.scanrel = foreignrel;
 			context.root = root;
 			context.params_list = params_list;
 
@@ -1534,6 +1533,7 @@ deparseDirectUpdateSql(StringInfo buf, PlannerInfo *root,
 	/* Set up context struct for recursion */
 	context.root = root;
 	context.foreignrel = baserel;
+	context.scanrel = baserel;
 	context.buf = buf;
 	context.params_list = params_list;
 
@@ -1618,6 +1618,7 @@ deparseDirectDeleteSql(StringInfo buf, PlannerInfo *root,
 	/* Set up context struct for recursion */
 	context.root = root;
 	context.foreignrel = baserel;
+	context.scanrel = baserel;
 	context.buf = buf;
 	context.params_list = params_list;
 
@@ -2044,10 +2045,10 @@ deparseExpr(Expr *node, deparse_expr_cxt *context)
 static void
 deparseVar(Var *node, deparse_expr_cxt *context)
 {
-	bool qualify_col = (context->foreignrel->reloptkind == RELOPT_JOINREL ||
-						context->foreignrel->reloptkind == RELOPT_UPPER_REL);
+	bool qualify_col = (context->scanrel->reloptkind == RELOPT_JOINREL ||
+						context->scanrel->reloptkind == RELOPT_UPPER_REL);
 
-	if (bms_is_member(node->varno, context->foreignrel->relids) &&
+	if (bms_is_member(node->varno, context->scanrel->relids) &&
 		node->varlevelsup == 0)
 		deparseColumnRef(context->buf, node->varno, node->varattno,
 						 context->root, qualify_col);
@@ -2824,42 +2825,45 @@ appendGroupByClause(List *tlist, deparse_expr_cxt *context)
 {
 	StringInfo	buf = context->buf;
 	Query	   *query = context->root->parse;
+	ListCell   *lc;
+	bool		first = true;
 
-	if (query->groupClause != NULL)
-	{
-		appendStringInfo(buf, " GROUP BY ");
+	/* Nothing to be done, if there's no GROUP BY clause in the query. */
+	if (!query->groupClause)
+		return;
 
-		if (query->groupingSets == NIL)
-		{
-			ListCell *lc;
-			bool	first = true;
+	appendStringInfo(buf, " GROUP BY ");
 
-			foreach(lc, query->groupClause)
-			{
-				SortGroupClause *grp = (SortGroupClause *) lfirst(lc);
-				Index	ref = grp->tleSortGroupRef;
-				TargetEntry *tle;
-				Expr   *expr;
+	/*
+	 * Queries with grouping sets are not pushed down, so we don't grouping
+	 * sets here.
+	 */
+	Assert(!query->groupingSets);
 
-				if (!first)
-					appendStringInfoString(buf, ", ");
-				first = false;
+	foreach(lc, query->groupClause)
+	{
+		SortGroupClause *grp = (SortGroupClause *) lfirst(lc);
+		Index	ref = grp->tleSortGroupRef;
+		TargetEntry *tle;
+		Expr   *expr;
+
+		if (!first)
+			appendStringInfoString(buf, ", ");
+		first = false;
 
-				tle = get_sortgroupref_tle(ref, tlist);
-				expr = tle->expr;
+		tle = get_sortgroupref_tle(ref, tlist);
+		expr = tle->expr;
 
-				if (expr && IsA(expr, Const))
-					deparseConst((Const *) expr, context);
-				else if (!expr || IsA(expr, Var))
-					deparseExpr(expr, context);
-				else
-				{
-					/* Must force parens for other expressions */
-					appendStringInfoString(buf, "(");
-					deparseExpr(expr, context);
-					appendStringInfoString(buf, ")");
-				}
-			}
+		if (expr && IsA(expr, Const))
+			deparseConst((Const *) expr, context);
+		else if (!expr || IsA(expr, Var))
+			deparseExpr(expr, context);
+		else
+		{
+			/* Must force parens for other expressions */
+			appendStringInfoString(buf, "(");
+			deparseExpr(expr, context);
+			appendStringInfoString(buf, ")");
 		}
 	}
 }
@@ -2875,7 +2879,7 @@ appendOrderByClause(List *pathkeys, deparse_expr_cxt *context)
 	ListCell   *lcell;
 	int			nestlevel;
 	char	   *delim = " ";
-	RelOptInfo *baserel = context->foreignrel;
+	RelOptInfo *baserel = context->scanrel;
 	StringInfo	buf = context->buf;
 
 	/* Make sure any constants in the exprs are printed portably */
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 6ba1895..8079071 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -861,12 +861,12 @@ CREATE OPERATOR === (
 -- built-in operators and functions can be shipped for remote execution
 EXPLAIN (VERBOSE, COSTS OFF)
   SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = abs(t1.c2);
-                                   QUERY PLAN                                    
----------------------------------------------------------------------------------
+                                QUERY PLAN                                 
+---------------------------------------------------------------------------
  Foreign Scan
    Output: (count(c3))
    Relations: Aggregate on (public.ft1 t1)
-   Remote SQL: SELECT count(r1.c3) FROM "S 1"."T 1" r1 WHERE (("C 1" = abs(c2)))
+   Remote SQL: SELECT count(c3) FROM "S 1"."T 1" WHERE (("C 1" = abs(c2)))
 (4 rows)
 
 SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = abs(t1.c2);
@@ -877,12 +877,12 @@ SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = abs(t1.c2);
 
 EXPLAIN (VERBOSE, COSTS OFF)
   SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = t1.c2;
-                                 QUERY PLAN                                 
-----------------------------------------------------------------------------
+                              QUERY PLAN                              
+----------------------------------------------------------------------
  Foreign Scan
    Output: (count(c3))
    Relations: Aggregate on (public.ft1 t1)
-   Remote SQL: SELECT count(r1.c3) FROM "S 1"."T 1" r1 WHERE (("C 1" = c2))
+   Remote SQL: SELECT count(c3) FROM "S 1"."T 1" WHERE (("C 1" = c2))
 (4 rows)
 
 SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = t1.c2;
@@ -935,12 +935,12 @@ ALTER SERVER loopback OPTIONS (ADD extensions 'postgres_fdw');
 -- ... now they can be shipped
 EXPLAIN (VERBOSE, COSTS OFF)
   SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = postgres_fdw_abs(t1.c2);
-                                             QUERY PLAN                                              
------------------------------------------------------------------------------------------------------
+                                          QUERY PLAN                                           
+-----------------------------------------------------------------------------------------------
  Foreign Scan
    Output: (count(c3))
    Relations: Aggregate on (public.ft1 t1)
-   Remote SQL: SELECT count(r1.c3) FROM "S 1"."T 1" r1 WHERE (("C 1" = public.postgres_fdw_abs(c2)))
+   Remote SQL: SELECT count(c3) FROM "S 1"."T 1" WHERE (("C 1" = public.postgres_fdw_abs(c2)))
 (4 rows)
 
 SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = postgres_fdw_abs(t1.c2);
@@ -951,12 +951,12 @@ SELECT count(c3) FROM ft1 t1 WHERE t1.c1 = postgres_fdw_abs(t1.c2);
 
 EXPLAIN (VERBOSE, COSTS OFF)
   SELECT count(c3) FROM ft1 t1 WHERE t1.c1 === t1.c2;
-                                          QUERY PLAN                                           
------------------------------------------------------------------------------------------------
+                                       QUERY PLAN                                        
+-----------------------------------------------------------------------------------------
  Foreign Scan
    Output: (count(c3))
    Relations: Aggregate on (public.ft1 t1)
-   Remote SQL: SELECT count(r1.c3) FROM "S 1"."T 1" r1 WHERE (("C 1" OPERATOR(public.===) c2))
+   Remote SQL: SELECT count(c3) FROM "S 1"."T 1" WHERE (("C 1" OPERATOR(public.===) c2))
 (4 rows)
 
 SELECT count(c3) FROM ft1 t1 WHERE t1.c1 === t1.c2;
@@ -4437,12 +4437,12 @@ SELECT * FROM ft1 ORDER BY c6 ASC NULLS FIRST, c1 OFFSET 15 LIMIT 10;
 -- Consistent check constraints provide consistent results
 ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c2positive CHECK (c2 >= 0);
 EXPLAIN (VERBOSE, COSTS OFF) SELECT count(*) FROM ft1 WHERE c2 < 0;
-                             QUERY PLAN                             
---------------------------------------------------------------------
+                           QUERY PLAN                            
+-----------------------------------------------------------------
  Foreign Scan
    Output: (count(*))
    Relations: Aggregate on (public.ft1)
-   Remote SQL: SELECT count(*) FROM "S 1"."T 1" r1 WHERE ((c2 < 0))
+   Remote SQL: SELECT count(*) FROM "S 1"."T 1" WHERE ((c2 < 0))
 (4 rows)
 
 SELECT count(*) FROM ft1 WHERE c2 < 0;
@@ -4481,12 +4481,12 @@ ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c2positive;
 -- But inconsistent check constraints provide inconsistent results
 ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c2negative CHECK (c2 < 0);
 EXPLAIN (VERBOSE, COSTS OFF) SELECT count(*) FROM ft1 WHERE c2 >= 0;
-                             QUERY PLAN                              
----------------------------------------------------------------------
+                            QUERY PLAN                            
+------------------------------------------------------------------
  Foreign Scan
    Output: (count(*))
    Relations: Aggregate on (public.ft1)
-   Remote SQL: SELECT count(*) FROM "S 1"."T 1" r1 WHERE ((c2 >= 0))
+   Remote SQL: SELECT count(*) FROM "S 1"."T 1" WHERE ((c2 >= 0))
 (4 rows)
 
 SELECT count(*) FROM ft1 WHERE c2 >= 0;
@@ -5883,12 +5883,12 @@ ROLLBACK;
 -- A. Simple aggregates
 explain (verbose, costs off)
 select sum(c1), avg(c1), min(c2), max(c1), stddev(c2) from ft1;
-                                                   QUERY PLAN                                                    
------------------------------------------------------------------------------------------------------------------
+                                          QUERY PLAN                                           
+-----------------------------------------------------------------------------------------------
  Foreign Scan
    Output: (sum(c1)), (avg(c1)), (min(c2)), (max(c1)), (stddev(c2))
    Relations: Aggregate on (public.ft1)
-   Remote SQL: SELECT sum(r1."C 1"), avg(r1."C 1"), min(r1.c2), max(r1."C 1"), stddev(r1.c2) FROM "S 1"."T 1" r1
+   Remote SQL: SELECT sum("C 1"), avg("C 1"), min(c2), max("C 1"), stddev(c2) FROM "S 1"."T 1"
 (4 rows)
 
 select sum(c1), avg(c1), min(c2), max(c1), stddev(c2) from ft1;
@@ -5905,22 +5905,22 @@ select sum("C 1"), avg("C 1"), min(c2), max("C 1"), stddev(c2) from "S 1"."T 1";
 
 explain (verbose, costs off)
 select sum(c1) * random() from ft1;
-                       QUERY PLAN                       
---------------------------------------------------------
+                      QUERY PLAN                      
+------------------------------------------------------
  Foreign Scan
    Output: (((sum(c1)))::double precision * random())
    Relations: Aggregate on (public.ft1)
-   Remote SQL: SELECT sum(r1."C 1") FROM "S 1"."T 1" r1
+   Remote SQL: SELECT sum("C 1") FROM "S 1"."T 1"
 (4 rows)
 
 explain (verbose, costs off)
 select count(c6) from ft1;
-                      QUERY PLAN                       
--------------------------------------------------------
+                   QUERY PLAN                    
+-------------------------------------------------
  Foreign Scan
    Output: (count(c6))
    Relations: Aggregate on (public.ft1)
-   Remote SQL: SELECT count(r1.c6) FROM "S 1"."T 1" r1
+   Remote SQL: SELECT count(c6) FROM "S 1"."T 1"
 (4 rows)
 
 select count(c6) from ft1;
@@ -5949,12 +5949,12 @@ select sum(c1 * random()), avg(c1) from ft1;
 
 explain (verbose, costs off)
 select sum(c1) from ft2 where c2 < 5;
-                               QUERY PLAN                                
--------------------------------------------------------------------------
+                            QUERY PLAN                             
+-------------------------------------------------------------------
  Foreign Scan
    Output: (sum(c1))
    Relations: Aggregate on (public.ft2)
-   Remote SQL: SELECT sum(r1."C 1") FROM "S 1"."T 1" r1 WHERE ((c2 < 5))
+   Remote SQL: SELECT sum("C 1") FROM "S 1"."T 1" WHERE ((c2 < 5))
 (4 rows)
 
 select sum(c1) from ft2 where c2 < 5;
@@ -6035,15 +6035,15 @@ select count(*) from ft1 t1 inner join ft1 t2 on (t1.c2 = t2.c2 * random());
 -- B. Aggregates with GROUP BY
 explain (verbose, costs off)
 select c2, count(*) from ft1 group by c2 order by 1;
-                                  QUERY PLAN                                   
--------------------------------------------------------------------------------
+                              QUERY PLAN                              
+----------------------------------------------------------------------
  Sort
    Output: c2, (count(*))
    Sort Key: ft1.c2
    ->  Foreign Scan
          Output: c2, (count(*))
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT r1.c2, count(*) FROM "S 1"."T 1" r1 GROUP BY r1.c2
+         Remote SQL: SELECT c2, count(*) FROM "S 1"."T 1" GROUP BY c2
 (7 rows)
 
 select c2, count(*) from ft1 group by c2 order by 1;
@@ -6100,15 +6100,15 @@ select c2, count(*) from "S 1"."T 1" group by c2 order by 1;
 
 explain (verbose, costs off)
 select count(c1), length(c6) from ft2 group by c6 order by 1, 2;
-                                             QUERY PLAN                                              
------------------------------------------------------------------------------------------------------
+                                      QUERY PLAN                                      
+--------------------------------------------------------------------------------------
  Sort
    Output: (count(c1)), (length((c6)::text)), c6
    Sort Key: (count(ft2.c1)), (length((ft2.c6)::text))
    ->  Foreign Scan
          Output: (count(c1)), (length((c6)::text)), c6
          Relations: Aggregate on (public.ft2)
-         Remote SQL: SELECT count(r1."C 1"), length(r1.c6), r1.c6 FROM "S 1"."T 1" r1 GROUP BY r1.c6
+         Remote SQL: SELECT count("C 1"), length(c6), c6 FROM "S 1"."T 1" GROUP BY c6
 (7 rows)
 
 select count(c1), length(c6) from ft2 group by c6 order by 1, 2;
@@ -6143,15 +6143,15 @@ select count("C 1"), length(c6) from "S 1"."T 1" group by c6 order by 1, 2;
 
 explain (verbose, costs off)
 select c2/2, sum(c2) * (c2/2) from ft1 group by c2/2 order by c2/2;
-                                                  QUERY PLAN                                                   
----------------------------------------------------------------------------------------------------------------
+                                           QUERY PLAN                                           
+------------------------------------------------------------------------------------------------
  Sort
    Output: ((c2 / 2)), ((sum(c2) * (c2 / 2)))
    Sort Key: ((ft1.c2 / 2))
    ->  Foreign Scan
          Output: ((c2 / 2)), ((sum(c2) * (c2 / 2)))
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT (r1.c2 / 2), (sum(r1.c2) * (r1.c2 / 2)) FROM "S 1"."T 1" r1 GROUP BY ((r1.c2 / 2))
+         Remote SQL: SELECT (c2 / 2), (sum(c2) * (c2 / 2)) FROM "S 1"."T 1" GROUP BY ((c2 / 2))
 (7 rows)
 
 select c2/2, sum(c2) * (c2/2) from ft1 group by c2/2 order by c2/2;
@@ -6204,8 +6204,8 @@ select c2/2, sum(c2) * (c2/2) from "S 1"."T 1" group by c2/2 order by c2/2;
 
 explain (verbose, costs off)
 select count(a), sum(a) from (select c2 a, sum(c1) b from ft1 group by c2, sqrt(c1) order by 1, 2) x;
-                                                         QUERY PLAN                                                         
-----------------------------------------------------------------------------------------------------------------------------
+                                                QUERY PLAN                                                
+----------------------------------------------------------------------------------------------------------
  Aggregate
    Output: count(ft1.c2), sum(ft1.c2)
    ->  Sort
@@ -6214,7 +6214,7 @@ select count(a), sum(a) from (select c2 a, sum(c1) b from ft1 group by c2, sqrt(
          ->  Foreign Scan
                Output: ft1.c2, (sum(ft1.c1)), (sqrt((ft1.c1)::double precision))
                Relations: Aggregate on (public.ft1)
-               Remote SQL: SELECT r1.c2, sum(r1."C 1"), sqrt(r1."C 1") FROM "S 1"."T 1" r1 GROUP BY r1.c2, (sqrt(r1."C 1"))
+               Remote SQL: SELECT c2, sum("C 1"), sqrt("C 1") FROM "S 1"."T 1" GROUP BY c2, (sqrt("C 1"))
 (9 rows)
 
 select count(a), sum(a) from (select c2 a, sum(c1) b from ft1 group by c2, sqrt(c1) order by 1, 2) x;
@@ -6232,12 +6232,12 @@ select count(a), sum(a) from (select c2 a, sum("C 1") b from "S 1"."T 1" group b
 -- Aggregate is still pushed down by taking random() out
 explain (verbose, costs off)
 select c1 * random(), sum(c1) * c1 from ft1 group by c1;
-                                           QUERY PLAN                                            
--------------------------------------------------------------------------------------------------
+                                    QUERY PLAN                                    
+----------------------------------------------------------------------------------
  Foreign Scan
    Output: ((c1)::double precision * random()), ((sum(c1) * c1)), c1
    Relations: Aggregate on (public.ft1)
-   Remote SQL: SELECT (sum(r1."C 1") * r1."C 1"), r1."C 1" FROM "S 1"."T 1" r1 GROUP BY r1."C 1"
+   Remote SQL: SELECT (sum("C 1") * "C 1"), "C 1" FROM "S 1"."T 1" GROUP BY "C 1"
 (4 rows)
 
 --select c1 * random(), sum(c1) * c1 from ft1 group by c1;
@@ -6258,15 +6258,15 @@ select c1 * random() from ft2 group by c1 * random(), c2;
 -- C. Aggregates with HAVING clause
 explain (verbose, costs off)
 select c2, sum(c1) from ft2 group by c2 having avg(c1) < 500 order by 1;
-                                                         QUERY PLAN                                                         
-----------------------------------------------------------------------------------------------------------------------------
+                                                 QUERY PLAN                                                  
+-------------------------------------------------------------------------------------------------------------
  Sort
    Output: c2, (sum(c1))
    Sort Key: ft2.c2
    ->  Foreign Scan
          Output: c2, (sum(c1))
          Relations: Aggregate on (public.ft2)
-         Remote SQL: SELECT r1.c2, sum(r1."C 1") FROM "S 1"."T 1" r1 GROUP BY r1.c2 HAVING ((avg(r1."C 1") < 500::numeric))
+         Remote SQL: SELECT c2, sum("C 1") FROM "S 1"."T 1" GROUP BY c2 HAVING ((avg("C 1") < 500::numeric))
 (7 rows)
 
 select c2, sum(c1) from ft2 group by c2 having avg(c1) < 500 order by 1;
@@ -6285,15 +6285,15 @@ select c2, sum("C 1") from "S 1"."T 1" group by c2 having avg("C 1") < 500 order
 
 explain (verbose, costs off)
 select c2, sum(c1) from ft1 group by c2 having avg(c1) < 500 and sum(c1) < 200000 order by c2;
-                                                                        QUERY PLAN                                                                         
------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                               QUERY PLAN                                                                
+-----------------------------------------------------------------------------------------------------------------------------------------
  Sort
    Output: c2, (sum(c1))
    Sort Key: ft1.c2
    ->  Foreign Scan
          Output: c2, (sum(c1))
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT r1.c2, sum(r1."C 1") FROM "S 1"."T 1" r1 GROUP BY r1.c2 HAVING ((avg(r1."C 1") < 500::numeric)) AND ((sum(r1."C 1") < 200000))
+         Remote SQL: SELECT c2, sum("C 1") FROM "S 1"."T 1" GROUP BY c2 HAVING ((avg("C 1") < 500::numeric)) AND ((sum("C 1") < 200000))
 (7 rows)
 
 select c2, sum(c1) from ft1 group by c2 having avg(c1) < 500 and sum(c1) < 200000 order by c2;
@@ -6312,15 +6312,15 @@ select c2, sum("C 1") from "S 1"."T 1" group by c2 having avg("C 1") < 500 and s
 
 explain (verbose, costs off)
 select c5, count(c2) from ft1 group by c5, sqrt(c2) having sqrt(max(c2)) < 2 order by 1, 2;
-                                                                           QUERY PLAN                                                                            
------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                 QUERY PLAN                                                                 
+--------------------------------------------------------------------------------------------------------------------------------------------
  Sort
    Output: c5, (count(c2)), (sqrt((c2)::double precision))
    Sort Key: ft1.c5, (count(ft1.c2))
    ->  Foreign Scan
          Output: c5, (count(c2)), (sqrt((c2)::double precision))
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT r1.c5, count(r1.c2), sqrt(r1.c2) FROM "S 1"."T 1" r1 GROUP BY r1.c5, (sqrt(r1.c2)) HAVING ((sqrt(max(r1.c2)) < 2::double precision))
+         Remote SQL: SELECT c5, count(c2), sqrt(c2) FROM "S 1"."T 1" GROUP BY c5, (sqrt(c2)) HAVING ((sqrt(max(c2)) < 2::double precision))
 (7 rows)
 
 select c5, count(c2) from ft1 group by c5, sqrt(c2) having sqrt(max(c2)) < 2 order by 1, 2;
@@ -6369,7 +6369,7 @@ select c2, sum(c1) from ft2 group by c2 having sum(c1) * random() < 500000 order
          Output: c2, (sum(c1))
          Filter: ((((sum(ft2.c1)))::double precision * random()) < '500000'::double precision)
          Relations: Aggregate on (public.ft2)
-         Remote SQL: SELECT r1.c2, sum(r1."C 1") FROM "S 1"."T 1" r1 GROUP BY r1.c2
+         Remote SQL: SELECT c2, sum("C 1") FROM "S 1"."T 1" GROUP BY c2
 (8 rows)
 
 select c2, sum(c1) from ft2 group by c2 having sum(c1) * random() < 500000 order by c2;
@@ -6427,15 +6427,15 @@ select c2, sum("C 1") from "S 1"."T 1" group by c2 having sum("C 1") * random()
 -- Having clause with random() will be evaluated locally, and other having qual is pushed
 explain (verbose, costs off)
 select count(*) from (select c5, count(c1) from ft1 group by c5, sqrt(c2) having avg(c1) * random() < 500 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)))::double precision * random()) < '500'::double precision)
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT r1.c5, NULL::bigint, sqrt(r1.c2), avg(r1."C 1") FROM "S 1"."T 1" r1 GROUP BY r1.c5, (sqrt(r1.c2)) HAVING ((avg(r1."C 1") < 500::numeric))
+         Remote SQL: SELECT c5, NULL::bigint, sqrt(c2), avg("C 1") FROM "S 1"."T 1" GROUP BY c5, (sqrt(c2)) HAVING ((avg("C 1") < 500::numeric))
 (7 rows)
 
 select count(*) from (select c5, count(c1) from ft1 group by c5, sqrt(c2) having avg(c1) * random() < 500 and avg(c1) < 500) x;
@@ -6453,12 +6453,12 @@ select count(*) from (select c5, count("C 1") from "S 1"."T 1" group by c5, sqrt
 -- D. ORDER BY, DISTINCT, FILTER, Ordered-sets and VARIADIC within aggregates
 explain (verbose, costs off)
 select array_agg(c1 order by c3) from ft1 where c2 = 6 and c1 < 100;
-                                                    QUERY PLAN                                                    
-------------------------------------------------------------------------------------------------------------------
+                                               QUERY PLAN                                                
+---------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: (array_agg(c1 ORDER BY c3))
    Relations: Aggregate on (public.ft1)
-   Remote SQL: SELECT array_agg(r1."C 1" ORDER BY r1.c3) FROM "S 1"."T 1" r1 WHERE (("C 1" < 100)) AND ((c2 = 6))
+   Remote SQL: SELECT array_agg("C 1" ORDER BY c3) FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND ((c2 = 6))
 (4 rows)
 
 select array_agg(c1 order by c3) from ft1 where c2 = 6 and c1 < 100;
@@ -6475,15 +6475,15 @@ select array_agg("C 1" order by c3) from "S 1"."T 1" where c2 = 6 and "C 1" < 10
 
 explain (verbose, costs off)
 select array_agg(c1 order by c1) from ft2 where c1 < 100 group by c2 order by 1;
-                                                            QUERY PLAN                                                            
-----------------------------------------------------------------------------------------------------------------------------------
+                                                    QUERY PLAN                                                     
+-------------------------------------------------------------------------------------------------------------------
  Sort
    Output: (array_agg(c1 ORDER BY c1)), c2
    Sort Key: (array_agg(ft2.c1 ORDER BY ft2.c1))
    ->  Foreign Scan
          Output: (array_agg(c1 ORDER BY c1)), c2
          Relations: Aggregate on (public.ft2)
-         Remote SQL: SELECT array_agg(r1."C 1" ORDER BY r1."C 1"), r1.c2 FROM "S 1"."T 1" r1 WHERE (("C 1" < 100)) GROUP BY r1.c2
+         Remote SQL: SELECT array_agg("C 1" ORDER BY "C 1"), c2 FROM "S 1"."T 1" WHERE (("C 1" < 100)) GROUP BY c2
 (7 rows)
 
 select array_agg(c1 order by c1) from ft2 where c1 < 100 group by c2 order by 1;
@@ -6516,12 +6516,12 @@ select array_agg("C 1" order by "C 1") from "S 1"."T 1" where "C 1" < 100 group
 
 explain (verbose, costs off)
 select array_agg(c1 order by c1 desc) from ft1 where c2 = 6 and c1 < 100 group by c2;
-                                                                   QUERY PLAN                                                                   
-------------------------------------------------------------------------------------------------------------------------------------------------
+                                                           QUERY PLAN                                                            
+---------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: (array_agg(c1 ORDER BY c1 DESC)), c2
    Relations: Aggregate on (public.ft1)
-   Remote SQL: SELECT array_agg(r1."C 1" ORDER BY r1."C 1" DESC), r1.c2 FROM "S 1"."T 1" r1 WHERE (("C 1" < 100)) AND ((c2 = 6)) GROUP BY r1.c2
+   Remote SQL: SELECT array_agg("C 1" ORDER BY "C 1" DESC), c2 FROM "S 1"."T 1" WHERE (("C 1" < 100)) AND ((c2 = 6)) GROUP BY c2
 (4 rows)
 
 select array_agg(c1 order by c1 desc) from ft1 where c2 = 6 and c1 < 100 group by c2;
@@ -6538,12 +6538,12 @@ select array_agg("C 1" order by "C 1" desc) from "S 1"."T 1" where c2 = 6 and "C
 
 explain (verbose, costs off)
 select array_agg(c5 order by c1 desc) from ft2 where c2 = 6 and c1 < 50;
-                                                      QUERY PLAN                                                      
-----------------------------------------------------------------------------------------------------------------------
+                                                 QUERY PLAN                                                  
+-------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: (array_agg(c5 ORDER BY c1 DESC))
    Relations: Aggregate on (public.ft2)
-   Remote SQL: SELECT array_agg(r1.c5 ORDER BY r1."C 1" DESC) FROM "S 1"."T 1" r1 WHERE (("C 1" < 50)) AND ((c2 = 6))
+   Remote SQL: SELECT array_agg(c5 ORDER BY "C 1" DESC) FROM "S 1"."T 1" WHERE (("C 1" < 50)) AND ((c2 = 6))
 (4 rows)
 
 select array_agg(c5 order by c1 desc) from ft2 where c2 = 6 and c1 < 50;
@@ -6668,12 +6668,12 @@ select array_agg(distinct (t1.c1)%5 order by (t1.c1)%5 desc nulls last) from "S
 
 explain (verbose, costs off)
 select sum(c1%3), sum(distinct c1%3) filter (where c1%3 < 2), c2 from ft1 where c2 = 6 group by c2;
-                                                                              QUERY PLAN                                                                               
------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                     QUERY PLAN                                                                      
+-----------------------------------------------------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: (sum((c1 % 3))), (sum(DISTINCT (c1 % 3)) FILTER (WHERE ((c1 % 3) < 2))), c2
    Relations: Aggregate on (public.ft1)
-   Remote SQL: SELECT sum((r1."C 1" % 3)), sum(DISTINCT (r1."C 1" % 3)) FILTER (WHERE ((r1."C 1" % 3) < 2)), r1.c2 FROM "S 1"."T 1" r1 WHERE ((c2 = 6)) GROUP BY r1.c2
+   Remote SQL: SELECT sum(("C 1" % 3)), sum(DISTINCT ("C 1" % 3)) FILTER (WHERE (("C 1" % 3) < 2)), c2 FROM "S 1"."T 1" WHERE ((c2 = 6)) GROUP BY c2
 (4 rows)
 
 select sum(c1%3), sum(distinct c1%3) filter (where c1%3 < 2), c2 from ft1 where c2 = 6 group by c2;
@@ -6691,8 +6691,8 @@ select sum("C 1"%3), sum(distinct "C 1"%3) filter (where "C 1"%3 < 2), c2 from "
 -- DISTINCT itself is not pushed down, whereas underneath aggregate is pushed
 explain (verbose, costs off)
 select distinct sum(c1), c2 from ft2 where c2 < 6 group by c2 order by c2;
-                                                QUERY PLAN                                                 
------------------------------------------------------------------------------------------------------------
+                                          QUERY PLAN                                           
+-----------------------------------------------------------------------------------------------
  Unique
    Output: (sum(c1)), c2
    ->  Sort
@@ -6701,7 +6701,7 @@ select distinct sum(c1), c2 from ft2 where c2 < 6 group by c2 order by c2;
          ->  Foreign Scan
                Output: (sum(c1)), c2
                Relations: Aggregate on (public.ft2)
-               Remote SQL: SELECT sum(r1."C 1"), r1.c2 FROM "S 1"."T 1" r1 WHERE ((c2 < 6)) GROUP BY r1.c2
+               Remote SQL: SELECT sum("C 1"), c2 FROM "S 1"."T 1" WHERE ((c2 < 6)) GROUP BY c2
 (9 rows)
 
 select distinct sum(c1), c2 from ft2 where c2 < 6 group by c2 order by c2;
@@ -6720,15 +6720,15 @@ select distinct sum("C 1"), c2 from "S 1"."T 1" where c2 < 6 group by c2 order b
 
 explain (verbose, costs off)
 select sum(c1) filter (where c1 < 100) from ft1 group by c2 order by 1 nulls last;
-                                                     QUERY PLAN                                                     
---------------------------------------------------------------------------------------------------------------------
+                                             QUERY PLAN                                              
+-----------------------------------------------------------------------------------------------------
  Sort
    Output: (sum(c1) FILTER (WHERE (c1 < 100))), c2
    Sort Key: (sum(ft1.c1) FILTER (WHERE (ft1.c1 < 100)))
    ->  Foreign Scan
          Output: (sum(c1) FILTER (WHERE (c1 < 100))), c2
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT sum(r1."C 1") FILTER (WHERE (r1."C 1" < 100)), r1.c2 FROM "S 1"."T 1" r1 GROUP BY r1.c2
+         Remote SQL: SELECT sum("C 1") FILTER (WHERE ("C 1" < 100)), c2 FROM "S 1"."T 1" GROUP BY c2
 (7 rows)
 
 select sum(c1) filter (where c1 < 100) from ft1 group by c2 order by 1 nulls last;
@@ -6785,15 +6785,15 @@ select sum("C 1") filter (where "C 1" < 100) from "S 1"."T 1" group by c2 order
 
 explain (verbose, costs off)
 select sum(c1) filter (where c1 < 100 and c2 > 5) from ft1 group by c2 order by 1 nulls last;
-                                                              QUERY PLAN                                                              
---------------------------------------------------------------------------------------------------------------------------------------
+                                                     QUERY PLAN                                                     
+--------------------------------------------------------------------------------------------------------------------
  Sort
    Output: (sum(c1) FILTER (WHERE ((c1 < 100) AND (c2 > 5)))), c2
    Sort Key: (sum(ft1.c1) FILTER (WHERE ((ft1.c1 < 100) AND (ft1.c2 > 5))))
    ->  Foreign Scan
          Output: (sum(c1) FILTER (WHERE ((c1 < 100) AND (c2 > 5)))), c2
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT sum(r1."C 1") FILTER (WHERE ((r1."C 1" < 100) AND (r1.c2 > 5))), r1.c2 FROM "S 1"."T 1" r1 GROUP BY r1.c2
+         Remote SQL: SELECT sum("C 1") FILTER (WHERE (("C 1" < 100) AND (c2 > 5))), c2 FROM "S 1"."T 1" GROUP BY c2
 (7 rows)
 
 select sum(c1) filter (where c1 < 100 and c2 > 5) from ft1 group by c2 order by 1 nulls last;
@@ -6851,8 +6851,8 @@ select sum("C 1") filter (where "C 1" < 100 and c2 > 5) from "S 1"."T 1" group b
 -- Outer query is aggregation query
 explain (verbose, costs off)
 select distinct (select count(*) filter (where t2.c2 = 6 and t2.c1 < 10) from ft1 t1 where t1.c1 = 6) from ft1 t2 order by 1;
-                                                   QUERY PLAN                                                   
-----------------------------------------------------------------------------------------------------------------
+                                              QUERY PLAN                                               
+-------------------------------------------------------------------------------------------------------
  Unique
    Output: ((SubPlan 1))
    ->  Sort
@@ -6861,7 +6861,7 @@ select distinct (select count(*) filter (where t2.c2 = 6 and t2.c1 < 10) from ft
          ->  Foreign Scan
                Output: (SubPlan 1)
                Relations: Aggregate on (public.ft1 t2)
-               Remote SQL: SELECT count(*) FILTER (WHERE ((r1.c2 = 6) AND (r1."C 1" < 10))) FROM "S 1"."T 1" r1
+               Remote SQL: SELECT count(*) FILTER (WHERE ((c2 = 6) AND ("C 1" < 10))) FROM "S 1"."T 1"
                SubPlan 1
                  ->  Foreign Scan on public.ft1 t1
                        Output: (count(*) FILTER (WHERE ((t2.c2 = 6) AND (t2.c1 < 10))))
@@ -6883,8 +6883,8 @@ select distinct (select count(*) filter (where t2.c2 = 6 and t2."C 1" < 10) from
 -- Inner query is aggregation query
 explain (verbose, costs off)
 select distinct (select count(t1.c1) filter (where t2.c2 = 6 and t2.c1 < 10) from ft1 t1 where t1.c1 = 6) from ft1 t2 order by 1;
-                                                                         QUERY PLAN                                                                         
-------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                      QUERY PLAN                                                                      
+------------------------------------------------------------------------------------------------------------------------------------------------------
  Unique
    Output: ((SubPlan 1))
    ->  Sort
@@ -6897,7 +6897,7 @@ select distinct (select count(t1.c1) filter (where t2.c2 = 6 and t2.c1 < 10) fro
                  ->  Foreign Scan
                        Output: (count(t1.c1) FILTER (WHERE ((t2.c2 = 6) AND (t2.c1 < 10))))
                        Relations: Aggregate on (public.ft1 t1)
-                       Remote SQL: SELECT count(r1."C 1") FILTER (WHERE (($1::integer = 6) AND ($2::integer < 10))) FROM "S 1"."T 1" r1 WHERE (("C 1" = 6))
+                       Remote SQL: SELECT count("C 1") FILTER (WHERE (($1::integer = 6) AND ($2::integer < 10))) FROM "S 1"."T 1" WHERE (("C 1" = 6))
 (13 rows)
 
 select distinct (select count(t1.c1) filter (where t2.c2 = 6 and t2.c1 < 10) from ft1 t1 where t1.c1 = 6) from ft1 t2 order by 1;
@@ -6944,12 +6944,12 @@ select sum(c2) filter (where c2 in (select c2 from ft1 where c2 < 5)) from ft1;
 
 explain (verbose, costs off)
 select percentile_disc(0.25) within group (order by c2) from ft1;
-                                                   QUERY PLAN                                                   
-----------------------------------------------------------------------------------------------------------------
+                                                QUERY PLAN                                                
+----------------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: (percentile_disc('0.25'::double precision) WITHIN GROUP (ORDER BY c2))
    Relations: Aggregate on (public.ft1)
-   Remote SQL: SELECT percentile_disc(0.25::double precision) WITHIN GROUP (ORDER BY r1.c2) FROM "S 1"."T 1" r1
+   Remote SQL: SELECT percentile_disc(0.25::double precision) WITHIN GROUP (ORDER BY c2) FROM "S 1"."T 1"
 (4 rows)
 
 select percentile_disc(0.25) within group (order by c2) from ft1;
@@ -6966,15 +6966,15 @@ select percentile_disc(0.25) within group (order by c2) from "S 1"."T 1";
 
 explain (verbose, costs off)
 select c2, percentile_cont(0.5) within group (order by c1) from ft1 where c2 < 10 group by c2 order by 1;
-                                                                            QUERY PLAN                                                                            
-------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                      QUERY PLAN                                                                      
+------------------------------------------------------------------------------------------------------------------------------------------------------
  Sort
    Output: c2, (percentile_cont('0.5'::double precision) WITHIN GROUP (ORDER BY ((c1)::double precision)))
    Sort Key: ft1.c2
    ->  Foreign Scan
          Output: c2, (percentile_cont('0.5'::double precision) WITHIN GROUP (ORDER BY ((c1)::double precision)))
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT r1.c2, percentile_cont(0.5::double precision) WITHIN GROUP (ORDER BY (r1."C 1")) FROM "S 1"."T 1" r1 WHERE ((c2 < 10)) GROUP BY r1.c2
+         Remote SQL: SELECT c2, percentile_cont(0.5::double precision) WITHIN GROUP (ORDER BY ("C 1")) FROM "S 1"."T 1" WHERE ((c2 < 10)) GROUP BY c2
 (7 rows)
 
 select c2, percentile_cont(0.5) within group (order by c1) from ft1 where c2 < 10 group by c2 order by 1;
@@ -6996,33 +6996,33 @@ select c2, percentile_cont(0.5) within group (order by "C 1") from "S 1"."T 1" w
 -- Error from remote server
 explain (verbose, costs off)
 select c2, percentile_cont(c2) within group (order by c1) from ft1 group by c2 order by c2;
-                                                           QUERY PLAN                                                           
---------------------------------------------------------------------------------------------------------------------------------
+                                                   QUERY PLAN                                                    
+-----------------------------------------------------------------------------------------------------------------
  Sort
    Output: c2, (percentile_cont((c2)::double precision) WITHIN GROUP (ORDER BY ((c1)::double precision)))
    Sort Key: ft1.c2
    ->  Foreign Scan
          Output: c2, (percentile_cont((c2)::double precision) WITHIN GROUP (ORDER BY ((c1)::double precision)))
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT r1.c2, percentile_cont(r1.c2) WITHIN GROUP (ORDER BY (r1."C 1")) FROM "S 1"."T 1" r1 GROUP BY r1.c2
+         Remote SQL: SELECT c2, percentile_cont(c2) WITHIN GROUP (ORDER BY ("C 1")) FROM "S 1"."T 1" GROUP BY c2
 (7 rows)
 
 select c2, percentile_cont(c2) within group (order by c1) from ft1 group by c2 order by c2;
 ERROR:  percentile value 2 is not between 0 and 1
-CONTEXT:  Remote SQL command: SELECT r1.c2, percentile_cont(r1.c2) WITHIN GROUP (ORDER BY (r1."C 1")) FROM "S 1"."T 1" r1 GROUP BY r1.c2
+CONTEXT:  Remote SQL command: SELECT c2, percentile_cont(c2) WITHIN GROUP (ORDER BY ("C 1")) FROM "S 1"."T 1" GROUP BY c2
 select c2, percentile_cont(c2) within group (order by "C 1") from "S 1"."T 1" group by c2 order by c2;
 ERROR:  percentile value 2 is not between 0 and 1
 explain (verbose, costs off)
 select c2, percentile_cont(c2/10::numeric) within group (order by c1) from ft1 where c2 < 10 group by c2 having percentile_cont(c2/10::numeric) within group (order by c1) < 500 order by c2;
-                                                                                                                                  QUERY PLAN                                                                                                                                   
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                        QUERY PLAN                                                                                                                        
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Sort
    Output: c2, (percentile_cont((((c2)::numeric / '10'::numeric))::double precision) WITHIN GROUP (ORDER BY ((c1)::double precision)))
    Sort Key: ft1.c2
    ->  Foreign Scan
          Output: c2, (percentile_cont((((c2)::numeric / '10'::numeric))::double precision) WITHIN GROUP (ORDER BY ((c1)::double precision)))
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT r1.c2, percentile_cont((r1.c2 / 10::numeric)) WITHIN GROUP (ORDER BY (r1."C 1")) FROM "S 1"."T 1" r1 WHERE ((c2 < 10)) GROUP BY r1.c2 HAVING ((percentile_cont((r1.c2 / 10::numeric)) WITHIN GROUP (ORDER BY (r1."C 1")) < 500::double precision))
+         Remote SQL: SELECT c2, percentile_cont((c2 / 10::numeric)) WITHIN GROUP (ORDER BY ("C 1")) FROM "S 1"."T 1" WHERE ((c2 < 10)) GROUP BY c2 HAVING ((percentile_cont((c2 / 10::numeric)) WITHIN GROUP (ORDER BY ("C 1")) < 500::double precision))
 (7 rows)
 
 select c2, percentile_cont(c2/10::numeric) within group (order by c1) from ft1 where c2 < 10 group by c2 having percentile_cont(c2/10::numeric) within group (order by c1) < 500 order by c2;
@@ -7041,12 +7041,12 @@ select c2, percentile_cont(c2/10::numeric) within group (order by "C 1") from "S
 
 explain (verbose, costs off)
 select rank('10'::varchar) within group (order by c6) from ft1;
-                                              QUERY PLAN                                              
-------------------------------------------------------------------------------------------------------
+                                           QUERY PLAN                                           
+------------------------------------------------------------------------------------------------
  Foreign Scan
    Output: (rank('10'::character varying) WITHIN GROUP (ORDER BY c6))
    Relations: Aggregate on (public.ft1)
-   Remote SQL: SELECT rank('10'::character varying) WITHIN GROUP (ORDER BY r1.c6) FROM "S 1"."T 1" r1
+   Remote SQL: SELECT rank('10'::character varying) WITHIN GROUP (ORDER BY c6) FROM "S 1"."T 1"
 (4 rows)
 
 select rank('10'::varchar) within group (order by c6) from ft1;
@@ -7091,15 +7091,15 @@ ALTER SERVER loopback OPTIONS (SET extensions 'postgres_fdw');
 -- Now aggregate with VARIADIC will be pushed
 explain (verbose, costs off)
 select c2, least_agg(c1) from ft1 where c2 < 100 group by c2 order by c2;
-                                                             QUERY PLAN                                                             
-------------------------------------------------------------------------------------------------------------------------------------
+                                                       QUERY PLAN                                                       
+------------------------------------------------------------------------------------------------------------------------
  Sort
    Output: c2, (least_agg(VARIADIC ARRAY[c1]))
    Sort Key: ft1.c2
    ->  Foreign Scan
          Output: c2, (least_agg(VARIADIC ARRAY[c1]))
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT r1.c2, public.least_agg(VARIADIC ARRAY[r1."C 1"]) FROM "S 1"."T 1" r1 WHERE ((c2 < 100)) GROUP BY r1.c2
+         Remote SQL: SELECT c2, public.least_agg(VARIADIC ARRAY["C 1"]) FROM "S 1"."T 1" WHERE ((c2 < 100)) GROUP BY c2
 (7 rows)
 
 select c2, least_agg(c1) from ft1 where c2 < 100 group by c2 order by c2;
@@ -7126,15 +7126,15 @@ select c2, least_agg("C 1") from "S 1"."T 1" where c2 < 100 group by c2 order by
 -- Clauses with random() will be evaluated locally, and other clauses are pushed
 explain (verbose, costs off)
 select count(*) from (select c2 * random(), count(c1) from ft2 group by c2 having sum(c1) * random() < 100000 and avg(c1) < 50000) x;
-                                                                 QUERY PLAN                                                                 
---------------------------------------------------------------------------------------------------------------------------------------------
+                                                         QUERY PLAN                                                          
+-----------------------------------------------------------------------------------------------------------------------------
  Aggregate
    Output: count(*)
    ->  Foreign Scan
          Output: ((ft2.c2)::double precision * random()), (NULL::bigint), ft2.c2
          Filter: ((((sum(ft2.c1)))::double precision * random()) < '100000'::double precision)
          Relations: Aggregate on (public.ft2)
-         Remote SQL: SELECT NULL::bigint, r1.c2, sum(r1."C 1") FROM "S 1"."T 1" r1 GROUP BY r1.c2 HAVING ((avg(r1."C 1") < 50000::numeric))
+         Remote SQL: SELECT NULL::bigint, c2, sum("C 1") FROM "S 1"."T 1" GROUP BY c2 HAVING ((avg("C 1") < 50000::numeric))
 (7 rows)
 
 select count(*) from (select c2 * random(), count(c1) from ft2 group by c2 having sum(c1) * random() < 100000 and avg(c1) < 50000) x;
@@ -7151,15 +7151,15 @@ select count(*) from (select c2 * random(), count("C 1") from "S 1"."T 1" group
 
 explain (verbose, costs off)
 select c2, sum(c2) from ft1 group by c2 having avg(c2) + c2 < 10 order by c2;
-                                                          QUERY PLAN                                                           
--------------------------------------------------------------------------------------------------------------------------------
+                                                 QUERY PLAN                                                  
+-------------------------------------------------------------------------------------------------------------
  Sort
    Output: c2, (sum(c2))
    Sort Key: ft1.c2
    ->  Foreign Scan
          Output: c2, (sum(c2))
          Relations: Aggregate on (public.ft1)
-         Remote SQL: SELECT r1.c2, sum(r1.c2) FROM "S 1"."T 1" r1 GROUP BY r1.c2 HAVING (((avg(r1.c2) + r1.c2) < 10::numeric))
+         Remote SQL: SELECT c2, sum(c2) FROM "S 1"."T 1" GROUP BY c2 HAVING (((avg(c2) + c2) < 10::numeric))
 (7 rows)
 
 select c2, sum(c2) from ft1 group by c2 having avg(c2) + c2 < 10 order by c2;
@@ -7197,8 +7197,8 @@ select count(t1.c3) from ft1 t1, ft1 t2 where t1.c1 = postgres_fdw_abs(t1.c2);
 -- Subquery in FROM clause having aggregate
 explain (verbose, costs off)
 select count(*), x.b from ft1, (select c2 a, sum(c1) b from ft1 group by c2) x where ft1.c2 = x.a group by x.b order by 1, 2;
-                                                 QUERY PLAN                                                 
-------------------------------------------------------------------------------------------------------------
+                                           QUERY PLAN                                           
+------------------------------------------------------------------------------------------------
  Sort
    Output: (count(*)), x.b
    Sort Key: (count(*)), x.b
@@ -7218,7 +7218,7 @@ select count(*), x.b from ft1, (select c2 a, sum(c1) b from ft1 group by c2) x w
                            ->  Foreign Scan
                                  Output: ft1_1.c2, (sum(ft1_1.c1))
                                  Relations: Aggregate on (public.ft1)
-                                 Remote SQL: SELECT r1.c2, sum(r1."C 1") FROM "S 1"."T 1" r1 GROUP BY r1.c2
+                                 Remote SQL: SELECT c2, sum("C 1") FROM "S 1"."T 1" GROUP BY c2
 (20 rows)
 
 select count(*), x.b from ft1, (select c2 a, sum(c1) b from ft1 group by c2) x where ft1.c2 = x.a group by x.b order by 1, 2;
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index c33916f..4dda273 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -1183,7 +1183,8 @@ postgresGetForeignPlan(PlannerInfo *root,
 			local_exprs = lappend(local_exprs, rinfo->clause);
 	}
 
-	if (foreignrel->reloptkind == RELOPT_JOINREL)
+	if (foreignrel->reloptkind == RELOPT_JOINREL ||
+		foreignrel->reloptkind == RELOPT_UPPER_REL)
 	{
 		/* For a join relation, get the conditions from fdw_private structure */
 		remote_conds = fpinfo->remote_conds;
@@ -1204,6 +1205,13 @@ postgresGetForeignPlan(PlannerInfo *root,
 		{
 			ListCell   *lc;
 
+			/* 
+			 * Right now, we only consider grouping and aggregation beyond
+			 * joins. Queries involving aggregates or grouping do not require
+			 * EPQ mechanism, hence should not have an outer plan here.
+			 */
+			Assert(foreignrel->reloptkind != RELOPT_UPPER_REL);
+
 			outer_plan->targetlist = fdw_scan_tlist;
 
 			foreach(lc, local_exprs)
@@ -1223,17 +1231,6 @@ postgresGetForeignPlan(PlannerInfo *root,
 			}
 		}
 	}
-	else if (foreignrel->reloptkind == RELOPT_UPPER_REL)
-	{
-		/*
-		 * For a grouping relation, get the conditions from fdw_private
-		 * structure.
-		 */
-		remote_conds = fpinfo->remote_conds;
-		local_exprs = fpinfo->local_conds;
-
-		fdw_scan_tlist = build_tlist_to_deparse(root, foreignrel);
-	}
 
 	/*
 	 * Build the query string to be sent for execution, and identify
@@ -2478,7 +2475,7 @@ postgresExplainDirectModify(ForeignScanState *node, ExplainState *es)
  * estimate_path_cost_size
  *		Get cost and size estimates for a foreign scan on given foreign relation
  *		either a base relation or a join between foreign relations or an upper
- *		relation.
+ *		relation containing foreign relations.
  *
  * param_join_conds are the parameterization clauses with outer relations.
  * pathkeys specify the expected sort order if any for given path being costed.
@@ -4443,7 +4440,7 @@ postgresGetForeignJoinPaths(PlannerInfo *root,
 /*
  * Assess whether the aggregation, grouping and having operations can be pushed
  * down to the foreign server.  As a side effect, save information we obtain in
- * this function to PgFdwRelationInfo passed in.
+ * this function to PgFdwRelationInfo of the input relation.
  */
 static bool
 foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel)
@@ -4461,7 +4458,7 @@ foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel)
 	if (query->groupingSets)
 		return false;
 
-	/* Get the fpinfo of the outerrel */
+	/* Get the fpinfo of the underlying scan relation. */
 	ofpinfo = (PgFdwRelationInfo *) fpinfo->outerrel->fdw_private;
 
 	/*
@@ -4474,10 +4471,10 @@ foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel)
 
 	/*
 	 * Evaluate grouping targets and check whether they are safe to push down
-	 * to the remote side.  All GROUP BY expressions will be part of the
-	 * grouping target and thus no need to evaluate it separately.  While doing
-	 * so, add required expressions into target list which can then be used to
-	 * pass to remote server.
+	 * to the foreign side.  All GROUP BY expressions will be part of the
+	 * grouping target and thus there is no need to evaluate it separately. 
+	 * While doing so, add required expressions into target list which
+	 * can then be used to pass to foreign server.
 	 */
 	i = 0;
 	foreach(lc, grouping_target->exprs)
@@ -4490,7 +4487,10 @@ foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel)
 		if (sgref && query->groupClause && query->groupingSets == NIL &&
 			get_sortgroupref_clause_noerr(sgref, query->groupClause) != NULL)
 		{
-			/* Expression matched with GROUP BY, check as is */
+			/*
+			 * If any of the GROUP BY expression is not shippable we can not
+			 * push down aggregation to the foreign server.
+			 */
 			if (!is_foreign_expr(root, grouped_rel, expr, true))
 				return false;
 
@@ -4521,7 +4521,7 @@ foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel)
 
 				/*
 				 * Add aggregates, if any, into tlist.  Plain Var nodes pulled
-				 * are already part of GROUP BY and thus no need to add them
+				 * are already part of some and thus no need to add them
 				 * explicitly.
 				 */
 				foreach(l, aggvars)
@@ -4654,8 +4654,8 @@ postgresGetForeignUpperPaths(PlannerInfo *root, UpperRelationKind stage,
  *
  * Add foreign path for grouping and/or aggregation.
  *
- * input_rel contains the underneath scan rel
- * grouped_rel is the rel for which paths need to be added
+ * input_rel represents the underlying scan. The paths are added to the
+ * grouped_rel.
  */
 static void
 create_foreign_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel,