diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index 8dbf790e89..2e1ec41a54 100644
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -1470,7 +1470,7 @@ create_merge_append_path(PlannerInfo *root,
 					  root,
 					  pathkeys,
 					  subpath->total_cost,
-					  subpath->parent->tuples,
+					  subpath->rows,
 					  subpath->pathtarget->width,
 					  0.0,
 					  work_mem,
diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
index 56a40d50f9..130a924228 100644
--- a/src/test/regress/expected/inherit.out
+++ b/src/test/regress/expected/inherit.out
@@ -1714,6 +1714,29 @@ order by t1.b limit 10;
 (14 rows)
 
 reset enable_nestloop;
+drop table matest0 cascade;
+NOTICE:  drop cascades to table matest1
+-- Test a MergeAppend plan where one child requires a sort
+create table matest0(a int primary key);
+create table matest1() inherits (matest0);
+insert into matest0 select generate_series(1, 400);
+insert into matest1 select generate_series(1, 200);
+analyze matest0;
+analyze matest1;
+explain (costs off)
+select * from matest0 where a < 100 order by a;
+                          QUERY PLAN                           
+---------------------------------------------------------------
+ Merge Append
+   Sort Key: matest0.a
+   ->  Index Only Scan using matest0_pkey on matest0 matest0_1
+         Index Cond: (a < 100)
+   ->  Sort
+         Sort Key: matest0_2.a
+         ->  Seq Scan on matest1 matest0_2
+               Filter: (a < 100)
+(8 rows)
+
 drop table matest0 cascade;
 NOTICE:  drop cascades to table matest1
 --
diff --git a/src/test/regress/sql/inherit.sql b/src/test/regress/sql/inherit.sql
index 971aac54fd..0ef9a61bc1 100644
--- a/src/test/regress/sql/inherit.sql
+++ b/src/test/regress/sql/inherit.sql
@@ -624,6 +624,19 @@ reset enable_nestloop;
 
 drop table matest0 cascade;
 
+-- Test a MergeAppend plan where one child requires a sort
+create table matest0(a int primary key);
+create table matest1() inherits (matest0);
+insert into matest0 select generate_series(1, 400);
+insert into matest1 select generate_series(1, 200);
+analyze matest0;
+analyze matest1;
+
+explain (costs off)
+select * from matest0 where a < 100 order by a;
+
+drop table matest0 cascade;
+
 --
 -- Test merge-append for UNION ALL append relations
 --