1 files changed, 73 insertions, 0 deletions
diff --git a/src/test/regress/expected/union.out b/src/test/regress/expected/union.out
index da70438951d..7189f5bd3d2 100644
--- a/src/test/regress/expected/union.out
+++ b/src/test/regress/expected/union.out
@@ -915,6 +915,79 @@ ORDER BY x;
  2 | 4
 (1 row)
 
+-- Test cases where the native ordering of a sub-select has more pathkeys
+-- than the outer query cares about
+explain (costs off)
+select distinct q1 from
+  (select distinct * from int8_tbl i81
+   union all
+   select distinct * from int8_tbl i82) ss
+where q2 = q2;
+                        QUERY PLAN                        
+----------------------------------------------------------
+ Unique
+   ->  Merge Append
+         Sort Key: "*SELECT* 1".q1
+         ->  Subquery Scan on "*SELECT* 1"
+               ->  Unique
+                     ->  Sort
+                           Sort Key: i81.q1, i81.q2
+                           ->  Seq Scan on int8_tbl i81
+                                 Filter: (q2 IS NOT NULL)
+         ->  Subquery Scan on "*SELECT* 2"
+               ->  Unique
+                     ->  Sort
+                           Sort Key: i82.q1, i82.q2
+                           ->  Seq Scan on int8_tbl i82
+                                 Filter: (q2 IS NOT NULL)
+(15 rows)
+
+select distinct q1 from
+  (select distinct * from int8_tbl i81
+   union all
+   select distinct * from int8_tbl i82) ss
+where q2 = q2;
+        q1        
+------------------
+              123
+ 4567890123456789
+(2 rows)
+
+explain (costs off)
+select distinct q1 from
+  (select distinct * from int8_tbl i81
+   union all
+   select distinct * from int8_tbl i82) ss
+where -q1 = q2;
+                       QUERY PLAN                       
+--------------------------------------------------------
+ Unique
+   ->  Merge Append
+         Sort Key: "*SELECT* 1".q1
+         ->  Subquery Scan on "*SELECT* 1"
+               ->  Unique
+                     ->  Sort
+                           Sort Key: i81.q1, i81.q2
+                           ->  Seq Scan on int8_tbl i81
+                                 Filter: ((- q1) = q2)
+         ->  Subquery Scan on "*SELECT* 2"
+               ->  Unique
+                     ->  Sort
+                           Sort Key: i82.q1, i82.q2
+                           ->  Seq Scan on int8_tbl i82
+                                 Filter: ((- q1) = q2)
+(15 rows)
+
+select distinct q1 from
+  (select distinct * from int8_tbl i81
+   union all
+   select distinct * from int8_tbl i82) ss
+where -q1 = q2;
+        q1        
+------------------
+ 4567890123456789
+(1 row)
+
 -- Test proper handling of parameterized appendrel paths when the
 -- potential join qual is expensive
 create function expensivefunc(int) returns int