Improve regression test for #8410.

The previous version of the query disregarded the result of the MergeAppend
instead of checking its results.

Andres Freund

src/test/regress/expected/inherit.out

@@ -1353,42 +1353,41 @@ ORDER BY x, y;
 -- exercise rescan code path via a repeatedly-evaluated subquery
 explain (costs off)
 SELECT
-    (SELECT g.i FROM (
-        (SELECT * FROM generate_series(1, 2) ORDER BY 1)
+    ARRAY(SELECT f.i FROM (
+        (SELECT d + g.i FROM generate_series(4, 30, 3) d ORDER BY 1)
         UNION ALL
-        (SELECT * FROM generate_series(1, 2) ORDER BY 1)
+        (SELECT d + g.i FROM generate_series(0, 30, 5) d ORDER BY 1)
     ) f(i)
-    ORDER BY f.i LIMIT 1)
+    ORDER BY f.i LIMIT 10)
 FROM generate_series(1, 3) g(i);
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                           QUERY PLAN                           
+----------------------------------------------------------------
  Function Scan on generate_series g
    SubPlan 1
      ->  Limit
-           ->  Result
-                 ->  Merge Append
-                       Sort Key: generate_series.generate_series
-                       ->  Sort
-                             Sort Key: generate_series.generate_series
-                             ->  Function Scan on generate_series
-                       ->  Sort
-                             Sort Key: generate_series_1.generate_series
-                             ->  Function Scan on generate_series generate_series_1
-(12 rows)
+           ->  Merge Append
+                 Sort Key: ((d.d + g.i))
+                 ->  Sort
+                       Sort Key: ((d.d + g.i))
+                       ->  Function Scan on generate_series d
+                 ->  Sort
+                       Sort Key: ((d_1.d + g.i))
+                       ->  Function Scan on generate_series d_1
+(11 rows)
 
 SELECT
-    (SELECT g.i FROM (
-        (SELECT * FROM generate_series(1, 2) ORDER BY 1)
+    ARRAY(SELECT f.i FROM (
+        (SELECT d + g.i FROM generate_series(4, 30, 3) d ORDER BY 1)
         UNION ALL
-        (SELECT * FROM generate_series(1, 2) ORDER BY 1)
+        (SELECT d + g.i FROM generate_series(0, 30, 5) d ORDER BY 1)
     ) f(i)
-    ORDER BY f.i LIMIT 1)
+    ORDER BY f.i LIMIT 10)
 FROM generate_series(1, 3) g(i);
- i 
----
- 1
- 2
- 3
+            array             
+------------------------------
+ {1,5,6,8,11,11,14,16,17,20}
+ {2,6,7,9,12,12,15,17,18,21}
+ {3,7,8,10,13,13,16,18,19,22}
 (3 rows)
 
 reset enable_seqscan;

src/test/regress/sql/inherit.sql

@@ -442,21 +442,21 @@ ORDER BY x, y;
 -- exercise rescan code path via a repeatedly-evaluated subquery
 explain (costs off)
 SELECT
-    (SELECT g.i FROM (
-        (SELECT * FROM generate_series(1, 2) ORDER BY 1)
+    ARRAY(SELECT f.i FROM (
+        (SELECT d + g.i FROM generate_series(4, 30, 3) d ORDER BY 1)
         UNION ALL
-        (SELECT * FROM generate_series(1, 2) ORDER BY 1)
+        (SELECT d + g.i FROM generate_series(0, 30, 5) d ORDER BY 1)
     ) f(i)
-    ORDER BY f.i LIMIT 1)
+    ORDER BY f.i LIMIT 10)
 FROM generate_series(1, 3) g(i);
 
 SELECT
-    (SELECT g.i FROM (
-        (SELECT * FROM generate_series(1, 2) ORDER BY 1)
+    ARRAY(SELECT f.i FROM (
+        (SELECT d + g.i FROM generate_series(4, 30, 3) d ORDER BY 1)
         UNION ALL
-        (SELECT * FROM generate_series(1, 2) ORDER BY 1)
+        (SELECT d + g.i FROM generate_series(0, 30, 5) d ORDER BY 1)
     ) f(i)
-    ORDER BY f.i LIMIT 1)
+    ORDER BY f.i LIMIT 10)
 FROM generate_series(1, 3) g(i);
 
 reset enable_seqscan;