2 files changed, 45 insertions, 0 deletions
diff --git a/src/test/regress/expected/tsrf.out b/src/test/regress/expected/tsrf.out
index 25be6b9ab13..d47b5f6ec57 100644
--- a/src/test/regress/expected/tsrf.out
+++ b/src/test/regress/expected/tsrf.out
@@ -83,6 +83,39 @@ SELECT generate_series(1, generate_series(1, 3)), generate_series(2, 4);
 
 CREATE TABLE few(id int, dataa text, datab text);
 INSERT INTO few VALUES(1, 'a', 'foo'),(2, 'a', 'bar'),(3, 'b', 'bar');
+-- SRF with a provably-dummy relation
+explain (verbose, costs off)
+SELECT unnest(ARRAY[1, 2]) FROM few WHERE false;
+              QUERY PLAN              
+--------------------------------------
+ ProjectSet
+   Output: unnest('{1,2}'::integer[])
+   ->  Result
+         One-Time Filter: false
+(4 rows)
+
+SELECT unnest(ARRAY[1, 2]) FROM few WHERE false;
+ unnest 
+--------
+(0 rows)
+
+-- SRF shouldn't prevent upper query from recognizing lower as dummy
+explain (verbose, costs off)
+SELECT * FROM few f1,
+  (SELECT unnest(ARRAY[1,2]) FROM few f2 WHERE false OFFSET 0) ss;
+                   QUERY PLAN                   
+------------------------------------------------
+ Result
+   Output: f1.id, f1.dataa, f1.datab, ss.unnest
+   One-Time Filter: false
+(3 rows)
+
+SELECT * FROM few f1,
+  (SELECT unnest(ARRAY[1,2]) FROM few f2 WHERE false OFFSET 0) ss;
+ id | dataa | datab | unnest 
+----+-------+-------+--------
+(0 rows)
+
 -- SRF output order of sorting is maintained, if SRF is not referenced
 SELECT few.id, generate_series(1,3) g FROM few ORDER BY id DESC;
  id | g 
diff --git a/src/test/regress/sql/tsrf.sql b/src/test/regress/sql/tsrf.sql
index 0a1e8e56660..7c22529a0db 100644
--- a/src/test/regress/sql/tsrf.sql
+++ b/src/test/regress/sql/tsrf.sql
@@ -28,6 +28,18 @@ SELECT generate_series(1, generate_series(1, 3)), generate_series(2, 4);
 CREATE TABLE few(id int, dataa text, datab text);
 INSERT INTO few VALUES(1, 'a', 'foo'),(2, 'a', 'bar'),(3, 'b', 'bar');
 
+-- SRF with a provably-dummy relation
+explain (verbose, costs off)
+SELECT unnest(ARRAY[1, 2]) FROM few WHERE false;
+SELECT unnest(ARRAY[1, 2]) FROM few WHERE false;
+
+-- SRF shouldn't prevent upper query from recognizing lower as dummy
+explain (verbose, costs off)
+SELECT * FROM few f1,
+  (SELECT unnest(ARRAY[1,2]) FROM few f2 WHERE false OFFSET 0) ss;
+SELECT * FROM few f1,
+  (SELECT unnest(ARRAY[1,2]) FROM few f2 WHERE false OFFSET 0) ss;
+
 -- SRF output order of sorting is maintained, if SRF is not referenced
 SELECT few.id, generate_series(1,3) g FROM few ORDER BY id DESC;