500
(20 rows)
+--test rescan behavior of gather merge
+set enable_material = false;
+explain (costs off)
+select * from
+ (select string4, count(unique2)
+ from tenk1 group by string4 order by string4) ss
+ right join (values (1),(2),(3)) v(x) on true;
+ QUERY PLAN
+----------------------------------------------------------
+ Nested Loop Left Join
+ -> Values Scan on "*VALUES*"
+ -> Finalize GroupAggregate
+ Group Key: tenk1.string4
+ -> Gather Merge
+ Workers Planned: 4
+ -> Partial GroupAggregate
+ Group Key: tenk1.string4
+ -> Sort
+ Sort Key: tenk1.string4
+ -> Parallel Seq Scan on tenk1
+(11 rows)
+
+select * from
+ (select string4, count(unique2)
+ from tenk1 group by string4 order by string4) ss
+ right join (values (1),(2),(3)) v(x) on true;
+ string4 | count | x
+---------+-------+---
+ AAAAxx | 2500 | 1
+ HHHHxx | 2500 | 1
+ OOOOxx | 2500 | 1
+ VVVVxx | 2500 | 1
+ AAAAxx | 2500 | 2
+ HHHHxx | 2500 | 2
+ OOOOxx | 2500 | 2
+ VVVVxx | 2500 | 2
+ AAAAxx | 2500 | 3
+ HHHHxx | 2500 | 3
+ OOOOxx | 2500 | 3
+ VVVVxx | 2500 | 3
+(12 rows)
+
+reset enable_material;
reset enable_hashagg;
-- gather merge test with a LIMIT
explain (costs off)
select count(*) from tenk1 group by twenty;
+--test rescan behavior of gather merge
+set enable_material = false;
+
+explain (costs off)
+select * from
+ (select string4, count(unique2)
+ from tenk1 group by string4 order by string4) ss
+ right join (values (1),(2),(3)) v(x) on true;
+
+select * from
+ (select string4, count(unique2)
+ from tenk1 group by string4 order by string4) ss
+ right join (values (1),(2),(3)) v(x) on true;
+
+reset enable_material;
+
reset enable_hashagg;
-- gather merge test with a LIMIT