Re: A problem about partitionwise join

create table p (k1 int, k2 int, val int) partition by range(k1, k2);
create table p_1 partition of p for values from (1,1) to (10,100);
create table p_2 partition of p for values from (10,100) to (20,200);

set enable_partitionwise_join to on;

explain (costs off)
select * from p as foo join p as bar on foo.k1 = bar.k1 and foo.k2 = bar.k2 and foo.k2 = 5;
               QUERY PLAN
-----------------------------------------
 Hash Join
   Hash Cond: (foo.k1 = bar.k1)
   ->  Append
         ->  Seq Scan on p_1 foo_1
               Filter: (k2 = 5)
         ->  Seq Scan on p_2 foo_2
               Filter: (k2 = 5)
   ->  Hash
         ->  Append
               ->  Seq Scan on p_1 bar_1
                     Filter: (k2 = 5)
               ->  Seq Scan on p_2 bar_2
                     Filter: (k2 = 5)
(13 rows)