RuntimeAppend returns garbage when left join and where used

[dimarick]

Schema and data:

create table parent (
  id SERIAL NOT NULL,
  owner_id INTEGER NOT NULL
);

create table child (
  parent_id INTEGER NOT NULL,
  owner_id INTEGER NOT NULL
);

create table child_nopart (
  parent_id INTEGER NOT NULL,
  owner_id INTEGER NOT NULL
);

insert into parent (owner_id) values (1), (2), (3), (3);
insert into child (parent_id, owner_id) values (1, 1), (2, 2), (3, 3), (5, 3);
insert into child_nopart (parent_id, owner_id) values (1, 1), (2, 2), (3, 3), (5, 3);

select create_hash_partitions('child', 'owner_id', 2);

The select SQL to reproduce:

select *
  from parent
  left join child on child.parent_id = parent.id and child.owner_id = parent.owner_id
  where parent.owner_id = 3 and parent.id in (3, 4);

Actual result:

id	owner_id	parent_id	owner_id
3	3		3		3
3	3		5		3
4	3		3		3
4	3		5		3

https://explain.depesz.com/s/ioD5K

All of this will work as expected:

select *
  from parent
  left join child on child.parent_id = parent.id and child.owner_id = 3
  where parent.owner_id = 3 and parent.id in (3, 4);

select *
  from parent
  left join child_1 child on child.parent_id = parent.id and child.owner_id = parent.owner_id
  where parent.owner_id = 3 and parent.id in (3, 4);

select *
  from parent
  left join child_nopart child on child.parent_id = parent.id and child.owner_id = parent.owner_id
  where parent.owner_id = 3 and parent.id in (3, 4);

select *
  from parent
  left join child on child.parent_id = parent.id and child.owner_id = parent.owner_id
  where parent.owner_id = 3;

Result:

id	owner_id	parent_id	owner_id
3	3		3		3
4	3		<null>		<null>

Affected version 1.3.2

[funbringer]

Hi @dimarick,

We're investigating the problem you've reported. As a temporary workaround, you can disable RuntimeAppend using:

alter system set pg_pathman.enable_runtimeappend = f;

and reload PostgreSQL's config (via pg_ctl reload).

Our current dev branch (rel_future_beta) is not affected, which means that we've already fixed this, but it might be hard to backport this fix to master. I'll tell the details later.

[funbringer]

Version 1.4 is out!