Re: PHJ file leak.

On Tue, Nov 12, 2019 at 1:24 AM Kyotaro Horiguchi
<horikyota.ntt@gmail.com> wrote:
> Hello. While looking a patch, I found that PHJ sometimes complains for
> file leaks if accompanied by LIMIT.

Oops.

> Repro is very simple:
>
> create table t as (select a, a as b from generate_series(0, 999999) a);
> analyze t;
> select t.a from t join t t2 on (t.a = t2.a) limit 1;
>
> Once in several (or dozen of) times execution of the last query
> complains as follows.
>
> WARNING:  temporary file leak: File 15 still referenced
> WARNING:  temporary file leak: File 17 still referenced

Ack.  Reproduced here.

> This is using PHJ and the leaked file was a shared tuplestore for
> outer tuples, which was opend by sts_parallel_scan_next() called from
> ExecParallelHashJoinOuterGetTuple(). It seems to me that
> ExecHashTableDestroy is forgeting to release shared tuplestore
> accessors. Please find the attached.

Thanks for the patch!  Yeah, this seems correct, but I'd like to think
about it some more before committing.  I'm going to be a bit tied up
with travel so that might be next week.