Re: ExecForceStoreMinimalTuple leaks memory like there's no tomorrow

Hi,

On 2019-04-15 22:46:56 -0400, Tom Lane wrote:
> Using HEAD,
>
> create table t1 as select generate_series(1,40000000) id;
> vacuum analyze t1;
> explain select * from t1, t1 t1b where t1.id = t1b.id;
> -- should indicate a hash join
> explain analyze select * from t1, t1 t1b where t1.id = t1b.id;
>
> ... watch the process's memory consumption bloat. (It runs for
> awhile before that starts to happen, but eventually it goes to
> a couple of GB.)
>
> It looks to me like the problem is that ExecHashJoinGetSavedTuple
> calls ExecForceStoreMinimalTuple with shouldFree = true, and
> ExecForceStoreMinimalTuple's second code branch simply ignores
> the requirement to free the supplied tuple.

Thanks for finding. The fix is obviously easy - but looking through the
code I think I found another similar issue. I'll fix both in one go
tomorrow.

Greetings,

Andres Freund