From: | Michael Paquier <michael(at)paquier(dot)xyz> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Andres Freund <andres(at)anarazel(dot)de>, pgsql-hackers(at)lists(dot)postgresql(dot)org |
Subject: | Re: ExecForceStoreMinimalTuple leaks memory like there's no tomorrow |
Date: | 2019-04-16 03:31:37 |
Message-ID: | 20190416033137.GB2673@paquier.xyz |
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Lists: | pgsql-hackers |
On Mon, Apr 15, 2019 at 10:46:56PM -0400, Tom Lane wrote:
> 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.
Open item added, as the root comes from 4da597ed.
--
Michael
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