Thread: RE: Using per-transaction memory contexts for storing decoded tuples

RE: Using per-transaction memory contexts for storing decoded tuples

From
"Hayato Kuroda (Fujitsu)"
Date:
Hi,

> We have several reports that logical decoding uses memory much more
> than logical_decoding_work_mem[1][2][3]. For instance in one of the
> reports[1], even though users set logical_decoding_work_mem to
> '256MB', a walsender process was killed by OOM because of using more
> than 4GB memory.

I appreciate your work on logical replication and am interested in the thread.
I've heard this issue from others, and this has been the barrier to using logical
replication. Please let me know if I can help with benchmarking, other
measurements, etc.

Best regards,
Hayato Kuroda
FUJITSU LIMITED


Re: Using per-transaction memory contexts for storing decoded tuples

From
Masahiko Sawada
Date:
Hi,

On Mon, Sep 16, 2024 at 10:56 PM Hayato Kuroda (Fujitsu)
<kuroda.hayato@fujitsu.com> wrote:
>
> Hi,
>
> > We have several reports that logical decoding uses memory much more
> > than logical_decoding_work_mem[1][2][3]. For instance in one of the
> > reports[1], even though users set logical_decoding_work_mem to
> > '256MB', a walsender process was killed by OOM because of using more
> > than 4GB memory.
>
> I appreciate your work on logical replication and am interested in the thread.
> I've heard this issue from others, and this has been the barrier to using logical
> replication. Please let me know if I can help with benchmarking, other
> measurements, etc.

Thank you for your interest in this patch. I've just shared some
benchmark results (with a patch) that could be different depending on
the environment[1]. I would be appreciated if you also do similar
tests and share the results.

Regards,

[1] https://www.postgresql.org/message-id/CAD21AoAaN4jaJ%3DW%2BWprHvc0cGCf80SkiFQhRc6R%2BX3-05HAFqw%40mail.gmail.com

--
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com