Horton

Re: MultiXact\SLRU buffers configuration

vignesh C <vignesh21@gmail.com>

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From: vignesh C <vignesh21@gmail.com>
To: i.lazarev@postgrespro.ru
Cc: Andrey Borodin <x4mmm@yandex-team.ru>, Yura Sokolov <y.sokolov@postgrespro.ru>, Andres Freund <andres@anarazel.de>, Thomas Munro <thomas.munro@gmail.com>, Gilles Darold <gilles@darold.net>, Tomas Vondra <tomas.vondra@enterprisedb.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Alexander Korotkov <aekorotkov@gmail.com>, Anastasia Lubennikova <a.lubennikova@postgrespro.ru>, Daniel Gustafsson <daniel@yesql.se>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2023-01-03T13:01:59Z
Lists: pgsql-hackers 
On Fri, 19 Aug 2022 at 21:18, <i.lazarev@postgrespro.ru> wrote:
>
> Andrey Borodin wrote 2022-08-18 06:35:
> >
> > I like the idea of one knob instead of one per each SLRU. Maybe we
> > even could deduce sane value from NBuffers? That would effectively
> > lead to 0 knobs :)
> >
> > Your patch have a prefix "v22-0006", does it mean there are 5 previous
> > steps of the patchset?
> >
> > Thank you!
> >
> >
> > Best regards, Andrey Borodin.
>
> Not sure it's possible to deduce from NBuffers only.
> slru_buffers_scale_shift looks like relief valve for systems with ultra
> scaled NBuffers.
>
> Regarding v22-0006 I just tried to choose index unique for this thread
> so now it's fixed to 0001 indexing.

The patch does not apply on top of HEAD as in [1], please post a rebased patch:

=== Applying patches on top of PostgreSQL commit ID
325bc54eed4ea0836a0bb715bb18342f0c1c668a ===
=== applying patch ./v23-0001-bucketed-SLRUs-simplified.patch
patching file src/include/miscadmin.h
...
patching file src/backend/utils/misc/guc.c
Hunk #1 FAILED at 32.
Hunk #2 FAILED at 2375.
2 out of 2 hunks FAILED -- saving rejects to file
src/backend/utils/misc/guc.c.rej

[1] - http://cfbot.cputube.org/patch_41_2627.log

Regards,
Vignesh

Commits

  1. Rework new SLRU test with injection points

  2. injection_point: Add injection_points.stats

  3. injection_points: Add initialization of shmem state when loading module

  4. Add injection-point test for new multixact CV usage

  5. Use conditional variable to wait for next MultiXact offset

  6. Improve performance of subsystems on top of SLRU

  7. Adjust VACUUM hastup LP_REDIRECT comments.

  8. Test replay of regression tests, attempt II.