Horton

Re: MultiXact\SLRU buffers configuration

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Andrey Borodin <x4mmm@yandex-team.ru>
Cc: vignesh C <vignesh21@gmail.com>, Andrew Borodin <amborodin86@gmail.com>, i.lazarev@postgrespro.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 mailing list <pgsql-hackers@postgresql.org>
Date: 2024-01-28T12:49:31Z
Lists: pgsql-hackers 
On 2024-Jan-27, Andrey Borodin wrote:

> thanks for the ping! Most important parts of this patch set are discussed in [0]. If that patchset will be committed, I'll withdraw entry for this thread from commitfest.
> There's a version of Multixact-specific optimizations [1], but I hope they will not be necessary with effective caches developed in [0]. It seems to me that most important part of those optimization is removing sleeps under SLRU lock on standby [2] by Kyotaro Horiguchi. But given that cache optimizations took 4 years to get closer to commit, I'm not sure we will get this optimization any time soon...

I'd appreciate it if you or Horiguchi-san can update his patch to remove
use of usleep in favor of a CV in multixact, and keep this CF entry to
cover it.

Perhaps a test to make the code reach the usleep(1000) can be written
using injection points (49cd2b93d7db)?

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"La experiencia nos dice que el hombre peló millones de veces las patatas,
pero era forzoso admitir la posibilidad de que en un caso entre millones,
las patatas pelarían al hombre" (Ijon Tichy)

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.