Horton

Re: MultiXact\SLRU buffers configuration

x4mmm@yandex-team.ru

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From: Andrey Borodin <x4mmm@yandex-team.ru>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: 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: 2022-02-19T05:34:36Z
Lists: pgsql-hackers 

> 8 апр. 2021 г., в 17:22, Thomas Munro <thomas.munro@gmail.com> написал(а):
> 
> Thanks!  I chickened out of committing a buffer replacement algorithm
> patch written 11 hours before the feature freeze, but I also didn't
> really want to commit the GUC patch without that.  Ahh, if only we'd
> latched onto the real problems here just a little sooner, but there is
> always PostgreSQL 15, I heard it's going to be amazing.  Moved to next
> CF.

Hi Thomas!

There's feature freeze approaching again. I see that you are working on moving SLRUs to buffer pools, but it is not clear to which PG version it will land. And there is 100% consensus that first patch is useful and helps to prevent big issues. Maybe let's commit 1'st step without lifting default xact_buffers limit? Or 1st patch as-is with any simple technique that prevents linear search in SLRU buffers.

Best regards, Andrey Borodin.

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.