Horton

Re: MultiXact\SLRU buffers configuration

x4mmm@yandex-team.ru

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From: "Andrey M. Borodin" <x4mmm@yandex-team.ru>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
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: 2024-04-07T19:13:12Z
Lists: pgsql-hackers 

> On 7 Apr 2024, at 21:41, Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> 
> Well, it would be nice to have *some* test, but as you say it is way
> more complex than the thing being tested, and it zooms in on the
> functioning of the multixact creation in insane quantum-physics ways ...
> to the point that you can no longer trust that multixact works the same
> way with the test than without it.  So what I did is manually run other
> tests (pgbench) to verify that the corner case in multixact creation is
> being handled correctly, and pushed the patch after a few corrections,
> in particular so that it would follow the CV sleeping protocol a little
> more closely to what the CV documentation suggests, which is not at all
> what the patch did.  I also fixed a few comments that had been neglected
> and changed the name and description of the CV in the docs.

That's excellent! Thank you!

> Now, maybe we can still add the test later, but it needs a rebase.

Sure. 'wait' injection points are there already, so I'll produce patch with "prepared" injection points and re-implement test on top of that. I'll put it on July CF.


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.