Horton

Re: MultiXact\SLRU buffers configuration

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: "Andrey M. Borodin" <x4mmm@yandex-team.ru>, 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>, 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: 2024-08-21T06:26:05Z
Lists: pgsql-hackers

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On Wed, Aug 21, 2024 at 12:46:31PM +0900, Michael Paquier wrote:
> Sorry, I should have split that for clarity (one patch for the GUC,
> one to change the test to use CACHED/LOAD).  It is not an error
> though: if we don't have a controlled way to disable the stats of the
> module, then the test would fail when calling the cached callback
> because we'd try to allocate some memory for the dshash entry in
> pgstats.
> 
> The second effect of initializing the shmem state of the module with
> shared_preload_libraries is condition variables are set up for the
> sake if the test, removing the dependency to the SQL load() call.
> Both are OK, but I'd prefer introducing one use case for these two
> macros in the tree, so as these can be used as a reference in the
> future when developing new tests.

In short, here is a better patch set, with 0001 and 0002 introducing
the pieces that the test would need to be able to use the LOAD() and
CACHED() macros in 0003:
- 0001: Add shmem callbacks to initialize shmem state of
injection_points with shared_preload_libraries.
- 0002: Add a GUC to control if the stats of the module are enabled.
By default, they are disabled as they are only needed in the TAP test
of injection_points for the stats.
- 0003: Update the SLRU test to use INJECTION_POINT_LOAD and
INJECTION_POINT_CACHED with injection_points loaded via
shared_preload_libraries, removing the call to
injection_points_load() in the perl test.

What do you think?
--
Michael

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.