Horton

Re: MultiXact\SLRU buffers configuration

Thomas Munro <thomas.munro@gmail.com>

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From: Thomas Munro <thomas.munro@gmail.com>
To: Andrey Borodin <x4mmm@yandex-team.ru>
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: 2021-04-08T12:22:39Z
Lists: pgsql-hackers 
On Thu, Apr 8, 2021 at 7:24 PM Andrey Borodin <x4mmm@yandex-team.ru> wrote:
> I agree that this version of eviction seems much more effective and less intrusive than RR. And it's still LRU, which is important for subsystem that is called SLRU.
> shared->search_slotno is initialized implicitly with memset(). But this seems like a common practice.
> Also comment above "max_search = Min(shared->num_slots, MAX_REPLACEMENT_SEARCH);" does not reflect changes.
>
> Besides this patch looks good to me.

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.

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.