| From: | Andrey Borodin <x4mmm(at)yandex-team(dot)ru> |
|---|---|
| To: | Melanie Plageman <melanieplageman(at)gmail(dot)com> |
| Cc: | Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>, Nazir Bilal Yavuz <byavuz81(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Andres Freund <andres(at)anarazel(dot)de>, tristan(dot)yim(at)gmail(dot)com |
| Subject: | Re: Checkpointer write combining |
| Date: | 2026-08-14 11:39:24 |
| Message-ID: | BDE96C3B-3179-4A5E-B3C2-005D35E4686C@yandex-team.ru |
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| Lists: | pgsql-hackers |
> On 19 Jul 2026, at 11:05, Andrey Borodin <x4mmm(at)yandex-team(dot)ru> wrote:
>
> I'll follow up with the bulkwrite and checkpointer patches next.
Hi!
I looked through 0007-0009 and did not find correctness issues.
The existing COPY test uses an unlogged relation, so it does not
exercise the WAL eligibility checks in
PrepareOrRejectEagerFlushBuffer(). I tried the same test with a regular
table and it consistently combined writes.
For deterministic results I used wal_writer_delay = '10ms'. With
synchronous_commit disabled, a fast COPY may otherwise finish before the
default 200ms WAL writer interval. fsync can remain disabled: the test
only needs the PostgreSQL WAL flush position to advance.
Perhaps the test could run the COPY case for both unlogged and regular
tables.
Best regards, Andrey Borodin.
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