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Re: VM corruption on standby

Andrey Borodin <x4mmm@yandex-team.ru>

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From: Andrey Borodin <x4mmm@yandex-team.ru>
To: Aleksander Alekseev <aleksander@tigerdata.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Melanie Plageman <melanieplageman@gmail.com>
Date: 2025-08-07T15:54:45Z
Lists: pgsql-hackers 

> On 7 Aug 2025, at 17:09, Aleksander Alekseev <aleksander@tigerdata.com> wrote:
> 
> If my understanding is correct, we should make a WAL record with the
> XLH_LOCK_ALL_FROZEN_CLEARED flag *before* we modify the VM but within
> the same critical section (in order to avoid race conditions within
> the same backend).

Well, the test passes because you moved injection point to a very safe position. I can't comment anything on other aspects of moving visibilitymap_clear() around.
The approach seems viable to me, but I'd like to have understanding why PD_ALL_VISIBLE in a heap page header did not save the day before fixing anything.


Best regards, Andrey Borodin.

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Revert "Get rid of WALBufMappingLock"

  2. Get rid of WALBufMappingLock

  3. Split WaitEventSet functions to separate source file

  4. Add WL_EXIT_ON_PM_DEATH pseudo-event.