| From: | Andrey Borodin <x4mmm(at)yandex-team(dot)ru> |
|---|---|
| To: | Aleksander Alekseev <aleksander(at)tigerdata(dot)com> |
| Cc: | PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Melanie Plageman <melanieplageman(at)gmail(dot)com> |
| Subject: | Re: VM corruption on standby |
| Date: | 2025-08-09 15:53:54 |
| Message-ID: | DD626328-835F-4629-9420-C7CE3ABE8A26@yandex-team.ru |
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| Lists: | pgsql-hackers |
> On 9 Aug 2025, at 18:28, Andrey Borodin <x4mmm(at)yandex-team(dot)ru> wrote:
>
> Also I investigated that in a moment of kill -9 checkpointer flushes heap page to disk despite content lock. I haven't found who released content lock though.
I've written this message and understood: its LWLockReleaseAll().
0. checkpointer is going to flush a heap buffer but waits on content lock
1. client is resetting PD_ALL_VISIBLE from page
2. postmaster is killed and command client to go down
3. client calls LWLockReleaseAll() at ProcKill() (?)
4. checkpointer flushes buffer with reset PG_ALL_VISIBLE that is not WAL-logged to standby
5. subsequent deletes do not log resetting this bit
6. deleted data is observable on standby with IndexOnlyScan
Any idea how to fix this?
Best regards, Andrey Borodin.
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