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Re: Changing the state of data checksums in a running cluster

Tomas Vondra <tomas@vondra.me>

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From: Tomas Vondra <tomas@vondra.me>
To: Daniel Gustafsson <daniel@yesql.se>
Cc: Andres Freund <andres@anarazel.de>, Bernd Helmle <mailings@oopsware.de>, Michael Paquier <michael@paquier.xyz>, Michael Banck <mbanck@gmx.net>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2026-03-15T22:56:27Z
Lists: pgsql-hackers 
On 3/12/26 23:56, Daniel Gustafsson wrote:
>> On 12 Mar 2026, at 00:56, Daniel Gustafsson <daniel@yesql.se> wrote:
> 
> One thing I forgot to mention was that this patch uncovered the same vmap (and
> fsm) issue as is being discussed in [0].  At the time I didn't connect the dots
> that it was an issue even without this patch so I tried to solve it as part of
> this work.  After speaking with Andres I ripped out my attempts and will let
> the other thread take care of the issue independently of this.
> 

Yeah, this is quite annoying. It makes 100% sense to wait for the
visibility map to get fixed (by properly WAL-logging it). But I'm not
aware of any such fixes for the FSM though, so I what's the plan for
that? IMO the right solution would be to do proper WAL for FSM, but that
seems like a significant amount of work.


regards

-- 
Tomas Vondra

Commits

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

  1. Use correct datatype for PID

  2. Improve comments in online checksums code

  3. Fix checksum state transition during promotion

  4. Fix regex searching for page verification failures in tests

  5. Apply data-checksum worker throttling parameters

  6. Skip WAL for unlogged main fork during online checksum enable

  7. Fix data_checksum GUC show_hook

  8. Improve database detection logic in datachecksumsworker

  9. Improve handling of concurrent checksum requests

  10. Typo and spelling fixups for online checksums

  11. Fix invalid checksum state transition in checkpoints

  12. Handle data_checksum state changes during launcher_exit

  13. Test improvements for online checksums

  14. Prevent pg_enable/disable_data_checksums() on standby

  15. Test stabilization for online checksums

  16. Make data checksum tests more resilient for slow machines

  17. Formalize WAL record for XLOG_CHECKPOINT_REDO

  18. Revert "Get rid of WALBufMappingLock"

  19. Get rid of WALBufMappingLock

  20. Improve grammar of options for command arrays in TAP tests