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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>, Heikki Linnakangas <hlinnaka@iki.fi>
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: 2026-03-27T23:13:40Z
Lists: pgsql-hackers 
Hi Daniel,

On 3/27/26 23:03, Daniel Gustafsson wrote:
> The attached rebase contains lots more polish, mostly renaming variable names
> for clarity, tidying up comments and documentation and some smaller bits of
> cleanup like moving more code out of xlog.c.
> 
> This version runs all the tests in a normal test-run, with a few of them pared
> down with larger runs gated by PG_TEST_EXTRA.  I thinkt the tests are still too
> expensive in the event of getting committed, but it's helpful to have them
> during dev and test.  Executing pgbench sometimes fails in CI but I've been
> unable to reproduce that so not entirely sure what is going on there.
> 
> Heikki, Andres and Tomas; as you have been reviewing this patchset, what do you
> feel is left for considering this for commit?  (Apart from figuring out the CI
> test thing mentioned above which I think is a buildsystem issue.) I think 0001
> could be considered independently of 0002 and is cleanup in it's own right.
> 

Nothing particular comes to my mind, really. All the suggestions and
ideas I've had regarding the patch I've already shared during the
earlier reviews/testing. I'll take a look over the weekend, but I don't
expect to find anything, especially now that Heikki reviewed it.

The only thing that bothered me were the checksum failures in VM/FSM.
The VM failures were fixed (right?), and the FSM failures are expected
because we don't WAL-log that (and so no FPIs either).

That's a bit unfortunate, but it's not a new issue or the fault of this
patch, and it doesn't make it any worse. Fine with me.

However, won't this be a problem for the TAP tests? I mean, what happens
after a crash/restart, that might have corrupted the FSM? Won't that
result in a test failure?


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