Horton

RE: Introduce XID age and inactive timeout based replication slot invalidation

Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com>

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From: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>
To: Michail Nikolaev <michail.nikolaev@gmail.com>, Nisha Moond <nisha.moond412@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Peter Smith <smithpb2250@gmail.com>, vignesh C <vignesh21@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, shveta malik <shveta.malik@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Ajin Cherian <itsajin@gmail.com>, Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-12-26T06:02:20Z
Lists: pgsql-hackers

Commits

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

  1. Add a test for commit ac0e33136a using the injection point.

  2. Invalidate inactive replication slots.

  3. Fix incorrect slot type in BuildTupleHashTableExt

  4. Allow synced slots to have their inactive_since.

  5. Change last_inactive_time to inactive_since in pg_replication_slots.

  6. Track last_inactive_time in pg_replication_slots.

  7. Track invalidation_reason in pg_replication_slots.

  8. Add option force_initdb to PostgreSQL::Test::Cluster:init()

  9. Add a failover option to subscriptions.

  10. Allow setting failover property in the replication command.

  11. Allow to enable failover property for replication slots via SQL API.

  12. Track conflict_reason in pg_replication_slots.

  13. Log messages for replication slot acquisition and release.

  14. Remove vacuum_defer_cleanup_age

  15. Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xids

  16. meson: Add initial version of meson based build system

On Tuesday, December 24, 2024 8:57 PM Michail Nikolaev <michail.nikolaev@gmail.com>  wrote:

Hi,

> Yesterday I got a strange set of test errors, probably somehow related to
> that patch. It happened on changed master branch (based on
> d96d1d5152f30d15678e08e75b42756101b7cab6) but I don't think my changes were
> affecting it.
> 
> My setup is a little bit tricky: Windows 11 run WSL2 with Ubuntu, meson.
> 
> So, `recovery ` suite started failing on:
> 
> 1) at /src/test/recovery/t/http://019_replslot_limit.pl line 530.
> 2) at /src/test/recovery/t/http://040_standby_failover_slots_sync.pl line
>    198.
> 
> It was failing almost every run, one test or another. I was lurking around
> for about 10 min, and..... it just stopped failing. And I can't reproduce it
> anymore.
> 
> But I have logs of two fails. I am not sure if it is helpful, but decided to
> mail them here just in case.

Thanks for reporting the issue.

After checking the log, I think the failure is caused by the unexpected
behavior of the local system clock.

It's clear from the '019_replslot_limit_primary4.log'[1] that the clock went
backwards which makes the slot's inactive_since go backwards as well. That's
why the last testcase didn't pass.

And for 040_standby_failover_slots_sync, we can see that the clock of standby
lags behind that of the primary, which caused the inactive_since of newly synced
slot on standby to be earlier than the one on the primary.

So, I think it's not a bug in the committed patch but an issue in the testing
environment. Besides, since we have not seen such failures on BF, I think it
may not be necessary to improve the testcases.

[1]
2024-12-24 01:37:19.967 CET [161409] sub STATEMENT:  START_REPLICATION SLOT "lsub4_slot" LOGICAL 0/0 (proto_version '4', streaming 'parallel', origin 'any', publication_names '"pub"')
...
2024-12-24 01:37:20.025 CET [161447] 019_replslot_limit.pl LOG:  statement: SELECT '0/30003D8' <= replay_lsn AND state = 'streaming'
...
2024-12-24 01:37:19.388 CET [161097] LOG:  received fast shutdown request

Best Regards,
Hou zj