Horton

Re: t/035_standby_logical_decoding.pl might fail on attempt to read wrong timeline

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

View thread View on postgr.es
From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>
Cc: Alexander Lakhin <exclusion@gmail.com>, "xunengzhou@gmail.com" <xunengzhou@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2026-06-09T05:57:56Z
Lists: pgsql-hackers 
Hi Hayato-san,

On Tue, Jun 09, 2026 at 04:04:20AM +0000, Hayato Kuroda (Fujitsu) wrote:
> Dear Bertrand, Xuneng,
> 
> Thanks for sharing the reproducer and opinion. I could now understand.
> 
> While seeing, I felt the same issue can happen even for the streaming case.
> Please see attached reproducer and possible fix.

I just had a quick look and I feel that's probably an issue too (good find!).
I think that your fix should use GetWALInsertionTimeLineIfSet() though (but I
only did a quick scan on your patch).

> Can you also include that point? Or this thread discusses only for the logical case?
> If separated, I can take initiative for the streaming part, after the logical decoding
> case.

I would says it's probably better to keep this thread focusing on Alexander's issue
(logical decoding). Once this thread is fixed, then I'd suggest to open a dedicated
thread for the streaming one (mentioning this thread and probably trying to mimic
its fix as close as possible).

Also I would suggest not to post "real" patches here as they conflict with mine
in the cfbot (means the cfbot won't tell me anymore if my patches need a rebase).
Please use .txt files or use "nocfbot" instead if you feel the need.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com

Commits

  1. Fix second race with timeline selection during promotion

  2. Remove TAP test for timeline lookup race with logical decoding on standbys

  3. Fix race with timeline selection in logical decoding during promotion

  4. Backport GetWALInsertionTimeLineIfSet()

  5. TAP test for logical decoding on standby