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

Hi,

On Mon, Jun 08, 2026 at 09:00:17PM +0800, Xuneng Zhou wrote:
> I tweaked the reproducer based on the theory outlined above. The main
> changes from the original reproducer are:
>
> 1) blocks at logical-walsender-after-slot-acquire in walsender.c,
> before the decoding context is created and before the reader starts
> from restart_lsn, matching the delay set by Alexander

> 2) Forces the first read to occur during promotion. It inserts rows
> 1..4, waits for replay, starts promotion with pg_promote(false), holds
> startup at startup-logical-decoding-status-change-end-of-recovery,
> then wakes the walsender.

Yeah, so this existing startup-logical-decoding-status-change-end-of-recovery
injection point already exists in the code tree and is also called after
CleanupAfterArchiveRecovery() and before RECOVERY_STATE_DONE change in
StartupXLOG().

So this is the same window as the new injection point that was added in the new
tests in v1-0002 shared up-thread [1].

That said, I think I prefer the v1-0002 shared up-thread [1] approach for the
tests as:

- the injection point name clearly describes the tested condition
- no new injection point is added in walsender.c (it pauses startup mid-promotion
and lets the walsender connect)
- the test relies on one injection point (not two)

[1]: https://postgr.es/m/aiaBtENl7tTf2MM8%40bdtpg

Regards,

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