Re: Bug in logical decoding with DDL and subtransactions

Hello Tom,

29.09.2026 21:31, Tom Lane wrote:
> Bingshuai Li<lucian1412(at)outlook(dot)com> writes:
>>> What's the reason to consider this as a worse problem in 19 than in
>>> previous releases?
>> There isn't one -- I asked because 19 GA was approaching and the bug
>> was reported against 19. Fixing it in all stable branches for the
>> November minors sounds right.
> While it's not any worse for v19 than older branches, it would be sad
> if this isn't fixed for v19 GA, since we have that scheduled ahead of
> the November minors.
>
> Also, of late the test_decoding/sql/ddl.sql test has been failing
> often enough in the buildfarm to be quite annoying. So I'd like to
> see this fixed sooner not later. (It's not very clear to me why
> we are suddenly able to see this old bug in the regression tests.
> The part of ddl.sql that's crashing hasn't changed in years, but
> BF member "prion" has failed multiple times in the past two weeks.
> Do we have a theory about that that's better than hand-wavy
> "some change in timing"?)

Besides prion, skink managed to trigger that assert too: [1]. It didn't run
tests from 2026-09-08 to 2026-09-25 [2], and never failed this test before,
so I guess the change which affected the test was on Sep 15: a4b26b8f7
(the very first prion's failure includes this commit [3]). I can reproduce
this failure under Valgrind locally, but not reliably enough to bisect it
quickly.

[1] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=skink&dt=2026-09-28%2003%3A25%3A19
[2] https://buildfarm.postgresql.org/cgi-bin/show_history.pl?nm=skink&br=master
[3] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=prion&dt=2026-09-15%2021%3A39%3A57

Best regards,
Alexander