Re: Changing the state of data checksums in a running cluster

> On 6 Apr 2026, at 19:00, Alexander Lakhin <exclusion(at)gmail(dot)com> wrote:
>
> Hello Daniel,
>
> 04.04.2026 00:46, Daniel Gustafsson wrote:
>> After many more runs on CI I ended up pushing this version, and I see BF
>> members being angry due the test not waiting for the launcher to exit. I am
>> working on a fix right now.
>>
>
> Maybe this is already known or even expected, but I'd still like to let
> you know that starting from f19c0ecca, I'm observing checksum errors in a
> running instance.

Thanks a lot for looking, and reporting!

> I'm getting, e.g.:
> 2026-04-06 18:09:12.077 EEST|postgres|regress_215|69d3cc86.3bfbdc|PANIC: page verification failed, calculated checksum 40178 but expected 50558, buffer will be zeroed

I believe this is related to the same issue with visibilitymap clearing which
is discussed in:

https://postgr.es/m/CAAKRu_bn+e7F4yPFBgFbnP+syJRKyNK092bjD2LKvZW7O4Svag@mail.gmail.com

It was raised in this thread as well, but fixing it was deemed to be an
independent effort (and the above thread found it independently of the work in
this thread).

> I reproduce it rather easily (within 30 minutes) with 600 instances of
> "sqlsmith --max-queries=1000" running against separate empty databases, on
> my workstation with Ryzen 7900. I think I can compose a self-contained
> repro, if needed... If you need more information/diagnostics, I'd be glad
> to help.

If you have, or can easily make, a reproducer which can be boile down into a
test case then that would for sure help.

--
Daniel Gustafsson