On Fri, Jun 25, 2021 at 12:20 AM PG Bug reporting form
<noreply@postgresql.org> wrote:
>
> The offending (the one that leaved a "valid" clogGroupNext) proccess is
> 60d48c2d.ea21. It looks like it got from the
> pg_atomic_compare_exchange_u32() the nextidx value that was written in the
> clogGroupFirst by the process 60d48c2e.ebc5, and exited just after that.
>
Your analysis seems to be in the right direction. Can you try by
setting clogGroupNext to INVALID_PGPROCNO
(pg_atomic_write_u32(&proc->clogGroupNext, INVALID_PGPROCNO);) before
we return false in the first while(true) loop in function
TransactionGroupUpdateXidStatus()?
I think this should be reproducible on all branches from HEAD till
v11. Have you tried in any other branch? I'll also try to reproduce
it.
--
With Regards,
Amit Kapila.
