Re: Deadlock detector fails to activate on a hot standby replica

On Tue, Jun 23, 2026 at 3:32 AM Vitaly Davydov <v(dot)davydov(at)postgrespro(dot)ru> wrote:
>
> Dear Fujii Masao, All
>
> While working on porting the patch to other majors, I've found that, the code
> in RegisterPinCountWaiter() (see below) should be improved because it doesn't
> unlock the bufHdr when the error is raised, as in LockBufferForCleanup().
> I guess it works, but it keeps the locks a bit longer.
>
> RegisterPinCountWaiter v5 patch code:
> ...
> if ((buf_state & BM_PIN_COUNT_WAITER) != 0 &&
> bufHdr->wait_backend_pgprocno != MyProcNumber)
> elog(ERROR, "multiple processes attempting to wait for pincount 1");
>
> RegisterPinCountWaiter proposed changes:
> ...
> if ((buf_state & BM_PIN_COUNT_WAITER) != 0 &&
> bufHdr->wait_backend_pgprocno != MyProcNumber)
> {
> UnlockBufHdr(bufHdr);
> elog(ERROR, "multiple processes attempting to wait for pincount 1");
> }
>
> What do you think?

You're right. Thanks for pointing out that!

I've updated the patch accordingly.

Regards,

--
Fujii Masao