Re: Undetected Deadlock

On Wed, 9 Feb 2022 at 23:50, Michael Harris <harmic(at)gmail(dot)com> wrote:
>
> On Mon, 7 Feb 2022 at 09:57, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > Do you want to try this and see if it actually adds any robustness with your buggy code?
>
> Sorry for the delayed response, & thanks for the patch.
>
> I wasn't able to test with our actual application because it could
> take days for it to actually trigger the problem, so I tested it with
> a simulation, which you can find here:
>
> https://github.com/harmic/pg_almloss

Thanks for writing a test case.

Could you specify the licence of that as The PostgreSQL Licence, to
allow it to be used as a permanent test case?
We can add other misbehaviors as well, as needed.

> With that simulation I could attach gdb to the backend and see that
> signal_pending & signal_due_at were being reset in the expected way,
> even when a missed interrupt was triggered.
>
> I'm convinced your patch improves robustness under the scenario we saw.

Cool, thanks

--
Simon Riggs http://www.EnterpriseDB.com/