Re: "ERROR: deadlock detected" when replicating TRUNCATE

On Tue, May 18, 2021 at 6:19 AM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
>
> On Mon, May 17, 2021 at 8:13 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > On Mon, May 17, 2021 at 3:05 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> > >
> > > On Mon, May 17, 2021 at 12:30 PM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
> > >
> > > > PSA a patch adding a test for this scenario.
> > >
> > > I am not sure this test case is exactly targeting the problematic
> > > behavior because that will depends upon the order of execution of the
> > > apply workers right?
> > >
> >
> > Yeah, so we can't guarantee that this test will always reproduce the
> > problem but OTOH, I have tried two times and it reproduced both times.
> > I guess we don't have a similar test where Truncate will replicate to
> > two subscriptions, otherwise, we would have caught such a problem.
> > Having said that, I am fine with leaving this test if others feel so
> > on the grounds that it won't always lead to the problem reported.
> >
>
> If there is any concern that the problem won't always happen then I
> think we should just increase the numbers of subscriptions.
>
> Having more simultaneous subscriptions (e.g. I have tried 4). will
> make it much more likely for the test to encounter the deadlock, and
> it probably would also be quite a useful worker stress test in it's
> own right.
>

I don't think we need to go that far.

> ~~
>
> Also, should this test be in the 010_truncate,pl,
>

+1 for keeping it in 010_truncate.pl but remove the synchronous part
of it from the testcase and comments as that is not required.

--
With Regards,
Amit Kapila.