Re: pg_recvlogical prints bogus error when interrupted

On Fri, Oct 21, 2022 at 7:52 AM Kyotaro Horiguchi
<horikyota(dot)ntt(at)gmail(dot)com> wrote:
>
> > +1. How about emitting a message like its friend pg_receivewal, like
> > the attached patch?
>
> I'm not a fan of treating SIGINT as an error in this case. It calls
> prepareToTerminate() when time_to_abort and everything goes fine after
> then. So I think we should do the same thing after receiving an
> interrupt. This also does file-sync naturally as a part of normal
> shutdown. I'm also not a fan of doing fsync at error.

I think the pg_recvlogical can gracefully exit on both SIGINT and
SIGTERM to keep things simple.

> > > I also then noticed that we don't fsync the output file in cases of errors -
> > > that seems wrong to me? Looks to me like that block should be moved till after
> > > the error:?
> >
> > How about something like the attached patch?

The attached patch (pg_recvlogical_graceful_interrupt.text) has a
couple of problems, I believe. We're losing prepareToTerminate() with
keepalive true and we're not skipping pg_log_error("unexpected
termination of replication stream: %s" upon interrupt, after all we're
here discussing how to avoid it.

I came up with the attached v2 patch, please have a look.

--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com