Re: Transactions involving multiple postgres foreign servers, take 2

On Mon, 19 Oct 2020 at 20:37, Ashutosh Bapat
<ashutosh.bapat.oss@gmail.com> wrote:
>
> On Mon, Oct 19, 2020 at 2:37 PM tsunakawa.takay@fujitsu.com
> <tsunakawa.takay@fujitsu.com> wrote:
> >
> > Really.  I thought we were talking about canceling commits with Ctrl + C as you referred, right?  I couldn't
imagine,in production environments where many sessions are running transactions concurrently,  how the user (DBA) wants
andcan cancel each stuck session during commit one by one with Ctrl + C by hand.  I haven't seen such a feature exist
orbeen considered crucial that enables the user (administrator) to cancel running processing with Ctrl + C from the
side.
>
> Using pg_cancel_backend() and pg_terminate_backend() a DBA can cancel
> running query from any backend or terminate a backend. For either to
> work the backend needs to be interruptible. IIRC, Robert had made an
> effort to make postgres_fdw interruptible few years back.

Right. Also, We discussed having a timeout on the core side but I'm
concerned that the timeout also might not work if it's not
interruptible.

While using the timeout is a good idea, I have to think there is also
a certain number of the user who doesn't use this timeout as there is
a certain number of the users who doesn't use timeouts such as
statement_timeout. We must not ignore such users and It might not be
advisable to design a feature that ignores such users.

Regards,

--
Masahiko Sawada            http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services