Re: Optional message to user when terminating/cancelling backend

On Thu, 22 Jun 2017 09:24:54 +0900
Michael Paquier <michael(dot)paquier(at)gmail(dot)com> wrote:

> On Wed, Jun 21, 2017 at 11:42 PM, Daniel Gustafsson <daniel(at)yesql(dot)se> wrote:
> > The message is truncated in SetBackendCancelMessage() for safety, but
> > pg_{cancel|terminate}_backend() could throw an error on too long message, or
> > warning truncation, to the caller as well. Personally I think a warning is the
> > appropriate response, but I don’t really have a strong opinion.
>
> And a NOTICE? That's what happens for relation name truncation. You
> are right that having a check in SetBackendCancelMessage() makes the
> most sense as bgworkers could just call the low level API. Isn't the
> concept actually closer to just a backend message? This slot could be
> used for other purposes than cancellation.

+1 for NOTICE. The message truncation seems to be a kind of helpful
information rather than a likely problem as long as pg_terminated_backend
exits successfully.

https://www.postgresql.org/docs/10/static/runtime-config-logging.html#runtime-config-severity-levels

> --
> Michael

--
Yugo Nagata <nagata(at)sraoss(dot)co(dot)jp>