Re: NOTIFY in Background Worker

2015-11-03 9:35 GMT+01:00 Andres Freund <andres(at)anarazel(dot)de>:

> On 2015-11-03 17:19:43 +1100, Haribabu Kommi wrote:
> > On Sat, Aug 29, 2015 at 12:55 PM, Thomas Munro
> > <thomas(dot)munro(at)enterprisedb(dot)com> wrote:
> > > On Sat, Aug 29, 2015 at 9:03 AM, Thomas Munro
> > > <thomas(dot)munro(at)enterprisedb(dot)com> wrote:
> > > This made me wonder what happens if a background worker calls LISTEN.
> > > NotifyMyFrontEnd simply logs the notifications, since there is no
> remote
> > > libpq to sent a message to. Perhaps a way of delivering to background
> > > workers could be developed, though of course there are plenty of other
> kinds
> > > of IPC available already.
> >
> > With this commit - bde39eed0cafb82bc94c40e95d96b5cf47b6f719, it is not
> possible
> > to execute Notify commands inside a parallel worker. Can't we change
> > it as disable both listen and notify commands inside a background worker?
>
> Well, parallel workers are something different from general background
> workers. I don't see why it'd make sense to allow listen/notify there,
> given the rest of the restrictions?
>

I though about this possibility and I am thinking, so NOTIFY can be pretty
useful there.

The background workers can be used for running AT TIME tasks - run import
every 10 minutes. The notification can be useful for starting AFTER tasks
where the required previous steps should be committed.

If we use workers more for execution custom code (PLpgSQL, PLPython, ...)
then notification mechanism can be interesting (both directions).

Regards

Pavel

Andres
>
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