Обсуждение: NOTIFY man page still recommends rules

The NOTIFY man page writes

   When <command>NOTIFY</command> is used to signal the occurrence of
changes
   to a particular table, a useful programming technique is to put the
   <command>NOTIFY</command> in a rule that is triggered by table updates.

Is using rules here still best practice?  This was probably written
before statement triggers were available.

Even if yes, we might want to explain why, since we generally discourage
rule use otherwise.

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

Peter Eisentraut wrote:
> The NOTIFY man page writes
>
>    When <command>NOTIFY</command> is used to signal the occurrence of
> changes
>    to a particular table, a useful programming technique is to put the
>    <command>NOTIFY</command> in a rule that is triggered by table updates.
>
> Is using rules here still best practice?  This was probably written
> before statement triggers were available.
>
> Even if yes, we might want to explain why, since we generally discourage
> rule use otherwise.

I think it's easier to dodge the rules topic entirely here and just
mention statement triggers.  Using rules you cannot cover the truncate
case, for instance.

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

Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> Peter Eisentraut wrote:
>> Is using rules here still best practice?  This was probably written
>> before statement triggers were available.

> I think it's easier to dodge the rules topic entirely here and just
> mention statement triggers.  Using rules you cannot cover the truncate
> case, for instance.

+1

            regards, tom lane

On 8/2/16 1:31 PM, Alvaro Herrera wrote:
> I think it's easier to dodge the rules topic entirely here and just
> mention statement triggers.  Using rules you cannot cover the truncate
> case, for instance.

done

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