Re: Create Action for psql when NOTIFY Recieved

Stuart,

Thank you!

I will investigate.

/s/jr
Consultant
Concerto GR
Mobile: 612.208.6601

Concerto - a composition for orchestra and a soloist

> On 29Aug, 2017, at 7:52 AM, Stuart Bishop <stuart(at)stuartbishop(dot)net> wrote:
>
> On 29 August 2017 at 08:42, Jerry Regan
> <jerry(dot)regan(at)concertoglobalresources(dot)com> wrote:
>> Tom,
>>
>> After a few minutes thought…..
>>
>> /s/jr
>> Consultant
>> Concerto GR
>> Mobile: 612.208.6601
>>
>> Concerto - a composition for orchestra and a soloist
>>
>>
>>
>> On 28Aug, 2017, at 6:08 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>
>> "David G. Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> writes:
>>
>> On Mon, Aug 28, 2017 at 1:28 PM, Jerry Regan <
>> jerry(dot)regan(at)concertoglobalresources(dot)com> wrote:
>>
>> My concern is how, after LISTENing in psql, I can tell it what to do when
>> the NOTItFY is received.
>>
>>
>> As far as I am aware you cannot.
>>
>>
>> Yes, and psql is not designed to do anything of its own accord,
>> so I think the answer is really "use another program”.
>>
>>
>> psql would be running on *nix.
>>
>> Let’s suppose for a moment that I piped the output of a psql instance to awk
>> or some similar program, configured to detect the NOTIFY. That program would
>> then spawn a process to actually perform the work, parameters being whatever
>> is part of the NOTIFY. Both this psql instance and the awk script would be
>> dedicated to this task.
>>
>> Given this is not intended in any way to be production quality code - in
>> fact, it’s intended to deliver XML to the client server for validation
>> (xmllint) in a development/test environment - do you see anything that
>> clearly won’t work? Also, this would be a very low volume connection.
>> Perhaps one NOTIFY in five minutes - or longer.
>>
>> Yes, it’s a hack.
>
> Or crib some code from
> http://initd.org/psycopg/docs/advanced.html#async-notify or
> https://godoc.org/github.com/lib/pq/listen_example , which is probably
> less effort than assembling this collection of hacks and trying to
> make it reliable. Most PostgreSQL APIs have support for notifications.
>
>
> --
> Stuart Bishop <stuart(at)stuartbishop(dot)net>
> http://www.stuartbishop.net/