On 29 August 2017 at 08:42, Jerry Regan <jerry.regan@xxxxxxxxxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> wrote: > > "David G. Johnston" <david.g.johnston@xxxxxxxxx> writes: > > On Mon, Aug 28, 2017 at 1:28 PM, Jerry Regan < > jerry.regan@xxxxxxxxxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxx> http://www.stuartbishop.net/ -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
