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* Can the frontend get notifications from the postgres server?
@ 2003-06-17 04:39 Anagha Joshi <ajoshi@nulinkinc.com>
0 siblings, 1 reply; 10+ messages in thread
From: Anagha Joshi @ 2003-06-17 04:39 UTC (permalink / raw)
To: pgsql-admin@postgresql.org
^ permalink raw reply [nested|flat] 10+ messages in thread
* Re: Can the frontend get notifications from the postgres server?
@ 2003-06-17 05:28 weigelt@metux.de
parent: Anagha Joshi <ajoshi@nulinkinc.com>
0 siblings, 1 reply; 10+ messages in thread
From: weigelt@metux.de @ 2003-06-17 05:28 UTC (permalink / raw)
To: pgsql-admin@postgresql.org
On Tue, Jun 17, 2003 at 10:09:04AM +0530, Anagha Joshi wrote:
>
(qestion in subject ...)
yes.
simply execute LISTEN <eventname>; on the one side and then
an NOTIFY <eventname> on the other side. on the next query
you'll see the notify. (you can easily try it w/ pgsql)
but i currently dont know, if you can receive notifies in php ...
that's what i'm really interested in ...
cu
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* Re: Can the frontend get notifications from the postgres
@ 2003-06-17 06:37 A.Bhuvaneswaran <bhuvan@symonds.net>
parent: weigelt@metux.de
0 siblings, 1 reply; 10+ messages in thread
From: A.Bhuvaneswaran @ 2003-06-17 06:37 UTC (permalink / raw)
To: weigelt@metux.de; +Cc: pgsql-admin@postgresql.org
> yes.
> simply execute LISTEN <eventname>; on the one side and then
> an NOTIFY <eventname> on the other side. on the next query
> you'll see the notify. (you can easily try it w/ pgsql)
>
> but i currently dont know, if you can receive notifies in php ...
> that's what i'm really interested in ...
LISTEN/NOTIFY is yet another SQL. We can write a rule on an event and let
it notify. On the other hand, we can have a while(1) process which keeps
listening for that notification ie.. event. Once the event is occured, the
listening process would be notified. The listening process can be any
postgresql client including the one written in C, perl, php, etc.
regards,
bhuvaneswaran
^ permalink raw reply [nested|flat] 10+ messages in thread
* Re: Can the frontend get notifications from the postgres server?
@ 2003-06-17 08:01 weigelt@metux.de
parent: A.Bhuvaneswaran <bhuvan@symonds.net>
0 siblings, 3 replies; 10+ messages in thread
From: weigelt@metux.de @ 2003-06-17 08:01 UTC (permalink / raw)
To: pgsql-admin@postgresql.org
On Tue, Jun 17, 2003 at 12:07:31PM +0530, A.Bhuvaneswaran wrote:
<snip>
> LISTEN/NOTIFY is yet another SQL. We can write a rule on an event and let
> it notify. On the other hand, we can have a while(1) process which keeps
> listening for that notification ie.. event. Once the event is occured, the
> listening process would be notified. The listening process can be any
> postgresql client including the one written in C, perl, php, etc.
But the problem still is: how to receive the NOTIFY from an php script ?
which function of the c-client lib can be used for this ?
cu
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* Re: Can the frontend get notifications from the postgres
@ 2003-06-17 12:08 scott.marlowe <scott.marlowe@ihs.com>
parent: weigelt@metux.de
2 siblings, 1 reply; 10+ messages in thread
From: scott.marlowe @ 2003-06-17 12:08 UTC (permalink / raw)
To: weigelt@metux.de; +Cc: pgsql-admin@postgresql.org
On Tue, 17 Jun 2003 weigelt@metux.de wrote:
> On Tue, Jun 17, 2003 at 12:07:31PM +0530, A.Bhuvaneswaran wrote:
>
> <snip>
> > LISTEN/NOTIFY is yet another SQL. We can write a rule on an event and let
> > it notify. On the other hand, we can have a while(1) process which keeps
> > listening for that notification ie.. event. Once the event is occured, the
> > listening process would be notified. The listening process can be any
> > postgresql client including the one written in C, perl, php, etc.
> But the problem still is: how to receive the NOTIFY from an php script ?
> which function of the c-client lib can be used for this ?
If you're talking about a PHP script running under apache as a module or
CGI, then you probably can't (or if you can, you shouldn't due to time out
issues and such.)
Note that PHP really is a "real programming language", and if you write a
program to execute from the command line and detach it can run in the back
ground like any other language, even starting child processes and having
IPC and all that. Look up the "Process Control Functions" for more on
satrting child processes and all.
Note that the pcntl_* functions are not guaranteed to behave when run
under apache / as a CGI etc...
^ permalink raw reply [nested|flat] 10+ messages in thread
* Re: Can the frontend get notifications from the postgres
@ 2003-06-17 12:27 A.Bhuvaneswaran <bhuvan@symonds.net>
parent: weigelt@metux.de
2 siblings, 1 reply; 10+ messages in thread
From: A.Bhuvaneswaran @ 2003-06-17 12:27 UTC (permalink / raw)
To: weigelt@metux.de; +Cc: pgsql-admin@postgresql.org
> > LISTEN/NOTIFY is yet another SQL. We can write a rule on an event and let
> > it notify. On the other hand, we can have a while(1) process which keeps
> > listening for that notification ie.. event. Once the event is occured, the
> > listening process would be notified. The listening process can be any
> > postgresql client including the one written in C, perl, php, etc.
> But the problem still is: how to receive the NOTIFY from an php script ?
> which function of the c-client lib can be used for this ?
In perl, if i am correct, DBD::Pg does not support it. But, Pg - Perl5
extension for postgresql does it. The functions consumeInput() and
notifies can be used to access the notifyname and pid of backend process.
Refer the man page of Pg module for details.
In C, the functions PQconsumeInput() and PQnotifies can be used to access
the notifyname and pid of backend process. Refer the libpq man page for
details.
In php 4.3.0, the function pg_get_notify() can be used to access the
notifyname and pid of backend process. For details, please refer the below
link:
http://www.science.uva.nl/ict/documentation/php4/function.pg-get-notify.html
Hope it helps.
regards,
bhuvaneswaran
^ permalink raw reply [nested|flat] 10+ messages in thread
* Re: Can the frontend get notifications from the postgres server?
@ 2003-06-17 12:38 weigelt@metux.de
parent: scott.marlowe <scott.marlowe@ihs.com>
0 siblings, 0 replies; 10+ messages in thread
From: weigelt@metux.de @ 2003-06-17 12:38 UTC (permalink / raw)
To: pgsql-admin@postgresql.org
On Tue, Jun 17, 2003 at 06:08:43AM -0600, scott.marlowe wrote:
<snip>
> > But the problem still is: how to receive the NOTIFY from an php script ?
> > which function of the c-client lib can be used for this ?
>
> If you're talking about a PHP script running under apache as a module or
> CGI, then you probably can't (or if you can, you shouldn't due to time out
> issues and such.)
No. The script is running as an standalone process (works as application server).
The Problem is, how to get the NOTIFY message, which is received from the
RDBMS somewhere in the client lib, to the php script.
When using psql, the NOTIFY is displayed after sending an query. It seems
that it is sent within the server's reply to the query. But i dont know
how the clientlib hands it to the application.
cu
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* Re: Can the frontend get notifications from the postgres server?
@ 2003-06-17 12:40 weigelt@metux.de
parent: A.Bhuvaneswaran <bhuvan@symonds.net>
0 siblings, 0 replies; 10+ messages in thread
From: weigelt@metux.de @ 2003-06-17 12:40 UTC (permalink / raw)
To: pgsql-admin@postgresql.org
On Tue, Jun 17, 2003 at 05:57:32PM +0530, A.Bhuvaneswaran wrote:
<snip>
> In php 4.3.0, the function pg_get_notify() can be used to access the
> notifyname and pid of backend process. For details, please refer the below
> link:
aaah. that's what i needed :)
cu
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* Re: Can the frontend get notifications from the postgres server?
@ 2003-06-17 20:37 Jonathan Gardner <jgardner@jonathangardner.net>
parent: weigelt@metux.de
2 siblings, 1 reply; 10+ messages in thread
From: Jonathan Gardner @ 2003-06-17 20:37 UTC (permalink / raw)
To: weigelt@metux.de; pgsql-admin@postgresql.org
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On Tuesday 17 June 2003 01:01, weigelt@metux.de wrote:
> On Tue, Jun 17, 2003 at 12:07:31PM +0530, A.Bhuvaneswaran wrote:
>
> But the problem still is: how to receive the NOTIFY from an php script ?
> which function of the c-client lib can be used for this ?
>
Why in the world would you want to? Think about this for a moment: The script
runs in under a second - why would it want to sit around and wait for a
notification?
- --
Jonathan Gardner <jgardner@jonathangardner.net>
(was jgardn@alumni.washington.edu)
Live Free, Use Linux!
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^ permalink raw reply [nested|flat] 10+ messages in thread
* Re: [ADMIN] Can the frontend get notifications from the postgres server?
@ 2003-06-17 23:34 weigelt@metux.de
parent: Jonathan Gardner <jgardner@jonathangardner.net>
0 siblings, 0 replies; 10+ messages in thread
From: weigelt@metux.de @ 2003-06-17 23:34 UTC (permalink / raw)
To: pgsql-sql
On Tue, Jun 17, 2003 at 01:37:37PM -0700, Jonathan Gardner wrote:
<snip>
> Why in the world would you want to? Think about this for a moment:
> The script runs in under a second - why would it want to sit around
> and wait for a notification?
No, my script runs hours, days, month ...
cu
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end of thread, other threads:[~2003-06-17 23:34 UTC | newest]
Thread overview: 10+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2003-06-17 04:39 Can the frontend get notifications from the postgres server? Anagha Joshi <ajoshi@nulinkinc.com>
2003-06-17 05:28 ` weigelt@metux.de
2003-06-17 06:37 ` Re: Can the frontend get notifications from the postgres A.Bhuvaneswaran <bhuvan@symonds.net>
2003-06-17 08:01 ` weigelt@metux.de
2003-06-17 12:08 ` Re: Can the frontend get notifications from the postgres scott.marlowe <scott.marlowe@ihs.com>
2003-06-17 12:38 ` weigelt@metux.de
2003-06-17 12:27 ` Re: Can the frontend get notifications from the postgres A.Bhuvaneswaran <bhuvan@symonds.net>
2003-06-17 12:40 ` weigelt@metux.de
2003-06-17 20:37 ` Jonathan Gardner <jgardner@jonathangardner.net>
2003-06-17 23:34 ` weigelt@metux.de
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