Re: Listen and Notify - Mailing list pgsql-general

From Alexander Reichstadt
Subject Re: Listen and Notify
Date
Msg-id A7EC8171-58DD-490A-8ACC-E14393ADB188@mac.com
Whole thread Raw
In response to Re: Listen and Notify  (Mark Morgan Lloyd <markMLl.pgsql-general@telemetry.co.uk>)
List pgsql-general
The framework I am using is PGSQLKit for Mac OS X for which the source was available and which I downloaded and altered
since.Actually it gives you access down to the pqlib calls. 

The connection being closed was one of the issues. I had added convenience classes with class methods to the framework.
Theconnection was kept in the background with its credentials and settings in place, but only opened on a per-request
basisand closed afterwards which I changed now and now it works. 

As to mixed case, no, it was all lower case, but using terminal for verification I had taken this into consideration so
forlistener and notifier to match. 

Am 01.05.2012 um 14:51 schrieb Mark Morgan Lloyd:

> Merlin Moncure wrote:
>> On Mon, Apr 30, 2012 at 1:47 AM, Alexander Reichstadt <lxr@mac.com> wrote:
>>> Hi,
>>>
>>> From the documentation I was able to build a trigger firing upon deletion of a record a function that delivers
tablename_operationas a notification one needs to subscribe to. So in terminal I can say LISTEN persons_delete and
instantlywill receive 
>>>
>>>       Asynchronous notification "persons_delete" received from server process with PID 54790.
>>>
>>> if there was a delete. But what I don't fully understand is how to do this with PQnotifies. Following the docu I
getno notifications even though I subscribe to them after successfully connecting to the server the same way I do using
terminal.
>>>
>>> Googling didn't give me examples I was able to use. Please, can someone help?
>> I'm suspecting operator error because using PQnotifies is exactly what
>> psql does.  Maybe you could post a small test program?  Are you using
>> a mixed case notification name?
>
> Works here in a Pascal program built using Lazarus. You /must/ however, ensure that the session requesting the
notificationis kept active and is the one that's regularly checked, it's easy to lose track of this in a development
frameworkwhich isolates you from the low-level handles etc. 
>
> --
> Mark Morgan Lloyd
> markMLl .AT. telemetry.co .DOT. uk
>
> [Opinions above are the author's, not those of his employers or colleagues]
>
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