From: | Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> |
---|---|
To: | Mehran Ziadloo <mehran20(at)hotmail(dot)com>, "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: A simple extension immitating pg_notify |
Date: | 2016-07-24 13:35:23 |
Message-ID: | c2e37645-7f6a-b43c-ce60-94e2d04e71b8@aklaver.com |
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Lists: | pgsql-general |
On 07/24/2016 03:31 AM, Mehran Ziadloo wrote:
> I'm sorry, you are right. Let me rephrase that.
>
> What I meant was that the notifications are received by the client
> connections
> as if it was generated within their corresponding database (let's name the
> database with a client connection listening to it; DB_C), then a
> notification
> generated by a NOTIFY command within DB_X like this:
>
> pg_notify_db('DB_C', some_channel, 'payload');
>
> can be heard by the client. Of course, the client needs to know which
> database
> has sent the notification but I think we can skip that part since we can
> easily
> include database name in the notification's payload if necessary.
>
> That was one of the two solutions. The other one is like this:
>
> pg_notify_all(some_channel, 'payload');
>
> And this one sends the notification to all of the client connections,
> regardless of which database they are connected/listening to.
>
> I hope it makes sense now.
>
>
As to how to start writing an extension:
https://www.postgresql.org/docs/9.5/static/extend-extensions.html
As to how NOTIFY/LISTEN works:
--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com
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