Re: notification information functions

Hannu Krosing wrote:
> On Sun, 2008-05-18 at 16:00 -0400, Andrew Dunstan wrote:
>   
>> I am working on moving the notification buffer into shared memory as 
>> previously discussed. Since pg_listener will no longer exist, I think we 
>> need to provide a couple of information functions.
>>
>> I suggest:
>>
>> pg_listened_events(out event name) returns setof record
>> pg_pending_events(out  event name, out message text) returns setof record
>>
>> The first would show events being listened on by the current backend, 
>> while the second would show all pending events for the current db.
>>
>> Given that there will no longer be any central place where events will 
>> be registered to be listened on, it will not be possible to show all 
>> such events for the  current db.
>>     
>
> Are you sure that there will be no central place ? 
>
> How will we know then that all listeners have received their events ?
>   

Yes, quite sure. See Tom's answer to more or less this question from a 
year ago:

http://archives.postgresql.org/pgsql-hackers/2007-03/msg01570.php

What we will have in shared memory is each backend's queue pointer (if any).

cheers

andrew