Re: Listen / Notify rewrite

Joachim Wieland wrote:
> On Thu, Nov 12, 2009 at 1:04 AM, Andrew Chernow <ac@esilo.com> wrote:
>> I think a bsearch would be needed.  Very busy servers that make heavy use of
>> notifies would be quite a penalty.
> 
> In such an environment, how many relations/channels is a backend
> typically listening to?
> Do you have average / maximal numbers?
> 

We have a system where many libpq clients, ~2000 - 4000 per server (depends on 
hardware), maintain a persistent backend connection.  Each connection listens 
for notifies, LISTEN 'client_xxx'.  There are maybe 10 different reasons why a 
NOTIFY 'client_xxx' is fired.  Sometimes, notifies are broadcasted to all client 
connections, or just portions of them.

The goal is real-time messaging to a large groups of computers/devices.  Past 
4000, the problem is distributed to a second, third, etc... server.

-- 
Andrew Chernow
eSilo, LLC
every bit counts
http://www.esilo.com/