[sr-dev] git:master: modules_k/presence Fixed DB Storage Modes

[Anca Vamanu]

Hi Klaus,


On 02/20/2012 10:54 AM, Klaus Darilion wrote:
> Hi Anca!
>
> I wonder what happens if I build a server cluster (p1 and p2) with
> subs_db_mode=3 and publ_cache=0.
>
> Then a subscription to user1 is received from p1 and stored into the DB.
> Then user1 sends a publish via p2, which is stored in the DB.
>
> Who will send the NOTIFY for the subscription? p1 or p2? I guess p2 as
> p1 has no idea about the publish - correct?
The machine that received the Publish, in this case p2 will send the 
Notify. Looking now in the code, I saw that when sending out this 
Notify, p2 will actually put in the Contact header the contact of the p1 
(initial contact). I don't think there should be any problem with this ( 
except someone compares Via and Contact, but probably not). In this way 
always the reSubscribes will get to the same machine.
I see now an opportunity to improve the performance because of this 
behavior - having a mode in which to read from memory for Subscribes, 
but always read from DB for Publishes.

Regards,
Anca

> thanks
> Klaus