On Tue, Sep 22, 2009 at 12:46 PM, Henning Westerholt <henning.westerholt@1und1.de> wrote:

On Dienstag, 22. September 2009, Jason Penton wrote:
> Hi Andrei,
>
> From what I have seen in the code this is pretty useless (no offence).
>
> The ping in this particular instance is only executed JUST before a real
> query is to be issued. i.e. if a query is not used in Kamailio for a couple
> of hours - the ping is actually never sent...........

Hi Jason,

you're right that its not executed with a timer or similar, but the mysql_ping() should reconnect to the database if the auto reconnect is activated, according the documentation:

http://dev.mysql.com/doc/refman/5.0/en/mysql-ping.html

Actually the reconnect doesnt work if your firewall has torn down the connection. You can try this with other mysql clients like - the usual client, toad, etc. Leave your connection idle for about 45 mins and you will see that there's nothing you can do to reconnect.

I have tested this extensively and can only imageine that because the firewall has closed the connection, the reconnect in mysql doesnt work - because the socket has been torn down underneath mysql (at the OS level). So effectively you see a hangin process in Kamailio up to 5 minutes :) which is REALLLLLLLLY bad :D

Ok so I am going to go ahead with using a timer to ping the mysql cons in the db_pool. Everyone happy with that?

Cheers
Jason

> what I have noticed is that when the connection is torn down by the
> firewall, the ping actually hangs (reconnect fails), etc
>
> So, we NEED a proper ping (keepalive) functionality :D

This could be implemented with help of the internal timers, just execute periodically the mysql_ping command, for example.

Henning