Re: Mysql with short wait_timeout

On Tue, Jul 28, 2009 at 3:19 AM, Guillaume Cottenceau <[email protected]> wrote:

> <snip>

>
> However, crashing Kannel on database unavailability (e.g. more
> precisely than just not being able to store the DLR on random db
> error) is of course not good and this should probably be fixed
> (can you contribute that?).
>

Well a contribution is probably the plan here :)


>
> That said, if your database runs out of available connections,
> then you're really in trouble. I doubt only Kannel will have a
> problem on that (I mean, in the best case then you're unable to
> service your clients anyway, in the worst case other applications
> will crash as well - so really you want to implement something to
> prevent from opening that many connections, some kind of requests
> queueing etc).
>


While I agree here, Kannel works in a "permanent" state where the rest if
the connections here is are from php application with apache with many
threads that creates connections whenever it's needed. The apps consume
100-150 connections normally, and kannel 1. In this specific case, an
incorrect query cause the connections to jumps to 600, maxing the database.
Anyway, I have no trouble "reserving" this connections for kannel and keep
it opened. The rest of the applications can somewhat degraded if connections
to the database aren't available...


> > 2 - Send a set wait_timeout on connection to override the value from
> MySQL,
> > however in this case I don't know what we should set it to since the
> mysql_ping
> > is based on activity... (Maybe 8h ? since it's the default MySQL value)
>
> And what if you have no Kannel activity for 8 hours? In the
> mentioned doc it's not very clear if that can be deactivated,
> which may be a solution.


Yes, you can set it to 0 to deactivate it.


>
>
> Disclaimer: I'm not a heavy pgsql user, very little experience
> with mysql.
>
> --
> Guillaume Cottenceau
>

Well that's good, other experiences leads to different views, which is what
I was looking for by posting here :)

-- 
Math
aka ROunofF

[email protected]