[mod_python] Session Hanging Problems

(1)
We've had no problems so far, but I'd like to keep it in for awhile to
see if any problems occur before staking my reputation on it ;-)

Note that it's running on 3 sites:
http://www.blogmatrix.com
http://www.onaswarm.com
http://www.onamine.com

(2)
In terms of the locking logic, we just override all the lock functions
and implement them exactly the same way the base classes do (see
earlier code sample). Note that we _always_ explicitly unlock our
sessions, just because.

(3)
Definitely a Linux solution, though perhaps something like this would work:

if os.flock:
 ... do flock stuff ...
else:
  super.original_lock_code(self, ...)

Regards, etc...

On Dec 4, 2007 12:28 PM, Harish Agarwal <harish at octopart.com> wrote:
> Have you noticed any performance issues?  I want to make sure to keep
> things fast and am worried that departing from the Apache lock system
> will degrade performance.  Why was mod python designed to use the
> apache system and not use session specific locks?
>
> Also a note for the list - I'm now explicitly unlocking the session
> after each save to ensure that the session isn't locked during a
> req.write call.  I've seen one hang since then, but in twelve hours,
> that is much much better than the issues I was seeing before.
>
> I think that this problem directly contradicts the general philosophy
> behind using the mod_python session handling scheme - I feel like I've
> read, a few times now, that there is no reason to have to explicitly
> unlock sessions, but this is an instance where running everything in
> its default configuration (not unlocking sessions, flushing the buffer
> on req.writes) causes serious hanging problems...  In addition,
> unlocking the session after each save doesn't sit well with me - I
> don't think the session is thread-safe now (given that there can be
> multiple save's per request).
>
> -Harish
>
>
>
> On Dec 4, 2007, at 1:48 AM, David Janes wrote:
>
> > I'll note for the list that I put in the changes I outlined above ---
> > that is, handled locking entirely ourselves rather than using Apache's
> > lock function -- and I haven't had a hang since.
> >
> > Regards, etc...
> >
> > --
> > David Janes
> > Founder, BlogMatrix
> > http://www.blogmatrix.com
> > http://blogmatrix.blogmatrix.com
>
> > _______________________________________________
> > Mod_python mailing list
> > Mod_python at modpython.org
> > http://mailman.modpython.org/mailman/listinfo/mod_python
>
>



-- 
David Janes
Founder, BlogMatrix
http://www.blogmatrix.com
http://blogmatrix.blogmatrix.com