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David Janes
davidjanes at blogmatrix.com
Mon Nov 26 15:19:51 EST 2007
Perhaps because of Apache process cycling? Regards, etc... On Nov 26, 2007 3:08 PM, Harish Agarwal <harish at octopart.com> wrote: > Not sure if this helps at all, but I'm noticing that when the problem > appears, it affects all of the incoming requests for a short > duration. The time logged to complete the call to > _apache._global_lock decreases with each subsequent 'hung' request. > > For instance, the last time I noticed a hang in the log files, the > first hang took about 1000 seconds to complete (the hanging is getting > much worse today as traffic has picked up after Thanksgiving), and the > last hang in the 'batch' took about 70 seconds to complete. The log > statements were all printed out at more or less the same time, which > makes me suspect that the requests came in at various points during > the hang, which lasted a total of 1000 seconds, and then the hang was > resolved at the same time for each one, at which point the log > statements were printed. > > I didn't have any problems accessing the site during this period of > time, but that could be because I didn't hit the particular mod_python > interpreter which was hanging. > > > Harish > > > > On Nov 26, 2007, at 11:50 AM, David Janes wrote: > > > I'd be certainly interested in a non-mod_python session handler, since > > I'm suspecting we'll be going to a non-Apache solution soon (since we > > don't really take advantage of any Apache features right now) and we > > were considering writing a generic one -- or adapting mod_python's > > handlers. > > > > On the other hand as Harish notes, it would be good to solve the > > problem for mod_python as mod_python's been very good to us! I'm > > wondering if there's any need at all to touch the Apache global lock > > anyway, or if it can worked around another way. > > > > Regards, etc... > > > > PS: this is what I'm working on right now: > > http://www.onaswarm.com > > > > On Nov 26, 2007 2:21 PM, David Lenwell <dlenwell at gmail.com> wrote: > >> yeah .. its very broken for me too .. What I am working on is my own > >> session handler.. I don't feel that mysql is a valid replacement > >> because it puts unnecessary load on your database server. > >> > >> We are debating on open sourcing the code I am working on. if I win > >> the argument that open source can be good for us then I will > >> contribute my code to the project. > >> > >> > >> > >> On Nov 26, 2007, at 10:55 AM, David Janes wrote: > >> > >>> All I can say is "we too" -- we're using FileSession. We have not > >>> been > >>> able to come up with a cure, though we've minimized use of sessions > >>> which brings the frequency down significantly. > >>> > >>> Regards, etc... > >>> David > >>> > >>> On Nov 26, 2007 1:39 PM, Harish Agarwal <harish at octopart.com> wrote: > >>>> I'm using session handling with ModPython 3.3.1. Originally I was > >>>> using DbmSession and have since transitioned to a custom MySQL > >>>> Session > >>>> handler. With both session types, however, I've noticed that > >>>> session > >>>> initialization intermittently hangs (not forever, but takes as long > >>>> as > >>>> four minutes to complete), at a low-ish (a handful of times every > >>>> hour, while receiving, say, on order of a thousand or so requests > >>>> every hour) frequency which seems to scale with the amount of > >>>> traffic > >>>> we're receiving. I had read that long DbmSession cleanups can > >>>> cause > >>>> problems, which is why I transitioned to the MySQL system, which > >>>> takes > >>>> < 1 second to complete, but I'm still noticing the long session > >>>> init > >>>> times. > >>>> > >>>> > >>>> I put some debugging statements into the code and it seems to be > >>>> related to session locking. In particular, it is this function > >>>> call > >>>> in the lock method of the BaseSession class: > >>>> > >>>> > >>>> _apache._global_lock(self._req.server, self._sid) > >>>> > >>>> > >>>> which is taking some time to complete. I'm not familiar with > >>>> _apache._global_lock (is it used to apply a mutex lock to the > >>>> session?) and am having trouble finding information describing its > >>>> usage - but it seems likely that this is the root cause. In the > >>>> past > >>>> I've had problems with session locking but have since transitioned > >>>> the > >>>> code to ensure that only one session is created per request, as > >>>> such: > >>>> > >>>> if not hasattr(req,'session'): > >>>> req.session = Session.MySQLSession(req) > >>>> > >>>> > >>>> Can anyone tell me if this kind of behavior is normal or is > >>>> indicative > >>>> of some common configuration or coding error? Any help would be > >>>> greatly appreciated. > >>>> > >>>> Thanks, > >>>> -Harish > >>>> _______________________________________________ > >>>> 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 > >>> _______________________________________________ > >>> 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 > > _______________________________________________ > 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
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