FWIW, thread on mod_wsgi list about this is at: http://groups.google.com/group/modwsgi/browse_frm/thread/c6e65603c8e75a30
Graham On Jan 15, 4:10 am, "Michael Bayer" <mike...@zzzcomputing.com> wrote: > Damian wrote: > > Hi, > > > Every few days, when we experience higher loads we get sqlalchemy's > > > TimeoutError: QueuePool limit of size 5 overflow 10 reached, > > connection timed out, timeout 30 > > > Along with that I see an increase in (2-3 a minute): > > > (104)Connection reset by peer: core_output_filter: writing data to the > > network > > > and > > > (32)Broken pipe: core_output_filter: writing data to the network > > > in my apache error logs. > > > Having checked over my pylons code a few times, the Session.remove() > > should always be called. I'm worried that the broken pipe or > > connection reset by peer mean that remove isn't being called. > > sounds more like the higher load means more concurrent DB activity, PG > then takes more time to return results, more reqs then come in, > connections aren't available since they're all busy. AFAIK the broken > pipe stuff doesn't kill off the Python threads in the middle of their > work...if they threw an exception, hopefully you have Session.remove() > happening within a finally:. Since you're on PG, just to a "ps" listing > on your database machine or better yet use "pgtop" and you'll see just > what happens when a spike comes in. > > > > > > > The server is runningmod_wsgiwith apaches mpm_worker with the > > following config: > > > <IfModule mpm_worker_module> > > StartServers 16 > > MaxClients 480 > > MinSpareThreads 50 > > MaxSpareThreads 300 > > ThreadsPerChild 30 > > MaxRequestsPerChild 0 > > </IfModule> > > > and usingmod_wsgi'sdaemon mode: > > > WSGIDaemonProcess somename user=www-data group=www-data processes=4 > > threads=32 > > > Is this somehow overkill? The server is a well speced quad core with > > 8 gigs of ram and fast hard drives. > > > It also runs the database server (postgres). > > > Has anyone else experienced this kind of problem? I've cross posted > > this to both themod_wsgiand sqlalchemy mailing lists - hope that's > > ok as I believe this may be relevant to both groups. > > > Thanks, > > Damian > > -- > > You received this message because you are subscribed to the Google Groups > > "sqlalchemy" group. > > To post to this group, send email to sqlalch...@googlegroups.com. > > To unsubscribe from this group, send email to > > sqlalchemy+unsubscr...@googlegroups.com. > > For more options, visit this group at > >http://groups.google.com/group/sqlalchemy?hl=en.
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