Can you comment on memory usage? I have see this once: "after a while web serving slows" it appeared to be due to a memory leak somewhere (did not experience it with web2py+Rocket but only in web2py+mod_wsgi+apache).
I googled it and I found Django was having the same problem on some hosts: http://stackoverflow.com/questions/2293333/django-memory-usage-going-up-with-every-request http://blog.webfaction.com/tips-to-keep-your-django-mod-python-memory-usage-down I followed the advice from a comment in the last post to limit the number of requests served by each process: # prefork MPM StartServers 5 MinSpareServers 5 MaxSpareServers 10 MaxClients 256 MaxRequestsPerChild 500 ServerLimit 30 instead of the default: # prefork MPM StartServers 5 MinSpareServers 5 MaxSpareServers 10 MaxClients 256 The problem disappeared. The exact values that fix the problem may depend on the ram available. Massimo On Jul 20, 4:30 pm, Michael Toomim <too...@gmail.com> wrote: > Let me also summarize the issues so far. > > Originally: > - I got three types of error messages in apache logs > - Logging messages were often duplicated 2, 3, 5 times > - I got the IOError ticket a few times > - After a while the web serving slowed (some requests took up to a > minute) and then quit completely > > After rebooting: > - I get one type of error message in apache logs, in big batches > - I get the IOError ticket once or twice > - After a while web serving slows (sometimes 150s per request) and > stops > > So I haven't been seeing the duplicate log messages anymore. > > I upgraded to a bigger machine and am changing my code to remove ajax > (will reduce load by 60x by decreasing functionality). I don't know > what else to do. > > On Jul 20, 2:03 am, mdipierro <mdipie...@cs.depaul.edu> wrote: > > > Thanks for the clarification. > > > @Michael, do you use the logging module? How? > > > On Jul 20, 4:00 am, Graham Dumpleton <graham.dumple...@gmail.com> > > wrote: > > > > On Jul 20, 5:17 pm, mdipierro <mdipie...@cs.depaul.edu> wrote: > > > > > The problem with IOError, I can understand. As Graham says, if the > > > > client closes the connection before the server responds or if the > > > > server timesout the socket is closed and apache logs the IOError. > > > > That isn't what I said. If you see that message when using daemon > > > mode, the Apache server process that is proxying to the daemon process > > > is crashing. This is different to the HTTP client closing the > > > connection. You would only see that message if HTTP client closed > > > connection if using embedded mode. > > > > I know they are using daemon mode as that is the only situation where > > > they could also see the message about premature end of script headers. > > > > > What I really do not understand is why some requests are handled by > > > > multiple threads. web2py is agnostic to this (unless you use Rocket > > > > which you do not). web2py only provides a wsgi application which is > > > > executed - per thread - by the web server. It is the web server (in > > > > your case apache) that spans the thread, maps requests to threads, > > > > calls the web2py wsgi application for each of them. > > > > > If this is happening it is a problem with apache or with mod_wsgi. > > > > More likely the problem is that they are registering the logging > > > module from multiple places and that is why logging is displayed more > > > than once. They should log the thread ID as well as that would confirm > > > whether actually from the same thread where logging module handler has > > > been registered multiple times. > > > > Multiple registrations of logging handler could occur if it isn't done > > > in a thread safe why, ie., so as to avoid multiple threads doing it at > > > the same time. > > > > Graham > > > > > Can > > > > you tell us more about the version of ubuntu, apache and mod_wsgi that > > > > you are using? Any additional information will be very useful. > > > > > Massimo > > > > > On Jul 19, 9:01 pm, Michael Toomim <too...@gmail.com> wrote: > > > > > > I'm getting errors like these in my apache error logs: > > > > > > [Mon Jul 19 18:55:20 2010] [error] [client 65.35.93.74] Premature end > > > > > of script headers: wsgihandler.py, > > > > > referer:http://yuno.us/init/hits/hit?assignmentId=1A7KADKCHTB1IJS3Z5CR16OZM4V... > > > > > [Mon Jul 19 18:55:20 2010] [error] [client 143.166.226.43] Premature > > > > > end of script headers: wsgihandler.py, > > > > > referer:http://yuno.us/init/hits/hit?assignmentId=1A9FV5YBGVV54NALMIRILFKHPT1... > > > > > [Mon Jul 19 18:55:50 2010] [error] [client 117.204.99.178] mod_wsgi > > > > > (pid=7730): Exception occurred processing WSGI script '/home/toomim/ > > > > > projects/utility/web2py/wsgihandler.py'. > > > > > [Mon Jul 19 18:55:50 2010] [error] [client 117.201.42.84] mod_wsgi > > > > > (pid=7730): Exception occurred processing WSGI script '/home/toomim/ > > > > > projects/utility/web2py/wsgihandler.py'. > > > > > [Mon Jul 19 18:55:50 2010] [error] [client 117.201.42.84] mod_wsgi > > > > > (pid=7730): Exception occurred processing WSGI script '/home/toomim/ > > > > > projects/utility/web2py/wsgihandler.py'. > > > > > [Mon Jul 19 18:55:50 2010] [error] [client 117.201.42.84] IOError: > > > > > failed to write data > > > > > [Mon Jul 19 18:55:50 2010] [error] [client 117.201.42.84] mod_wsgi > > > > > (pid=7730): Exception occurred processing WSGI script '/home/toomim/ > > > > > projects/utility/web2py/wsgihandler.py'. > > > > > [Mon Jul 19 18:55:50 2010] [error] [client 117.201.42.84] IOError: > > > > > failed to write data > > > > > [Mon Jul 19 18:55:50 2010] [error] [client 117.201.42.84] mod_wsgi > > > > > (pid=7730): Exception occurred processing WSGI script '/home/toomim/ > > > > > projects/utility/web2py/wsgihandler.py'. > > > > > [Mon Jul 19 18:55:50 2010] [error] [client 117.201.42.84] IOError: > > > > > failed to write data > > > > > [Mon Jul 19 18:55:50 2010] [error] [client 117.201.42.84] mod_wsgi > > > > > (pid=7730): Exception occurred processing WSGI script '/home/toomim/ > > > > > projects/utility/web2py/wsgihandler.py'. > > > > > [Mon Jul 19 18:55:50 2010] [error] [client 117.201.42.84] IOError: > > > > > failed to write data > > > > > > My web app gets about 7 requests per second. At first, things work > > > > > fine. Then after a while it seems like every request gets handled by > > > > > MULTIPLE threads, because my logging.debug() statements print multiple > > > > > copies of each message and it seems my database gets multiple entries. > > > > > And I get these errors in the apache logs (with LogLevel debug). > > > > > > Any idea what to do? Where to look? I'm on ubuntu.
