Update: + There seems to be no web2py error. Thus, no traceback.
+ I don't remember if I got this error Premature end of script headers: wsgihandler.py ) with sqlite, but having just tested again with sqlite, I didn't get this error. At the moment, this error only occurred with postgres (8.6.3 as I'm on Debian Lenny). + This error occurred sporadically. Testing with ab ranging from 50 to 200 concurrent connections, I couldn't always duplicate the error. Sometimes, it occurred. Sometimes, it didn't. PS: Someone asked about apache bench. It's included in apache2-utils (which can be installed by apt). Pretty easy to use. I used this: ab -kc 200 -t 10 http://yourdomain.com/ to open 200 concurrent requests in 10 seconds. On Jan 11, 8:58 am, Massimo Di Pierro <massimo.dipie...@gmail.com> wrote: > Can I see the error? Is there a traceback? Is the db server on the > machine? > > Massimo > > On Jan 9, 11:30 am, VP <vtp2...@gmail.com> wrote: > > > It is indeed the case that there was a segmentation fault, reported in > > apache error log. > > > Perhaps, it's not clear, but this problem occurs under posgres under > > debian lenny, not sqlite. I am not running web2py as a CGI script. I > > am using the web2py deployment script (for setting up apache and > > web2py): > > > <VirtualHost *:80> > > WSGIDaemonProcess web2py user=myusername group=myusername \ > > display-name=%{GROUP} > > WSGIProcessGroup web2py > > WSGIScriptAlias / /home/myusername/web2py/wsgihandler.py > > > .... > > > On Jan 8, 9:59 pm, Graham Dumpleton <graham.dumple...@gmail.com> > > wrote: > > > > You were possibly using a an old version of sqlite which isn't safe to use > > > in a multithreaded configuration. > > > > The MPM settings are not going to help in this case as that error could > > > only > > > come about because you are using mod_wsgi daemon mode and so application > > > is > > > running in distinct process and not those affected by the MPM or its > > > settings. > > > > The only other way you could get that error is that you are actually > > > running > > > web2py as a CGI script. > > > > Overall, that specific error message means your daemon mode process that > > > is > > > running web2py crashed. You would likely find that there is a segmentation > > > fault messages in main Apache error log as well at that time. > > > > Crashing could be because of sqlite thread problems, but could also be > > > because you are forcing web2py to run in main interpreter of daemon > > > processes and at the same time are using a third party C extension module > > > for Python that is not safe for use in sub interpreters. > > > > So, ensure sqlite is up to date. And ensure that you have: > > > > WSGIApplicationGroup %{GLOBAL} > > > > in configuration to force use of main interpreter. > > > > Graham > > > > On Sunday, January 9, 2011 6:44:14 AM UTC+11, VP wrote: > > > > > We occasionally got an Apache error so the page didn't get displayed. > > > > So I decided to stress test using Apache Bench (ab). It seems the > > > > site suffered failure up to 50-100 concurrent connection. > > > > > Apache error log showed this error: > > > > > >>>>>>Premature end of script headers: wsgihandler.py > > > > > After digging around, I found similar discussions and change > > > > apache2.conf like this: > > > > > # prefork MPM > > > > StartServers 5 > > > > MinSpareServers 5 > > > > MaxSpareServers 10 > > > > MaxClients 256 > > > > MaxRequestsPerChild 500 > > > > ServerLimit 256 > > > > > Didn't seem to help. > > > > > ==== > > > > > A few notes: > > > > > + It appears when I switched to sqlite instead of posgres, I didn't > > > > have the problem. (Sqlite had other problems, such as occasional > > > > database locking, which is more serious) > > > > > + I am on a VPS with 768MB with 1GB burstable. While I'm doing the > > > > stress test with Apache Bench (ab), using free on the server revealed > > > > memory usage was about 450MB. (Which is a lot, but is still under > > > > limit). > > > > > ===== > > > > > In summary, memory was available. But we got this wsgi error in > > > > Apache with multiple requests. > > > > > Any idea please? > > > > > Thanks. > >
