could this be a timeout issue? Could it be the app causes a deadlock in the db? What app is this?
On Jan 11, 10:58 am, Kenneth Lundström <kenneth.t.lundst...@gmail.com> wrote: > I'm getting the same Premature end of script on a CentOS 5.?, MySQL, WSGI and > Apache. > > Never done any stresstests, I'll try later to day. > > Kenneth > > ----- Ursprungsmeddelande ----- > > > > > > > > > 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 10http://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.
