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.

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