Graham, welcome. Careful, though -- we might
convert<http://twitter.com/GrahamDumpleton/status/23120780938190848>you. ;-)
http://twitter.com/GrahamDumpleton/status/23120780938190848
On Saturday, January 8, 2011 10:59:37 PM UTC-5, Graham Dumpleton 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.
>>
>>
