[mod_python] Issues in apache MPM mode

Arzola, Nelson narzola at seattleschools.org
Mon Aug 22 13:36:54 EDT 2005

My understanding is that mod_python actually starts a unique interpreter for each thread.  If you read the message in your log file carefully, it says "(Re)Importing".  You can verify that this is the case by starting the httpd process with -X flag (one process, one thread, do not detach from console).  You should only see one "(Re)Importing" message.

-----Original Message-----
From: mod_python-bounces at modpython.org [mailto:mod_python-bounces at modpython.org] On Behalf Of Sébastien Arnaud
Sent: Monday, August 22, 2005 6:31 AM
To: mod_python at modpython.org
Subject: [mod_python] Issues in apache MPM mode


I have developed over time a small web application framework over  
mod_python, in order to help me write applications quickly and  
cleanly. I do intend to release it open source once I clean it up a  
little bit.

I wrote it with in mind targeting apache MPM (worker threaded), which  
seemed to me the best mode in apache to lead to high performance.  
Unfortunately, I am discovering that modules are getting reimported  
over and over in this mode, and this is causing apache processes/ 
threads to eventually exit with a segmentation fault :(
FYI the web application framework is Web Object Oriented (meaning  
that you map a python class to a url and view), and each page class  
is registered has a child of main site class, which is then assigned  
into a site pool. This leads to quite some memory utilization, but is  
VERY fast in terms of execution.

I saw that Graham had wrote a few patches to avoid those problems. Is  
there any hope to see those checked in mod_python source code any  
time soon? For the long term, can we expect to have a flawless  
mod_python behavior in threaded mode? or do we have to be like the  
mod_php folks and target only apache PREFORK mode?

I just need to know so that I can rewrite/adapt my framework if MPM  
is not going to be fixed for a while.



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