[mod_python] Mod_Python not releasing memory?

I have Apache/2.2.8 (Unix) mod_python/3.3.1 Python/2.4.5 on Red Hat Enterprise Linux AS release 4 (Nahant Update 6).
Apache compiled:
./configure --with-mpm=prefork --enable-mods-shared="most proxy charset_lite" --with-expat=system 

Mod Python:
./configure --with-apxs=/usr/local/apache2/bin/apxs --with-python=/usr/local/bin/python2.4 

Python:
./configure --enable-shared 

My application is using Cheetah to generate a very large HTML table and sending it back to the client, after retrieving a bunch of database rows.

One hit to Apache to generate one of these big tables runs memory usage up to 30.6% of system RAM:

$ ps aux | grep 30316 | grep -v grep
USER       PID %CPU %MEM   VSZ  RSS TTY      STAT START   TIME COMMAND
web      30316  2.7 27.7 1559948 1122772 ?   Rl   12:48   1:21 /usr/local/apache2/bin/httpd -k start

$ ps aux | grep 30316 | grep -v grep
USER       PID %CPU %MEM   VSZ  RSS TTY      STAT START   TIME COMMAND
web      30316  2.7 30.6 1559948 1237948 ?   Rl   12:48   1:21 /usr/local/apache2/bin/httpd -k start

After the query is done and the results delivered to the browser, the Apache process is still holding about 25% of system memory.
I don't see any way to free that memory.  
Once I "return result" to the browser, I can't do "result=None" so I'm relying on Python to release the memory and it is taking way too long for that to happen.  I do set the database result set to None as soon as I can and that helps some.

If I get a number of these big hits, OOM starts killing PIDs which is a "Bad Thing".

Any clues on how to make that memory release sooner?

Thanks,
Scott


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