memory issues when running with mod_perl

Someone posted an issue to the mod-perl list a few weeks ago about
their machine losing a ton of memory under a mod-perl2/apache/
postgres system - and only being able to reclaim it from reboots

A few weeks later I ran into some memory related problems, and
noticed a similar issue. Starting / stopping the clients had no
effect on memory (which was expected... the new ones just pulled in
from the shared cache )

But stopping the daemon didn't affect memory either. running ipcs, i
saw the shared memory lock freed. but the kernel never seemed to get
it back. and then I'd run into swap.

I felt this on freebsd 6.x + pg 8.1.x , seperate people on the list
had it under the 2.4 / 2.6 kernels with 7.x and 8.x pgs.

someone just posted that they have the same issue on one machine
under 7.4.9, but not (yet) under 7.4.13

does anyone have some suggestions on how to test this to make sure
its a pg issue ? it often takes a few days for pg to consume enough
memory for this behavior to set in place.