Diagnosing memory usage

[Michael Gardner]

I've inherited an existing Apache+mod_perl 1.3.x server. I am not very  
experienced with Apache nor mod_perl, so I have to pick up things as I  
go along.

Recently I built a new version of Apache (1.3.41) with static mod_perl  
1.30, and it seems to work. The problem is that every few days or so,  
the server apparently runs out of memory, grinding to a halt and  
necessitating a hard reset.

I suspect mod_perl is the primary memory user here, since most of the  
pages we serve are Perl scripts. But I don't know how to go about  
diagnosing the problem, especially since the server gets so bogged  
down when it happens that I can't access it to get info on running  
processes, memory usage, etc. I have noticed that the memory usage of  
each httpd process seems to grow over time, but it's usually very slow  
growth, and I can't tell if that's really a leak or just normal  
behavior.

Workarounds would be helpful, but naturally I'd prefer to eliminate  
the cause of the problem. I've been looking through the documentation,  
but haven't made much progress so far. How can I get to the bottom of  
this?

-Michael