See Mini-Tutorial: Perl's Memory Management, Efficient way to handle huge number of records? ( esp Re: Efficient way to handle huge number of records? ), What could cause excessive page faults? (esp Re: What could cause excessive page faults? (A fix)), Out of Memory selecting from MySQL, sorting very large text files (esp Re: sorting very large text files )

The general tips are , estimate the max memory you can pre-size/pre-allocate without going into swapping, and then don't exceed that size (so you don't go into swapping)

And buy more memory :) maybe even solid-state-disks, apparently they're cheaper/faster these days

But thats just what I read, its mostly true :)