Forking after using the array (regardless whether you undef it first) only makes the problem worse, now you have doubled the memory usage. Letting the parent die just makes you back at the previous memory usage.

There is a "famous" trick, used by long running processes to prevent possible memory leakage from sucking up all the resources, but that doesn't use fork, it uses exec. execing yourself means that you are restarting yourself - starting with a fresh sheet of memory. Obviously, this is not going to work for many programs.

Abigail