Today’s lesson is manyfold:

1. Devel::Size is your friend;
2. Maintaining state across runs of a program is good unless said state is able to keep getting bigger because of circumstances beyond your control;
3. In which case it is a very good idea to keep checking it for size and pruning it whenever you have to…
4. Especially if you launch many many copies of said program in parallel.

Got all that? Good! :-)