I'm not proposing to allow my clients to see my memory addresses, it's a purely internal thing. I think I'm just stupid for not deciding to just use a unique ID on each row of data =)
Interesting that under mod_perl it's persistant and the memory addresses stay. Seems like it would be a poor idea to write scripts to depend on that, though, no? What if someone tries to run your script on a non mod_perl/non persistent environment?