in reply to Disk based hash (as opposed to RAM based)
After asking myself a series of questions about how best to do this, I believe that the best way is to load everything into a temporary database table and use the database to process all this data. I would love to use perls hashes (which is initially why I chose perl) but this approach should be the best I can come up with. I will post the code once I finish it.
I am rolling my own code on this one and am not using an API or other library of code other than perl and MySQL.
My thought is to load the data, and use a combination of mysqls left, substr, and other string functions to populate data in a second column with the values I would use as a key. The MySQL select...where should let me then retrieve data in a way that mirrors perls way of getting values from a hash by key. Does that make sense? I will post code later.