Angharad:

With that much data, I'd suggest putting it in a DBM file (AnyDBM_File or similar) or a database (DBI with DBD::SQLite) would give you a couple of advantages:

• You wouldn't have to keep all that data in memory
• You'd only have to load data into the database when it changes
• You'd still get quick lookup on your data

...roboticus

When your only tool is a hammer, all problems look like your thumb.