At the mega-corp where I work, the administrators have mechanisms to provide different versions of Perl ( & Vi & Emacs & Informix & Sybase & .... ). Last year they stopped supporting Per 5.005. Modules are available in multiple versions, and a special versioning feature is used prior to the 'use' statements to specify which version of a module to use.

That makes it the responsability of the programmer to update script X from Perl5.6 to Perl5.8, or to move from one version of DBI to a more recent one. There's no reason for my monitoring script requirements to affect the performance of your data loading script.

Just this week I am migrating a set of scripts from 5.6 to 5.8. I didn't want the bother, until now, but a bug has appeared which makes the migration necessary.