Maybe you need to think about how you're using Class::DBI. I've been looking at it recently, and my first take is that it makes OOP persistance easy to do at the expense of crippling the database access. It used to be considered a rank newbie mistake to do multiple selects instead of one that uses a table join, but Class::DBI encourages you to do just that. You might want to look into writing some custom queries to dodge around Class::DBI bottlenecks.

I see that dragonchild has already written extensively about this problem:

OO concepts and relational databases.

He doesn't name Class::DBI until late in the article, but Class::DBI definitely falls into the class of things under discussion.