This module handles CDBI app's connection type. CDBI makes connection with DBI::connect_cached to decrease connection costs. This is better most of the time. But when you want to use CDBI in mod_perl environment, Maybe you want to use Apache::DBI for persistent connection. Apache::DBI doesn't support connect_cached. As the solution for this problem, you can use this module.
Class::DBI 使用時に DBI の connect_cached メソッド(Class::DBI、というか Class::DBI のスーパークラスである Ima::DBI はその内部で connect_cached を使って DB 接続時のコストを下げている)ではなく Apache::API でコネクションを永続化させたいんだけど! てな時に使うといいらしいです。