Making new connections is expensive, but connection pooling is not the only alternative. The Apache::DBI module keeps connections open so that you don't need to re-connect. It is not "pooling" because the connections are not shared -- each process opens a connection and keeps it open.

This will change with the thread support in mod_perl 2 and a future release of DBI which will include direct support for connection pooling. In the meantime, what Apache::DBI does is fine for most sites.