in reply to Singleton Objects for DBI Connection

Firstly, is your Apache just forking processes or does threads? I have no experience with second case.

If Apache just forks, I am mostly sure that Apache children should not share dbhs. But it is very common for mod_perl applications to keep dbh till the child lives, especially with Oracle (Oracle does not dedicate one db process for one connection necessarily). Simply, 1 Apache child == 1 dbh.