Without trying to derail this thread (which is more to do with CGI versus mod_perl rather than MySQL), you still haven't really explained why he should also switch to postgres. Is there a specific reason why he shouldn't continue on using MySQL, even with mod_perl (assuming he had the option)?
Comment on Re: Re: Re: Re: What if mod_perl is not an option?
No, there is no reason for _must_ use postgres, MySQL is also a database. But in my opinion postgres is much richer and robust than MySQL. Now as the question is CGI/Mod_perl with mysql why not get familar with the very good database postgres? That saves that switch next year.