We were caught in a situation where if we upgraded Postfix, we might break the installed MySQL client. There are a couple of things wrong with this situation. First off, why, oh why, does Postfix require a MySQL client to be installed? Postfix is our MTA, a mail transfer agent, setup because it is easy to configure and we need to do a couple things differently from what is available out of the box. We have absolutely no use for MySQL on every server in the environment. Secondly, why was the third party MySQL (or is that first party, since it is from Oracle?) installed over the default filesystem?