I don't have any experience with Trac + MySQL, but this page seems to lay it all out:
http://trac.edgewall.org/wiki/MySqlDb -- You received this message because you are subscribed to the Google Groups "Trac Users" group. To view this discussion on the web visit https://groups.google.com/d/msg/trac-users/-/bdSicJSw2GIJ. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/trac-users?hl=en.
