Marcus Ramberg wrote in the December 2014 Perl Advent Calendar about Mojo::Pg, the new DBI wrapper for the Mojolicious framework.
Particularly of interest are
Automatic transaction rollback if the 'guard variable' goes out of scope. In practice this means if you just return or throw an exception in the middle of a routine, any transactions get rolled back without having to do anything yourself.
Migrations. Written in plain SQL and easily embedded or attached to your program, this was one of the few things I liked about Rails, but it's here now.
Asynchronous triggers. You could have two processes attached to the same database; when one does an INSERT, the other process gets a notification. This opens up all kinds of things that were nearly impossible before.
On top of the upcoming "INSERT … ON CONFLICT …" grammar in Postgres 9.5, which lets you do things like:
INSERT INTO distributors (did, dname) VALUES (5, 'Gizmo transglobal'), (6, 'Associated Computing, inc') ON CONFLICT (did) DO UPDATE SET dname = EXCLUDED.dname;
it's well worth considering whether to keep using MySQL at all.