Lua Auth

Just happened to be surfing the docs and saw this. This is beyond awesome:

https://wiki2.dovecot.org/AuthDatabase/Lua

Any words of wisdom on using it? I'd be putting a bunch of mysql logic in it. Any horrible gotchas there? When it says 'blocking', should I assume that means that a auth worker process will *not* accept any new auth lookups until both auth_passdb_lookup() and auth_userdb_lookup() have completed (in which I'd be doing several mysql calls)? If that's the case, I assume that the number of auth workers should be bumped up.

And is a 2.3 release fairly imminent?