[Dovecot] Dovecot 2 and expire

[Brandon Lamb]

expire_dict = proxy::expire

I found this expire_dict somewhere, might have been the 1.x wiki, but
on the expire plugin page there is no mention of it. I am trying to
troubleshoot why my mysql table has no entries. Do I need this line?
Is that correct for using mysql?

In dict {} I have

expire = mysql:/etc/dovecot/conf.d/dovecot-dict-expire.conf.ext

and in plugin {} i have

expire_dict = proxy::expire
expire = Trash 30d
expire2 = Trash/* 30d
expire3 = Spam 14d
expire4 = Spam/Removed 6h
expire5 = Spam/Delivered 2d
expire6 = Deleted* 30d
expire7 = Archive 30d

Contents of dovecot-dict-expire.conf.ext

connect = host=servername dbname=mail user=un password=pw

map {
	pattern = shared/expire/$user/$mailbox
	table = expires
	value_field = ts_expires

	fields {
		username = $user
		mailbox = $mailbox
	}
}

I must admit I dont understand what pattern means, I just copied from
something when I was setting this up.