[cebka]

They are not related at all. From what I'm observing, mopher is a milter (so it might be compared with my another project called 'rmilter') and it can work with Spamassassin. Hence, if something can work with spamassassin then it will be capable to talk with rspamd at some extent.

Multiple database drivers are in plans for rspamd 1.0 (along with personal statistics and advanced rules planner). The tricky stuff here is that rspamd uses non-blocking model currently which is hardly supported by database drivers (excluding redis and some others). However, rspamd has a concept of asynchronous threads executed in thread pool. So something like MySQL query could be executed within this thread pool with no delay for other filters processing.