I'm working on updating the database structure of the messaging system. You may notice a temporary outage of message viewing while this goes on. Hopefully, everything will be much faster in the end, once 2.8M messages on 800MB hard disk space (MySQL database table) are processed.
UPDATE
I believe everything is ready, now. The body component of messages has been split into a separate database table that is only accessed when reading or composing messages. Let me know if you see any errors moving forward.