On my site, we don't use the internal messaging system (no messages block, not using pop-ups, users don't have permission to message each other), but we do want the system to send emails to users when they have received grades and if they are subscribed to a forum.
It appears that this still adds items to mdl_read_messages in the database, causing a size issue with my web host. I recently backed up these entries (just in case) and emptied them.
Is there a way to allow for emails to be sent for the above conditions but NOT write data to mdl_read_messages?