Does allow you to tune database usage?
Well, sort of.
What I mentioned is more like a protection state the site can enter into if the server load becomes too great. Your choices are this...
-If the system’s 1-minute load average exceeds a certain value, the board will automatically go offline.
-If the number of sessions exceeds a certain value within a one minute period the board will go offline.
(These can help keep bandwidth over-usage fees under control.)
On the other hand, you can control database load by controlling what general things are displayed on your board. That is, things that must rely on the database such as...
-Store read/unread status in cookies or in database.
-Display read/unread status for guests.
-Display online user information on index, forum and topic pages.
-Disabled the birthday listing.
-Enable display of moderators.
-Enable display of jumpbox.
-Show user’s activity.
-Displays active topic/forum in user profiles and user control panel. (It is recommended to disable this on boards with more than one million posts.)
-Recompile stale style components.
-Check for updated style components on filesystem and recompile.
-Display custom profile fields in user profiles.
-Display custom profile fields on topic pages.
You guys may be able to control a lot of those things already with any forum. It all contributes to database load/activity.