I've been testing out the new Kunena 2.0 on my demo site. I also keep com_multisites on it to test out multisites when I'm not sure about something. A couple days ago, I received a message from my host telling me that some of my queueies have been taking up too many system resources and need to be optimized. After looking at the problem, I saw that this is because of some interaction between com_multisites and Kunena 2.0. I figured I'd posted the message here in hopes that you may be able to rectify the problem.

Here's the message:

Perhaps that kunena require some additional index to optimize the queries.

Did you enabled statistics in your MySQL to get more info on the queries that would consume too much resource ?
If not, try enabling it to get more info on the queries that consume too much resource.