some of this information might be useful -

http://code.google.com/p/google-mysql-tools/wiki/MysqlRateLi...

http://www.seoservicesgroup.com/blog/2010/07/do-you-ever-hea...

Also during various ancestry promotions, the site is hit by a larger number of newbies, which in turn slow down the paid members. I wonder if their might be a way to restrict non-subsribers to a (s)lower level/priority of access.