Queries are the centerpiece of MySQL and they have high optimization potential (in conjunction with indexes). This is specially true for big databases (whatever big means).
One Drupalcon session of particular interest to many in the community, since the first of them, has been the “Q&A with Dries”, a core-conversation -track, where
There is the European DrupalCon happening from Sept. 29th to the Oct. 3rd in Amsterdam and a team of Cocomore - as one of the biggest Drupal shops in Germany and Spain - will of course attend.