That never happens though. Drupal has to bootstrap itself so it loads it's registry cache, variables cache, current user record (split across at least four tables to pull in the user account, associated roles, and user access permissions), any dynamic menu builds are going to the menu table, access callbacks and other function calls associated with dynamic menu rendering may also trigger other database calls, uncached content blocks have to be pulled out of the database, and we haven't even gotten to loading the node for the page which could be split across a bunch of tables if the content type has fields added to it...