Exactly. Async is very important when you're blocking on an external event (such as fetching a page doing doing hanging-GET), but local db or filesystem blockin

Exactly. Async is very important when you're blocking on an external event (such as fetching a page doing doing hanging-GET), but local db or filesystem blocking can most easily be handled by just running more Tornado instances (because they better not be blocking for too long anyway, or else your site is dead).