4 ms·

The tails.

• yummyfajitas 14y ago
  You also often need to scan the whole data set in order to sample properly. Suppose you are interested in user behavior. You want sample(group_by(user_ident, all_user_events)), not group_by(user_ident, sample(all_user_events)). This involves running a group_by on the full data set.
  • tel 14y ago
    Or counting the number of events for each user as they come in.