You're right, but the point here is that positional queries are boolean queries plus positions. For example, document that match 'a NEAR b' are a subset of docu

You're right, but the point here is that positional queries are boolean queries plus positions. For example, document that match 'a NEAR b' are a subset of documents matching 'a AND b'. So if 'a AND b' has no matches, there is no need to execute the more expensive 'a NEAR b'.