What is 'Resolver Lookahead' and how does it optimize database queries?

Lookahead involves analyzing the info object (AST) in a parent resolver to see what child fields are being requested.

Usually, a parent resolver fetches all data, and child resolvers pick out fields. With Lookahead, the parent checks if a heavy relational field (e.g., comments) is requested. If so, it performs an SQL JOIN immediately, entirely avoiding the N+1 problem without needing DataLoader.