The relationship between bulk loading and unnest is as follows. A single insert of an array using an unnest can insert many rows. The performance is worse tha

The relationship between bulk loading and unnest is as follows. A single insert of an array using an unnest can insert many rows. The performance is worse than copy to, but in the same ballpark. But there are use cases where you'd like to bulk load through a stored procedure for a variety of reasons, and now calling the procedure with an array and using unnest internally is a straight win.