title: Postgres UUID with indexes and constraints
body: <p>What are the benefits of having an index and a unique constraint on a primary key field that is a UUID?  It seems that if I have 25M records and I have to insert a new record, all 25M records have to be searched and checked that they don't have the same UUID with or without an index.  Finding that record is also troublesome as uuid's can't be sorted.  Am I missing something?</p>