PERFORMANCE: Move from pgcrypto to built-in gen_random_uuid():
  Curtis Summers (https://github.com/csummers)

PERFORMANCE: Use set_bit to upgrade v4 to v7, not set_byte:
PERFORMANCE: Reduce local variable use while still being maintainable
  Rolf Timmermans (https://github.com/rolftimmermans)