On Sat, Jan 28, 2023 at 8:02 PM Ron <ronljohnsonjr@xxxxxxxxx> wrote: > > Then it's not a Type 4 UUID, which is perfectly fine; just not random. Yep, which is why it really should be re-versioned to UUIDv8 to be pedantic. In everyday use though, almost certainly doesn't matter. > Also, should now() be replaced by clock_timestamp(), so that it can be > called multiple times in the same transaction? Not necessary. Instead of 122 bits of entropy, you get 106 bits of entropy and a new incremented prefix every minute. now() vs clock_timestamp() wouldn't make a substantive difference. Should still be reasonably safe against the birthday paradox for more than a century when creating more than a million UUIDs per second.