Postgres UUIDv7 and per-back end monotonicity

My org has been using ULID[0] extensively for a few years, and generally we've been quite happy with it. After initially dabbing with a few implementations, I reimplemented the spec in Kotlin, and this has been working out quite well for us. We will open-source our implementation in the following weeks.

ULID does specifically require generated IDs to be monotonically increasing as opposed to what the RFC for UUIDv7 states, which is a big deal IMHO.

[0]: https://github.com/ulid/spec

Having used a lot of the ULID variants that the UUIDv7 spec cites as prior art, including the ULID spec you link to, I've gotta say that UUIDv7 has some real advantages.

The biggest advantage is that it is hex. Haven't yet met a database system that doesn't have functions for substr and from_hex etc, meaning you can extract the time part using vanilla sql.

ULID and others that use custom variants of base32 or base62 or whatever are just about impossible to wrangle with normal tooling.

Your future selfs will thank you for being able to manipulate it in whatever database you use in the future to analyse old logs or import whatever data you generate today.