[dragonwriter]

> Well that’s the center of the issue, right? OP’s interpretation was that PostgreSQL did not document such, and so it shouldn’t be relied upon.

And the correct answer is…we don’t know. We have a commit that landed and the explanation of the commit; we don’t have the documentation for the corresponding release of Postgres, because…it doesn’t exist yet. Because monoticity is an important feature for UUIDv7, it would be very odd if Postgres used an implementation that took the extra effort to use a nanosecond-level time value as the high-order portion of the variant part of the UUID instead of the minimum millisecond-level time, but not document that, but any assumption about what will be the documented, reliable-going-forward advertised feature is speculative until the documentation exists and is finalized.

OTOH, its perfectly fine to talk about what the implementation allows now, because that kind of thing is important to the decision about what should be documented and committed to going forward.