UUID7 was first drafted a bit over a year ago: https://datatracker.ietf.org/doc/html/draft-peabody-dispatch...

That's kinda what I figured. So you can see my confusion.

Perhaps one of many on this list[1]? ULID is listed as having 1.21e+24 unique per millisecond. I have no idea though about what may match up with your timeline(s).

[1] https://github.com/swyxio/brain/blob/master/R%20-%20Dev%20No...

Were they not happy due to possible collisions or something else?

Yeah they had a problem where the amortized ID rate was less than the number of valid UUIDs you could generate in a given time interval, but with a peak rate well above that, so UUIDs weren't quite going to function for naming/numbering them. You gotta be pushing a lot of messages through a system to hit that, but it's possible. And adding more layers of coordination on top of something meant to reduce coordination overhead tends to... make things messy.

I've half-heartedly tried to look up his problem every time I've had to introduce UUIDs to something (most recently fixing agents not generating correlation IDs), and I have not figured out which version of UUID he was talking about. I now suspect it was some proprietary or industry-specific quote-unquote UUID spec rather than an industry wide one. I may look through the UUID7 spec at some point to see if they mention prior art. Much more plausible than him being a time traveler.

UUIDv7 was first proposed just a few years ago, but the rfc contains a good list of well known ULID systems that predate it.

Putting the timestamp in the high bits of random ids is a “trick” i learned from DBAs (that used to be a thing!) in the 90s. And often the drive was to improve DB insert performance as it was for the other uses of an ID you can order and reason about.)