[ekipan]

I forget the context but the other day I also learned about Snowflake IDs [1] that are apparently used by Twitter, Discord, Instagram, and Mastodon.

Timestamp + random seems like it could be a good tradeoff to reduce the ID sizes and still get reasonable characteristics, I'm surprised the article didn't explore there (but then again "timestamps" are a lot more nebulous at universal scale I suppose). Just spitballing here but I wonder if it would be worthwhile to reclaim ten bits of the Snowflake timestamp and use the low 32 bits for a random number. Four billion IDs for each second.

There's a Tom Scott video [2] that describes Youtube video IDs as 11-digit base-64 random numbers, but I don't see any official documentation about that. At the end he says how many IDs are available but I don't think he considers collisions via the birthday paradox.

[1]: https://en.wikipedia.org/wiki/Snowflake_ID

[2]: https://youtu.be/gocwRvLhDf8

[buzzerbetrayed]

Getting the entire universe to agree on a single clock for creating timestamps sounds absurdly difficult. Probably impossible?

[ekipan]

"Agreement" of time is probably nonsense, yeah. I realized after posting so I edited in the parenthetical, but as [3] notes, locality probably makes this less of a real issue.

Apparently with the birthday paradox 32 bit random IDs only allow some tens of thousands per second before collision chance passes 50%. Maybe that's acceptable?

[3]: https://news.ycombinator.com/item?id=47065241

[Zambyte]

You don't need the universe to agree. You need your ID system to agree within a reasonable margin of error.

[speakeron]

The temperature of the cosmic microwave background can be used as a universal clock.

[UltraSane]

So can neutron star spin rates

[UltraSane]

Neutron star spins collectively can be used as a pretty accurate clock.

[CableNinja]

How? You are here on earth, looking at a neutron star. It pulses about N times a minute. I am 5ly away, looking at the same neutron star. Yes, i see the pulses happening at about N times per second, but the pulse delay you see at time T(a) is not the same pulse delay i see at time T(a), it would be another 5 years before i see the same pulse you saw.

[swiftcoder]

> [1]: https://en.wikipedia.org/wiki/Snowflake_ID

Isn't this just the same scheme as version 1 UUID, except with half the bits? I guess they didn't want to dedicate 128 bits to their IDs.

[bricss]

There also DRUUID: https://gist.github.com/bricss/53e5babedf44bf3ab71334c15102e...

[drchickensalad]

That also looks like the widely used BSON ids, to anyone else interested