On: UUIDs are popular, but bad for performance (2019)

[inetknght]

Is this sarcasm? If you generate an incrementing-UUID then its predictability is going to make it not-universally unique too

[michaelmcmillan → inetknght]

No. Incrementing an integer might be unique for the local database, but not unique for the universe.

[rco8786 → inetknght]

That is…not what universally unique means.

[rwoerz → rco8786]

From RFC4122: "A UUID is an identifier that is unique across both space and time, with respect to the space of all UUIDs."

Hard to achieve if everyone starts from 00000000-0000-0000-0000-000000000000.

[rco8786 → rwoerz]

Right that’s why nobody starts at 0. And you don’t have to only add 1 to be ordered, no DB I’m aware of just adds 1 to sequential UUIDs. There’s always randomness/entropy involved.

[ztorkelson → rwoerz]

Sequential UUIDs don’t start at 0. They are a 128-bit composite of two integers; a temporal component in the high order bits and a random component in the low order bits.