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A comment on Ask HN: We just had an actual UUID v4 collision.... Parent comment

Re:Ask HN: We just had an actual UUID v4 collision... by kdps on Friday May 08, 2026 @04:23PM (#48068310)
I get why sync of mutiple machines matters for ordering and causality, but why is it a problem for uniqueness?
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Re:Ask HN: We just had an actual UUID v4 collision... by dgellow on Saturday May 09, 2026 @07:28AM (#48074060)
I just read UUIDv7, something I wasn't familiar with until now. That does address everything I had in mind yes. I assumed timestamp-uuid meant purely based on the timestamp precision, in which case you can get conflicts if you don't have a reliable clock across your system.

But UUIDv7 looks pretty awesome:

> What is a Version 7 UUID made from?

> unix_ts_ms: 019e0c7bfe93

> ver: 7

> rand_a: 0b6

> var: b

> rand_b: 55a99e023294673

So please ignore my previous comment :)

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