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ULID: Universally Unique Lexicographically Sortable Identifier

(packagemain.tech)
68 points der_gopher | 1 comments | 01 Dec 25 20:45 UTC | HN request time: 0.216s | source
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sedatk ◴[09 Dec 25 22:26 UTC] No.46211578[source]▶
Whenever ULID comes up, I need to remind that it has a sequential ID generation mode in its spec which is prone to conflicts on multi-threads, processes or hosts which kills the purpose of a "universal" identifier. If you need a sequential ID, just use an integer, preferably one that's autoincremented by the database.

It's best to stick to UUIDv7 because of such quirks of ULID.

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1. skeledrew ◴[10 Dec 25 03:19 UTC] No.46213609[source]▶
Actually dived into this a bit just a couple days ago. It's very near impossibly for there to be a conflict since the timestamp resolves at the microsecond level, and if it's among threads, then there's a global state that, if somehow it should be hit 2+ times in the same microsecond, ensures detection and the random portion is incremented.