Agreed. While it's an uncommon scenario it is a significant case and UUID shouldn't be used in that case because as you write checking doesn't work well. Better to use an alternative such as coordinate/reserve monotonic producer IDs that get paired with monotonic, per-producer monotonic sequence IDs to produce guaranteed unique, well-ordered IDs.

[edit: in IOT it's common to issue x509 certificates as a type of authentication which could be used instead of using producer IDs. Solutions always have to be paired to use case.]

Yeah, that was a little sloppy but it's generating is more expensive than not generating. In more words, generating an id and validating uniqueness is more expensive than only validating uniqueness.

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I suspect you meant to reply to a different comment. Regardless the most plausible speculation I've read here is that the RNG used to generate the UUID is low quality.

as would be a million things that don’t involve using uuids at all. it literally means nothing to say “this can be handled by centralizing your uuid store”… if you do that, you DON’T NEED UUIDS. THAT IS THE POINT!