alt Hacker News> You're not going to try and extract a timestamp from a uuid.
What? The first 48 bits of an UUID7 are a UNIX timestamp.
Whether or not this is a meaningful problem or a benefit to any particular use of UUIDs requires thinking about it; in some cases it’s not to be taken lightly and in others it doesn’t matter at all.
I see what you’re getting at, that ignoring the timestamp aspect makes them “just better UUIDs,” but this ignores security implications and the temptation to partition by high bits (timestamp).
Nobody forces you to use a real Unix timestamp. BTW the original Unix timestamp is 32 bits (expiring in 2038), and now everyone is switching to 64-bit time_t. What 48 bits?
All you need is a guaranteed non-decreasing 48-bit number. A clock is one way to generate it, but I don't see why a UUIDv7 would become invalid if your clock is biased, runs too fast, too slow, or whatever. I would not count on the first 48 bits being a "real" timestamp.