Developers · Updated 23 Oct, 10:09 pm IST
UUIDv7’s timestamp and monotonicity guarantees are not reliable
Why it matters for readers: It shows that standards and implementations can differ, so read RFCs and docs before trusting ID formats for time or ordering.
- Many posts claim UUIDv7 gives monotonically increasing IDs, useful embedded timestamps, and unguessability, but those properties are not strictly held.1
- RFC 9562 permits implementations to alter the timestamp field, so the embedded timestamp may not reflect the object creation time.1
- Postgres documentation warns that uuid_extract_timestamp may not equal the time the UUID was generated, undermining reliance on the UUID timestamp.1
- The post concludes that uniqueness (collision resistance) is the only reliably provided property of UUIDv7.1
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