RFC9562 was released almost two weeks ago, so we can replace the "draft"
UUIDv7 URL with the final RFC URL too. RFC9562 obsoletes RFC4122, so I
replaced its link as well.
https://github.com/ruby/securerandom/commit/1e41c3d2cb
Although the specification for UUIDv7 is still in draft, the UUIDv7
algorithm has been relatively stable as it progresses to completion.
Version 7 UUIDs can be very useful, because they are lexographically
sortable, which can improve e.g: database index locality. See section
6.10 of the draft specification for further explanation:
https://datatracker.ietf.org/doc/draft-ietf-uuidrev-rfc4122bis/
The specification allows up to 12 bits of extra timestamp precision, to
make UUID generation closer to monotonically increasing. This provides
between 1ms and ~240ns of timestamp precision. At the cost of some code
complexity and a small performance penalty, a kwarg may specify any
arbitrary precision between 0 and 12 extra bits. Any stronger
guarantees of monotonicity have considerably larger tradeoffs, so
nothing more is implemented. This limitation is documented.
Ruby issue: https://bugs.ruby-lang.org/issues/19735https://github.com/ruby/securerandom/commit/34ed1a2ec3