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uuid

README.md

UUID

Universally Unique Identifier

Several uuid libraries are commonly used for integration.

Compare

Name Binary Size String Size Features Notes
go.uuid 16 bytes 36 chars configuration free, not sortable recommended V4
ksuid 20 bytes 27 chars configuration free, sortable collision-free, coordination-free, dependency-free
xid 12 bytes 20 chars configuration free, sortable not cryptographically secure

Notes

  • xid: dependent on the system time, a monotonic counter and so is not cryptographically secure.

Features

go.uuid

  • Version 1, based on timestamp and MAC address (RFC 4122)
  • Version 2, based on timestamp, MAC address and POSIX UID/GID (DCE 1.1)
  • Version 3, based on MD5 hashing (RFC 4122)
  • Version 4, based on random numbers (RFC 4122)
  • Version 5, based on SHA-1 hashing (RFC 4122)

ksuid

  1. Naturally ordered by generation time
  2. Collision-free, coordination-free, dependency-free
  3. Highly portable representations
  4. 20-bytes: a 32-bit unsigned integer UTC timestamp and a 128-bit randomly generated payload.
    1. The timestamp uses big-endian encoding, to support lexicographic sorting.
    2. The timestamp epoch is adjusted to May 13th, 2014, providing over 100 years of life.
    3. The payload is generated by a cryptographically-strong pseudorandom number generator.

xid

  • Size: 12 bytes (96 bits), smaller than UUID, larger than snowflake
  • Base32 hex encoded by default (20 chars when transported as printable string, still sortable)
  • Non configured, you don't need set a unique machine and/or data center id
  • K-ordered
  • Embedded time with 1 second precision
  • Unicity guaranteed for 16,777,216 (24 bits) unique ids per second and per host/process
  • Lock-free (i.e.: unlike UUIDv1 and v2)

Benchmarks

goos: darwin
goarch: amd64
pkg: github.com/v8fg/kit4go/uuid
cpu: Intel(R) Core(TM) i5-8279U CPU @ 2.40GHz
BenchmarkRequestID
BenchmarkRequestID-8                     1525274               778.1 ns/op            48 B/op          2 allocs/op
BenchmarkRequestIDCanonicalFormat
BenchmarkRequestIDCanonicalFormat-8      1529751               788.2 ns/op            64 B/op          2 allocs/op
BenchmarkNewV4
BenchmarkNewV4-8                         1677464               740.2 ns/op            16 B/op          1 allocs/op
BenchmarkNewKSUID
BenchmarkNewKSUID-8                      1453513               794.9 ns/op             0 B/op          0 allocs/op
BenchmarkNewKSUIDRandomWithTime
BenchmarkNewKSUIDRandomWithTime-8        1534045               760.3 ns/op             0 B/op          0 allocs/op
BenchmarkNewXID
BenchmarkNewXID-8                       13338049                85.44 ns/op            0 B/op          0 allocs/op
BenchmarkNewXIDWithTime
BenchmarkNewXIDWithTime-8               14852886                80.44 ns/op            0 B/op          0 allocs/op