ULID and TSID

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Programming/ Java
| Java

ULID and TSID

ULID

UUID can be suboptimal for many uses-cases because:

  • It isn’t the most character efficient way of encoding 128 bits of randomness
  • UUID v1/v2 is impractical in many environments, as it requires access to a unique, stable MAC address
  • UUID v3/v5 requires a unique seed and produces randomly distributed IDs, which can cause fragmentation in many data structures
  • UUID v4 provides no other information than randomness which can cause fragmentation in many data structures

Instead, herein is proposed ULID:

  • 128-bit compatibility with UUID
  • 1.21e+24 unique ULIDs per millisecond (48 bit ms + 80 bit randomness)
  • Lexicographically sortable!
  • Canonically encoded as a 26 character string, as opposed to the 36 character UUID
  • Uses Crockford’s base32 for better efficiency and readability (5 bits per character)
  • Case insensitive
  • No special characters (URL safe)
  • Monotonic sort order (correctly detects and handles the same millisecond in the same generator instance)

TSID

TSID is a general-purpose trend sorted identifier generator, it is the variant version of ULID, since ULID is often overkill. TSID don’t strict guaranty sort order in the same millisecond or microsecond.

  • 48 bit ms + 32 bit randomness = VARCHAR(16), 8919 year
  • 58 bit us + 42 bit randomness = VARCHAR(20), 9133 year
  • 58 bit us + 62 bit randomness = VARCHAR(24), 9133 year
  • 48 bit ms + 80 bit randomness = VARCHAR(26), 8919 year