pULID

• ULID compatible
• UUIDv4 compatible
• Time based
• with entropy abstraction optimized
• scope bytes can be used to store relevant information - such as entities types or namespaces
• scope 65535 and 0 are protected and used within th lib

What different on ours?

• Use of 7th and 8th byte to store scope type
• 2^{16} = 65536 - 2 = 65534 scope types available
• entropy used allows for concurrent calls
• uuid v4 compatible

pULID Structure

  6bytes   2bytes    8bytes
| ------ | | -- | | -------- |
   epoch.  scope   entropy

Structure:

flowchart LR
    subgraph pULID
        A[Timestamp<br/>6 bytes] 
        B[scope Type<br/>2 bytes] 
        C[Entropy<br/>8 bytes]
    end

Loading

pULID strings example:

for MaxScopeValue - 65535:

UUID: 0194AA0E-DCDE-FFFF-53F2-18257F60B037
ULID: 01JJN0XQ6YZZZN7WGR4NZP1C1Q
TS: 2025-01-27T23:18:08.350Z

UUID: 0194AA16-4A77-FFFF-4937-5547C5791AB7
ULID: 01JJN1CJKQZZZMJDTN8Z2QJ6NQ
TS: 2025-01-27T23:26:15.159Z

for Scope value 567

UUID: 0194AA15-34AB-0237-22E7-0B92B8C5F1B7
ULID: 01JJN1AD5B08VJ5SRBJAWCBWDQ
TS: 2025-01-27T23:25:04.043Z

UUID: 0194AA16-4A77-0237-42A9-56B6A8CBF3FF
ULID: 01JJN1CJKQ08VM5AAPPTMCQWZZ
TS: 2025-01-27T23:26:15.159Z

Supported Database Drivers

• pgx (coming soon)
• gorm (coming soon)
• sql.DB (coming soon)

Benchmark

goos: darwin
goarch: arm64
pkg: github.com/pixie-sh/ulid-go
cpu: Apple M3 Max
BenchmarkNanoIDGeneration-16         	 4081274	       288.0 ns/op
BenchmarkAnotherULIDGeneration
BenchmarkAnotherULIDGeneration-16    	 9510402	       125.9 ns/op
BenchmarkpULIDGeneration
BenchmarkpULIDGeneration-16           	 8371111	       139.2 ns/op
BenchmarkUUIDGeneration 
BenchmarkUUIDGeneration-16           	 4945442	       246.9 ns/op
PASS

Thank you

• github.com/google/uuid
• github.com/matoous/go-nanoid/v2
• github.com/oklog/ulid
• github.com/RobThree/NUlid
• github.com/segmentio/ksuid