SULID: Snowflake-inspired Universally Unique Lexicographically Sortable Identifier

SULID is a unique ID generation algorithm that combines the benefits of ULID and Snowflake. It offers a highly efficient, reliable, and lexicographically sortable identifier, which ensures uniqueness across multiple data centers and machines, making it ideal for high-concurrency distributed environments.

Features

• High Concurrency Support: Efficiently generates unique IDs in high-concurrency environments.
• Time Ordered: Retains the time-ordered characteristic of ULID.
• Distributed Uniqueness: Ensures unique IDs across distributed environments by incorporating data center and machine IDs.
• Readability: Produces shorter, human-readable identifiers.

Overview

SULID is based on the ULID (Universally Unique Lexicographically Sortable Identifier) format but incorporates additional bits for a data center ID and machine ID, similar to Snowflake. This design ensures uniqueness in distributed environments and maintains time-ordering characteristics, making it suitable for applications requiring both high concurrency and global uniqueness, such as microservice architectures, log tracking, and order generation.

ID Format

SULIDs have a unique structure comprising the following parts, adding up to a 128-bit identifier:

Version1

1. Timestamp: 48 bits, representing the epoch time in milliseconds.
2. Random Number: 70 bits of randomness to ensure uniqueness within the same millisecond.
3. Data Center ID: 5 bits, identifying the data center.
4. Machine ID: 5 bits, identifying the machine within the data center.

Here is a visual breakdown of the SULID format:

| 48-bit Timestamp | 70-bit Random Number | 5-bit Data Center ID | 5-bit Machine ID |

Version2

1. Timestamp: 48 bits, representing the epoch time in milliseconds.
2. Random Number: 70 bits of randomness to ensure uniqueness within the same millisecond.
3. Worker ID: 10 bits, the combination of data_center_id and machine_id.

Here is a visual breakdown of the SULID format:

| 48-bit Timestamp | 70-bit Random Number | 10-bit Worker ID |

Installation

To use SULID, add the following dependencies to your Cargo.toml file:

[dependencies]
sulid = "0.6"

Usage

Here's how you can use the SulidGenerator in your project:

use sulid::SulidGenerator;

fn main() {
    let generator = SulidGenerator::v1_new(1, 1);

    for _ in 0..3 {
        let id = generator.generate();
        println!("SULID-V1: {}", id);
    }

    let generator = SulidGenerator::v2_new(1);

    for _ in 0..3 {
        let id = generator.generate();
        println!("SULID-V2: {}", id);
    }
}

Example Output

Running the example code generates SULIDs such as:

SULID-V1: 01J75Y6K09Q0VD4D7HCF496K11
SULID-V1: 01J75Y6K09ZGD0ATFGNJ7TWZ11
SULID-V1: 01J75Y6K09DWG2RPNEXNYSRP11
SULID-V2: 01J75Y6K09FVT8QTQVYGSDJ401
SULID-V2: 01J75Y6K0A16WE3XQN92QPP701
SULID-V2: 01J75Y6K0AN12FBKX56YGZF301

Benefits

• High Concurrency Support: The algorithm is designed to generate IDs efficiently in environments with high concurrency, making it suitable for distributed systems.
• Time Ordered: SULID retains the time-ordering characteristic of ULID. This feature is beneficial for logging systems and event sourcing where chronological order is essential.
• Distributed Uniqueness: By incorporating data center and machine IDs similar to Snowflake's approach, SULID ensures IDs are unique across different machines and data centers.
• Readability: Compared to traditional UUIDs, SULID produces shorter and more human-readable identifiers, making them easier to work with in certain scenarios.
• Traceability: The time-ordered nature of SULID makes it easier to trace and debug events in distributed systems.

How It Works

SULID leverages both ULID and Snowflake's strengths:

• ULID: Provides lexicographically sortable identifiers based on a timestamp and randomness.
• Snowflake: Adds data center and machine IDs to ensure distributed uniqueness.

By combining these two approaches, SULID generates IDs that are globally unique, time-ordered, and suitable for high-concurrency distributed environments.

License

This project is licensed under the MIT License.