KSUID

KSUID, or K-Sortable Unique Identifier, is a type of identifier designed to provide unique, chronologically sortable IDs. Developed by Segment, KSUIDs are particularly useful in distributed systems and applications where the order of events is crucial, offering a blend of global uniqueness and temporal ordering.

Structure of KSUID

A KSUID is composed of two parts: a 32-bit timestamp and a 128-bit random component. This structure ensures that KSUIDs generated at different times are inherently ordered based on their creation time, making them ideal for scenarios where chronological sorting is important.

Format of KSUID

tttttttt-rrrr-rrrr-rrrr-rrrr-rrrr-rrrr

• t represents the timestamp, encoded as 4 bytes.
• r represents the random component, encoded as 16 bytes.

Benefits of using KSUIDs

• Uniqueness: KSUIDs are designed to be globally unique, reducing the risk of identifier collisions in distributed systems. The large 128-bit random component ensures a vast space for unique IDs.
• Chronological Sorting: The timestamp component of KSUIDs ensures that they can be sorted chronologically without additional processing, making them ideal for applications where the order of events is critical.
• Compactness: While not as compact as some other identifiers, KSUIDs are still more readable and manageable due to their base62 encoding, which makes them suitable for use in URLs and other contexts where readability is important.
• Efficiency: KSUIDs can be generated quickly and independently on multiple nodes without requiring synchronization, making them efficient for high-throughput applications.

Downsides of using KSUIDs

• Less Widely Adopted: Like ULIDs, KSUIDs are not as widely adopted as UUIDs, which may limit their compatibility with certain systems and libraries.
• Complexity: The inclusion of a timestamp and a large random component in KSUIDs adds complexity compared to simpler sequential identifiers, potentially increasing the implementation overhead.

KSUID vs. UUID

• Uniqueness: Both KSUIDs and UUIDs are designed to be globally unique, but KSUIDs achieve this by combining a timestamp with a large random component, while UUIDs rely solely on randomness.
• Sortability: KSUIDs are lexicographically sortable based on their timestamp, which UUIDs are not.
• Readability: KSUIDs, encoded in base62, are more readable and URL-friendly compared to the hexadecimal encoding of UUIDs.

In summary, KSUIDs offer a powerful combination of global uniqueness and chronological sorting, making them well-suited for use in distributed systems and applications where the order of events is important. Their readability and efficiency further enhance their suitability for a variety of use cases.