The Almanac of UUIDs
A comprehensive journey through the philosophy, physics, and engineering of distributed identifiers. Understanding why we moved from Apollo NCS to RFC 9562.
Philosophy & Physics
The fundamental problem of distributed identity, collision probability, and the scale of the 128-bit space.
Historical Tapestry
From Apollo NCS and OSF DCE to Microsoft COM (GUIDs) and the IETF RFC 4122 standardization.
Structural Anatomy
Canonical representation, variant fields, endianness issues, and the structure of special UUIDs.
Legacy Standards
Deep dive into Version 1 (Time-based + MAC) and Version 2 (DCE Security), and why they are obsolete.
Namespace & Random
Understanding MD5/SHA-1 name-based IDs (v3/v5) and the industry standard Random UUID (v4).
The Database Crisis
How random writes destroy B-Tree index performance in relational databases like PostgreSQL and MySQL.
Modern Standards
The solution: RFC 9562. Detailed analysis of Version 6 (Reordered) and Version 7 (Unix Epoch).
Implementation Strategy
Practical guide to using PostgreSQL 18+ functions, live migration from v4 to v7, and regex validation.