Avoid UUID Version 4 Primary Keys (for Postgres)
Introduction Over the last decade, when working on databases with UUID Version 41 as the primary key data type, these databases have usually had bad p...
Database Internals
Summary
A PlanetScale blog post explaining how B-trees work as the foundation for database indexes, covering their structure, ordering properties, and why primary key choice (like UUIDs) impacts index performance.
Highlights
- B-trees store key/value pairs in ordered tree structures used by MySQL, Postgres, MongoDB, and other DBMSs for efficient lookups
- Formal B-tree properties include minimum fill factors, uniform leaf depth, and ordered keys within each node
- Using UUIDs as primary keys can degrade index performance due to random insertion patterns
- The article includes interactive animations to visualize B-tree insertion and node splitting
auto-generated
Context
Audience
Software developers and database engineers who want to understand how database indexes work under the hood and make informed primary key decisions
DomainDatabase Systems
Formatlong-form technical article with interactive visualizations
Accessfree online
Source Overview
B-trees are used by many modern DBMSs. Learn how they work, how databases use them, and how your choice of primary key can affect index performance.
Topics
Related
B+tree vs B-treeInnoDB index structureUUID vs auto-increment primary keysLSM-treesDatabase index design patterns
