B-trees and database indexes

This post provides a deep dive into the mechanics of B-trees and B+trees, explaining their structure, properties, and how they are used for indexing in database systems like MySQL and PostgreSQL. It includes interactive visualizations to demonstrate node operations, key insertion, and searching. The post specifically details how InnoDB uses B+trees for primary and secondary indexes, and analyzes the performance implications of choosing sequential integer primary keys versus random UUIDs, particularly concerning insertion patterns and data distribution. It highlights how sequential keys lead to more predictable and efficient insertions by favoring the right-most path of the tree and keeping data sorted at the leaf level, thus minimizing disk I/O and improving overall query performance.