B-trees and database indexes — PlanetScale

Link: B-trees and database indexes — PlanetScale: "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."

Linked is a neat article explaining a lot about b-trees. Especially notable are the excellent visualization and animations which gave me a new way to understand these incredibly important data structures.