Building BM25 Keyword Search In Postgres

It turns out, you can build a surprisingly powerful keyword search, known as BM25, with just a handful of SQL functions. What follows is my journey including what I've learned, how this algorithm works in simple terms, and how I implemented it without any external dependencies. The Foundation: From TF-IDF to BM25 Before diving into BM25, it's helpful to understand TF-IDF (Term Frequency-Inverse…