We take a look at the PostgreSQL code, focusing on the query planning and optimization logic. Query planning is the heart of a database system, since it's what lets you write queries in declarative syntax with the confidence that they'll execute efficiently. The Postgres optimizer code is complicated and full of postgres-specific acronyms. In some cases, we have to drill down three or four functions in the call hierarchy before we see how an algorithm actually works. Nevertheless, we're able to paint a good picture of what the optimizer is doing and how it does it. Useful links: - Site: https://www.postgresql.org/ - Code: https://git.postgresql.org/gitweb/?p=postgresql.git - GitHub Mirror: https://github.com/postgres/postgres.git - A good overview of the optimizer: https://www.youtube.com/watch?v=wLpcVM9qxV0 - Relational algebra: https://en.wikipedia.org/wiki/Relational_algebra My related videos: - SQLite: https://www.youtube.com/watch?v=emCX4_PQXfI Join the Ants Are Everywhere Discord channel at https://discord.gg/YNtU8Yw7yT