We all write SQL, but how many of us have looked under the hood of a relational database like PostgreSQL? This talk is a deep dive into the guts of the database engine, tracking a simple SELECT statement from the moment you hit "Enter" to the final result set.

We'll lift the veil on the core components: the parser, the planner (and the optimizer's black magic!), and the executor, and see how they transform a text string into a low-level, high-performance operation. Using a live, interactive session on a PostgreSQL instance, we'll expose the role of the shared buffer cache, explain why an index works (or doesn't), explore the true cost of I/O, and understand the significance of the binary log (WAL) on read operations.

Whether you're a developer frustrated with slow queries or a database administrator looking to squeeze out every millisecond of performance, you'll leave this talk with a mental model that demystifies query execution and gives you the knowledge to write queries that fly.