A SQL Query's Roadtrip Through Postgres
Ever wonder what happens when you type SELECT * FROM users WHERE id = 42; and hit Enter? That simple query triggers a fascinating journey through PostgreSQL’s internals—a complex series of operations involving multiple processes, sophisticated memory management, and decades of optimization research.
This is the first article in a series where we’ll explore PostgreSQL’s query execution in depth. In this overview, I’ll walk you through the complete journey from SQL text to results, giving you the roadmap. Then, in subsequent articles, we’ll dive deep into each component—the parser, analyzer, rewriter, planner, and executor—exploring the details of how each one works.