https://tech.daniellbastos.com.br/tags/query-planner/Recent content in Query Planner on Daniel's Tech BlogHugoen-usSat, 18 Apr 2026 00:00:00 +0000https://tech.daniellbastos.com.br/posts/chapter-5-joins-and-planner/Sat, 18 Apr 2026 00:00:00 +0000https://tech.daniellbastos.com.br/posts/chapter-5-joins-and-planner/<blockquote> <p>This post continues the study of <a href="https://courses.cs.duke.edu/compsci516/cps216/spring03/papers/selinger-etal-1979.pdf">Access Path Selection in a Relational Database Management System (Selinger et al., 1979)</a>, now covering chapter 5. I used available internet resources and tools to go deeper on the examples and make the concepts more concrete.</p> </blockquote> <h2 id="what-chapter-5-covers">What chapter 5 covers</h2> <p>Chapter 5 covers joins. The paper describes two methods, nested loops and merging scans, and how the optimizer picks between them. It also describes join order selection: given N tables, which one to read first, which second, which last.</p>