Anatomy of a Join
A lot of database professionals today do not have a Computer-Science Degree so they never attended a “Introduction to Databases” course. In this session we are trying to fix at least one thing and we’ll look in depth at the three types of join operations, visualize how their algorithms work in order to understand how query plans are computed, explain why these join operations have very different performance characteristics and why the optimizer chooses a specific join operator to use in a query plan. Will demonstrate that empirical cost calculations are similar to what Query Optimizer actually outputs. Good understanding of join algorithms is vital in order to diagnose and remedy issues related to bad query plans.