Tuning queries like an optimizer developer

This presentation is a deep dive into analyzing query performance situations. The best practices approach utilized by Db2 for z/OS query performance diagnosis team. This presentation walks through what information is used, how information is layered onto the query, explain information, and optimizer choices information - and how to use it to evaluate a chosen access path versus alternates. While this presentation is targeted to Db2 for z/OS, the principles apply to evaluating query performance for any relational database.