For many years now IBM have positioned SQL as the primary interface to the database on IBM i. At the same time, new capabilities are being added only to SQL, not to the native database interface.
We need a different tool to understand and analyze query implementation plans and feedback from the optimizer – the SQL component that determines the most effective way to deliver the data we ask for in SQL statements. Visual Explain is just such a tool, and it both shows us graphically what plan the optimizer has chosen, as well as tells us details about each step along the way. It can also give us suggestions on ways to improve performance of our queries.
Learning Objectives: A brief description of optimization with SQL The several ways of invoking Visual Explain The various panes of the Visual Explain window Some features of Visual Explain for managing how it behaves Examples of improved performance after using suggested changes
