Explain explained. What is explain telling me and how to optimize
Toine Michilese, Broadcom
SQL is a very powerful language. To support it the Db2 optimizer has many ways to get to the data and combine partial results into the final result set. even though many tools are available to visualize the access path Db2 plans to execute, the output can be complex to understand. Breaking it down to the the basic elements and understanding the way data is accessed by those elements will enable less experienced developers and DBA’s to find performance problems quickly.