O'Reilly logo

SQL for eServer i5 and iSeries by Kevin Forsythe

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Chapter 5. Optimizing SQL

This chapter reviews the various methods for improving the performance of your SQL statements. Monitoring and measuring tools, such as Debug and the GUI Visual Explain are reviewed. The significance of the query attribute file (QAQQINI) is discussed. The role of indexes within an SQL database is also covered. All these topics relate to the relative performance of an SQL statement—that is, never to its ability to run, only the speed at which it runs.

Using Debug to Optimize SQL Statements

Debug is the easiest performance monitoring tool to use and the most familiar for developers of traditional applications on the iSeries. To start Debug, simply initiate a 5250 session and key in the command:

STRDBG

This activates the interactive ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required