Book Image

IBM DB2 9.7 Advanced Administration Cookbook

Book Image

IBM DB2 9.7 Advanced Administration Cookbook

Overview of this book

IBM DB2 LUW is a leading relational database system developed by IBM. DB2 LUW database software offers industry leading performance, scale, and reliability on your choice of platform on various Linux distributions, leading Unix Systems like AIX, HP-UX and Solaris and MS Windows platforms. With lots of new features, DB2 9.7 delivers one the best relational database systems in the market. IBM DB2 9.7 Advanced Administration Cookbook covers all the latest features with instance creation, setup, and administration of multi-partitioned database. This practical cookbook provides step-by-step instructions to build and configure powerful databases, with scalability, safety and reliability features, using industry standard best practices. This book will walk you through all the important aspects of administration. You will learn to set up production capable environments with multi-partitioned databases and make the best use of hardware resources for maximum performance. With this guide you can master the different ways to implement strong databases with a High Availability architecture.
Table of Contents (21 chapters)
IBM DB2 9.7 Advanced Administration Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Using EXPLAIN PLAN


SQL tuning should be done as early as possible in the development process. Often SQLs will be developed on small development databases and will probably make it to the QA database, and even into production, with acceptable performance. When the database grows, it's not unusual to find out the same query keeps getting slower and slower. This is where you will have to check access plans.

Getting ready

Now, before you can perform any explain or performance analysis, we need fresh statistics or reasonably recent ones, on tables and indexes. Otherwise, the results may not correspond with your expectations.

How to do it...

  1. User with create table privileges: If you're not connecting as instance owner, you will need a user with create table authority to run the EXPLAIN.DDL utility, as the instance owner grants database access to the user who will perform SQL evaluations. That user should have profile values set and can execute DB2 from the shell or Windows command line.

    db2 connect...