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

Tuning sorting


Sorting occurs at two levels in the database. One is shared sort memory, located in the database global memory, and the other is at the agent level, called the private sort memory.

Getting ready

Monitor sorting activity on your database, as discussed in the previous chapter, by using snapshots, and compare sorting activity with the load on your database.

See how much sorting is done throughout a normal day's activity. In the following SQL, you can even identify the partition's sorting activity. You will see if there is enough sorting activity to make tuning worthwhile.

How to do it...

  1. Average sort time: If average sort time per sort is long, we can start thinking about tuning.

    SELECT DBPARTITIONNUM, TOTAL_SORT_TIME / (TOTAL_SORTS + 1)
    FROM   SYSIBMADM.SNAPDB;
    
  2. Sort time per transaction: If the value of SortsPerTransaction is greater than five, there might be too many sorts per transaction:

    SELECT DBPARTITIONNUM, TOTAL_SORTS / ( COMMIT_SQL_STMTS + ROLLBACK_SQL_STMTS + 1)
    FROM ...