Preparing for and Tuning the SQL Query Engine on DB2 for i5/OS

®

SG24-6598-01 ISBN 0738494992

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Preparing for and

Tuning the SQL Query

Engine on DB2 for i5/OS

Understand the new

architecture for query

processing

Learn about the data

access methods and

Statistics Manager

See how to monitor

and tune the SQL

engine

The IBM System i family, which encompasses the IBM AS/400, eServer

iSeries, eServer i5, and System i5, has a successful 24-year history of

satisfying hundreds of customers’ requirements, thanks to its developers.

DB2 for i5/OS, also known as DB2 Universal Database for iSeries, is deeply

rooted in the architecture and heritage of the AS/400 and its predecessor

System/38.

The database has undergone significant changes over the years to

maintain its competitive advantage including fundamental changes to the

structure of the database to compete successfully in the industry. In doing

so, IBM Rochester launched a project to re-engineer and redesign

important components of the database. The redesigned components were

architected using object-oriented design concepts and then implemented

using object-oriented implementation techniques.

The query optimizer was one of the key components that was redesigned.

This IBM Redbook gives a broad understanding of the architectural

changes of the database concerning the query optimizer. It explains the

following concepts:

򐂰 The architecture of the query optimizer

򐂰 The data access methods used by the query optimizer

򐂰 The Statistics Manager included in V5R2

򐂰 The feedback message changes of the query optimizer

򐂰 Some performance measurements

򐂰 Changes and enhancements made in V5R4

The objective of this redbook is to help you minimize any SQL or database

performance issues when upgrading to OS/400 V5R2 or V5R3 or to IBM

i5/OS V5R4. Prior to reading this book, you should have some knowledge

of database performance and query optimization.

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