Book Image

OCA Oracle Database 11g: Database Administration I: A Real-World Certification Guide

Book Image

OCA Oracle Database 11g: Database Administration I: A Real-World Certification Guide

Overview of this book

Oracle Database Server is the most widely used relational database in the world today. This book gives you the essential skills to master the fundamentals of Oracle database administration and prepares you for Oracle DBA certification."OCA Oracle Database 11g: Database Administration I: A Real-World Certification Guide" prepares you to master the fundamentals of Oracle database administration using an example driven method that is easy to understand. The real world examples will prepare you to face the daily challenges of being a database administrator.Starting with the essentials of why databases are important in today's information technology world and how they work, you are then guided through a full, customized installation of the Oracle software and creating your own personal database. We then examine fundamental concepts of Oracle, including architecture, storage structures, security, performance tuning, networking, and instance management. Finally, we take an in-depth look at some of the most important concepts in the daily life of an Oracle DBA - backup, recovery, and data migration."OCA Oracle Database 11g: Database Administration I: A Real-World Certification Guide" provides you with the skills you need in order to become a successful Oracle DBA, both for certification and real life tasks.
Table of Contents (24 chapters)
OCA Oracle Database 11g: Database Administration I: A Real-World Certification Guide
Credits
Foreword
About the Author
About the Reviewer
www.packtpub.com
Preface
Index

Understanding object-level tuning


Performance tuning boils down to the user experience. Bad performance derives from the very subjective notion that a given application is somehow different from the acceptable norms. The common complaint heard from the user is, "It was fast yesterday but it's slow today". It is the job of the DBA to take these subjective ideas and discover objective facts that point to the cause for this unacceptable performance. In the end, database performance tuning is an analysis of why SQL statements are executing at a suboptimal rate. Even if the root cause is CPU starvation, incorrect configuration parameters, or just a poorly written DELETE statement, the key is first finding out what is slow and then what can be done to rectify the situation. Thus, it is wise to look first at how SQL statements are executed against database objects and what conditions can affect how they are executed.

Understanding the Oracle optimizer

Let's take the following simple SQL statement...