Book Image

Oracle Database 11g : Underground Advice for Database Administrators

By : April Sims
Book Image

Oracle Database 11g : Underground Advice for Database Administrators

By: April Sims

Overview of this book

Today DBAs are expected to deploy and manage large databases with quality service and little to no downtime. The DBA's main focus is on increasing productivity and eliminating idle redundancy throughout the enterprise. However, there is no magic set of best practices or hard and fast rules that DBAs need to follow, and this can make life difficult. But if DBAs follow some basic approaches and best practices, tasks can be performed more efficiently and effectively.This survival guide offers previously unwritten underground advice for DBAs. The author provides extensive information to illuminate where you fit in, and runs through many of the tasks that you need to be watchful of, extensively covering solutions to the most common problems encountered by newcomers to the world of Oracle databases.The book will quickly introduce you to your job responsibilities, as well as the skills, and abilities needed to be successful as a DBA. It will show you how to overcome common problems and proactively prevent disasters by implementing distributed grid computing—scalable and robust—with the ability to redeploy or rearchitect when business needs change. Reduce downtime across your enterprise by standardizing hardware, software, tools, utilities, commands, and architectural components.This book will also help you in situations where you need to install Oracle Database 11g or migrate to new hardware making it compliant with a Maximum Availability Architecture. By the end of this book you will have learned a lot and gained confidence in your abilities. You will be armed with knowledge as to which tools are best used to accomplish tasks while proactively moving towards an automated environment.
Table of Contents (14 chapters)
Oracle Database 11g—Underground Advice for Database Administrators
Credits
About the author
About the reviewers
Preface
Index

Gathering statistics


There is the Oracle-supplied package DBMS_STATS that will calculate statistics for a table (entire schema or the entire database), which is considered the replacement for the older (legacy) compute statistics command for calculating the cost of a query. Using the DBMS_STATS package will be your primary method for regulating statistics gathering on any database 10g and above, along with the startup initialization parameters of TIMED_STATISTICS and STATISTICS_LEVEL .

11g puts statistics gathering under the larger umbrella of Automatic Maintenance Tasks Management or AutoTask , which is used in conjunction with the resource manager so that jobs (like statistics gathering) are sure to complete successfully within the resource windows. These are the tasks automatically implemented:

  • Optimizer statistics gathering

  • Automatic Segment Advisor

  • SQL Tuning Advisor

The first set of automatic tasks is where we will start in this section-Optimizer Statistics Gathering, which calls the...