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

Data Recovery Adviser


Oracle has the ability to create the script to repair the database. This is known as the Data Recovery Adviser (DRA). If you need to introduce your own corruption for testing purposes, you could research on the Internet for examples. The following example is how the DRA was used to restore a corrupted datafile.

I removed all backups before starting this scenario. This means that the recovery came from the redo and any archived logs. Cool! See the restoration from the redo section for more about this.

  1. RMAN backup command detects a problem and it doesn't mention the word "corrupt".

    Notice that the alert log has the same date time stamp as the RMAN session, which detected the problem.

  2. Using RMAN, I start investigating to see what RMAN knows about the problem.

  3. Using RMAN, I ask the DRA what I should do about this problem—this is known as the advise failure command.

The contents of the repair script are included below:

RMAN>
 # restore and recover datafile
   sql 'alter database...