Oracle Consulting Oracle Training Oracle Support Development
Oracle Books
SQL Server Books
IT Books
Job Interview Books
Rampant Horse Books
911 Series
Pedagogue Books

Oracle Software
Write for Rampant
Publish with Rampant
Rampant News
Rampant Authors
Rampant Staff
Oracle News
Oracle Forum
Oracle Tips
Articles by our Authors
Press Releases
SQL Server Books

Oracle 11g Books

Oracle tuning

Oracle training

Oracle support

Remote Oracle


Privacy Policy


  Oracle Tips by Burleson

OCP Instructors Guide for Oracle DBA Certification

Chapter 5 - Oracle Database Objects

Rollback Segments and Users – Who’s Using What?

The output from the query below will tell you what rollback segment a user is using.  The output provides the rollback segment name, Oracle account and operating system account. This is a good statement to use when an active transaction is preventing a rollback segment from being taken offline or shrinking back to its optimal size.

select osuser o, username u, segment_name s, substr(sa.sql_text,1,200) txt
from v$session s, v$transaction t, dba_rollback_segs r, v$sqlarea sa

The statement provides the OS user account, Oracle account, the rollback (or undo) segment name and the statement that is currently executing.

Oracle9i - Database Managed Undo Segments

You don’t have to be an Oracle expert to know that rollback segments can be "somewhat troublesome." Out of space conditions, contention, poor performance and the perennial favorite "snap shot too old" errors have been plaguing Oracle database administrators for over a decade. Oracle finally decided that the database could probably do a better job of managing before images of data than we could.

The above text is an excerpt from:

OCP Instructors Guide for Oracle DBA Certification
A Study Guide to Advanced Oracle Certified Professional Database
Administration Techniques

ISBN 0-9744355-3-8

by Christopher T. Foot

Download your Oracle scripts now:

The definitive Oracle Script collection for every Oracle professional DBA

Linux Oracle commands syntax poster

ION Oracle tuning software

Oracle data dictionary reference poster

Oracle Forum

BC Oracle consulting support training

BC remote Oracle DBA   



 Copyright © 1996 -2017 by Burleson. All rights reserved.

Oracle® is the registered trademark of Oracle Corporation. SQL Server® is the registered trademark of Microsoft Corporation. 
Many of the designations used by computer vendors to distinguish their products are claimed as Trademarks