Oracle Training Oracle Support Development Oracle Apps

 E-mail Us
 Oracle Articles
New Oracle Articles

 Oracle Training
 Oracle Tips

 Oracle Forum
 Class Catalog

 Remote DBA
 Oracle Tuning
 Emergency 911
 RAC Support
 Apps Support
 Oracle Support

 SQL Tuning

 Oracle UNIX
 Oracle Linux
 Remote s
 Remote plans
 Application Server

 Oracle Forms
 Oracle Portal
 App Upgrades
 SQL Server
 Oracle Concepts
 Software Support

 Remote S


 Consulting Staff
 Consulting Prices
 Help Wanted!


 Oracle Posters
 Oracle Books

 Oracle Scripts

Don Burleson Blog 







Linda Webb

Got breaking Oracle news?    Burleson Consulting Oracle News

Click here for more Oracle News Headlines


Lawson speaks on Oracle parallel query

In this excellent article by Chris Lawson, author of the bestselling “The Art and Science of Oracle Performance Tuning”, we see an excellent discussion on tuning with Oracle Parallel query (OPQ):


Most Oracle professionals know that setting parallelism a the system level (parallel_automatic_tuning parameter), or session-level parallelism (the alter session force parallel query command) can be dangerous because the cost-based SQL optimizer will assign a smaller cost to full-table scans, causing index to cease being used.  Most Oracle folks only invoke parallelism at the SQL-level, using the parallel hint (e.g. select /*+ parallel (c, 31) */).  Lawson notes:


Our experiments showed that forcing parallelism at the session level causes extra extents to be used for each slave, whether the Insert or Merge command is used.


The extra extents may be a problem only when extent sizes are way too high. In addition, if you don’t alter your session to force parallelism, this may never be a problem for you.


Oracle Training at Sea
oracle dba poster

Follow us on Twitter 
Oracle performance tuning software 
Oracle Linux poster


Burleson is the American Team

Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals.  Feel free to ask questions on our Oracle forum.

Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise. All legitimate Oracle experts publish their Oracle qualifications.

Errata?  Oracle technology is changing and we strive to update our BC Oracle support information.  If you find an error or have a suggestion for improving our content, we would appreciate your feedback.  Just  e-mail:  

and include the URL for the page.


Burleson Consulting

The Oracle of Database Support

Oracle Performance Tuning

Remote DBA Services


Copyright © 1996 -  2017

All rights reserved by Burleson

Oracle ® is the registered trademark of Oracle Corporation.

Remote Emergency Support provided by Conversational