Call for Oracle support & training (800) 766-1884
Free Oracle Tips

Home
Corporate Oracle Training
Custom Oracle Training
Oracle New Features Training
Advanced Oracle DBA Classes
Oracle Tuning Courses
Oracle Tips & Tricks
Oracle Training Links
Oracle Training Links
Oracle Training Links

We are top for USA Oracle Training Clients

 

Free Oracle Tips


 
HTML Text AOL

Free Oracle App Server Tips


 
HTML Text

Oracle support

Oracle training

Oracle tuning

Rednecks!

Remote Oracle

Custom Oracle Training

 

   
  Oracle Tips by Burleson

OCP Instructors Guide for Oracle DBA Certification

Chapter 7 - Tuning and Performance

Data Segment Compression

Data compression in Oracle9i Release 2 is performed at the block level.  Administrators are able to compress entire tables and specific table partitions.  The COMPRESS attribute can be specified in the CREATE TABLE, CREATE TABLESPACE and CREATE TABLESPACE. PARTITION statements.  Block compression works by eliminating repeating column values. The more repeating values the columns have the greater the compression ratio becomes.  

We recently learned that compression is performed at the block level in Oracle.  This means that as the number of repetitious values per block increases so does its compression ratio.  Administrators are able to achieve higher compression ratios by sorting the rows on a column that has a poor cardinality (high number of repeating values). CREATE TABLE……SELECT * FROM…… ORDER BY low_cardinality_column can be used to ensure as many repeating values fall in the same block as possible.   Flat file data being loaded by the Oracle load utility can be sorted using an operating system sort utility to achieve the same result.        
    


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
 

http://www.rampant-books.com/book_2003_2_OCP_print.htm


Download your Oracle scripts now:

www.oracle-script.com

The definitive Oracle Script collection for every Oracle professional DBA

 
 
 

Oracle performance tuning book

 

 

Oracle performance tuning software

 
Oracle performance tuning software
 
Oracle performance Tuning 10g reference poster
 
Oracle training in Linux commands
 
Oracle training Excel
 
 
 
 

 

email BC:


Copyright © 1996 -  2014 by Burleson Inc. All rights reserved.

Oracle® is the registered trademark of Oracle Corporation.