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

Oracle Software
image
Write for Rampant
Publish with Rampant
Rampant News
Rampant Authors
Rampant Staff
 Phone
 800-766-1884
Oracle News
Oracle Forum
Oracle Tips
Articles by our Authors
Press Releases
SQL Server Books
image
image

Oracle 11g Books

Oracle tuning

Oracle training

Oracle support

Remote Oracle

STATSPACK Viewer

Privacy Policy

 

 
 

ss

Oracle Tips by Burleson 

Reducing disk I/O in UNIX

When using multiple blocksizes, the DBA is given additional control over the UNIX disk I/O sub-system.

The Oracle DBA understands the basic truths about UNIX disk I/O:

* Disk I/O is the largest component of Oracle response time. A reduction in disk I/O will always result in faster performance for that task.
* Creating larger data blocks allows Oracle to access more row data in a single I/O. Oracle9i supports multiple block sizes, and the Oracle9i DBA can move tables easily from one blocksize to a tablespace with another blocksize, thereby load-balancing disk I/O.
* The Oracle DBA has tools (in-place table reorgs, CTAS with order by) to allow easy table reorganization, and the DBA can use these tools to re-sequence table rows in the same order as the primary index to reduce disk I/O on index range scans. For more information, see Turning the Tables on Disk I/O, January 2000, at Oracle Magazine online (www.oramag.com).

So, how do we reduce disk I/O in UNIX? There are three generally accepted techniques for the DBA to reduce disk I/O:

* Tune SQL statements to retrieve data with a minimum of disk I/O - This is generally performed by finding large-table full-table scans and replacing the full-table scan with an index scan.
* Change the Oracle SGA - When we increase the shared_pool, large_pool, or db_cache_size, the resulting performance improvement is related to the reduction in disk I/O.
* Reorganize tables to reduce disk I/O – This is done by selectively moving tables to tablespaces with a different blocksize, and re-sequencing table rows into the primary key order.


The above is an excerpt from the "Oracle9i UNIX Administration Handbook" by Oracle press, authored by Donald K. Burleson.

 

Download your Oracle scripts now:

www.oracle-script.com

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 -2016 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
 

Hit Counter