Call now: 252-767-6166  
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 







_db_block_cache_protect tips

Oracle Database Tips by Donald BurlesonNovember 16, 2015

Question:  What does the hidden parameter _db_block_cache_protect do?

Answer:  The _db_block_cache_protect parameter protects database blocks. If _db_block_cache_protect = true, then when a process needs to access a block in the buffer, it needs to make a special call to enable the access then disable it afterwards. The _db_block_cache_protect can add overhead and can harm system performance.
Oracle uses a special database algorithm to protect all modified blocks in the database memory. Any uncontrolled database writes inside the database memory area will be detected, protecting the disk from getting in memory corrupted blocks. After every successful disk read, the database block is checked in the database memory. The checksum information from the block header is compared with the memory checksum calculated on the fly. When they do not match, Oracle raises an error indicating a soft corrupted block, which will be reformatted and reused again.
Although in memory corruption detection is helpful, any in the memory corruption will crash the database instance. This parameter is hidden and by default always on.
Get the Complete
Oracle SQL Tuning Information 

The landmark book "Advanced Oracle SQL Tuning  The Definitive Reference"  is filled with valuable information on Oracle SQL Tuning. This book includes scripts and tools to hypercharge Oracle 11g performance and you can buy it for 30% off directly from the publisher.



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 -  2020

All rights reserved by Burleson

Oracle ® is the registered trademark of Oracle Corporation.



Oracle Training at Sea
oracle dba poster

Follow us on Twitter 
Oracle performance tuning software 
Oracle Linux poster