Call now: 252-767-6166  
Oracle Training Oracle Support Development Oracle Apps

 
 Home
 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
 Analysis
 Design
 Implementation
 Oracle Support


 SQL Tuning
 Security

 Oracle UNIX
 Oracle Linux
 Monitoring
 Remote s
upport
 Remote plans
 Remote
services
 Application Server

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

 Remote S
upport  
 Development  

 Implementation


 Consulting Staff
 Consulting Prices
 Help Wanted!

 


 Oracle Posters
 Oracle Books

 Oracle Scripts
 Ion
 Excel-DB  

Don Burleson Blog 


 

 

 


 

 

 
 
 

Inserts become slow as table grows

Oracle Database Tips by Donald BurlesonJuly 29, 2015


Question:  I have a insert job that runs hourly.  At first, I was seeing an insert rate of 3,000 rows per minute, but now that the table has over a million rows, the insert rate has slowed to a crawl.  It seems like as the table grows larger, the inserts run slower.  What can cause a slowdown in insert speed as a table grows?

Answer:  Oracle inserts can slow down for a multitude of reasons as a table grows. First, see my notes on Oracle insert performance tuning.   Here are the most common reasons for slowness of inserts:

  • Stale statistics - Do this first, re-analyze the table and ALL indexes on the table:

EXEC DBMS_STATS.gather_table_stats('SCOTT', 'EMPLOYEES');
EXEC DBMS_STATS.gather_index_stats('SCOTT', 'EMPLOYEES_PK');

  • Freelist issues - Tables that re-user free blocks can see issues with the overhead of re-using data blocks.  To avoid this, use INSERT APPEND (only of you are doing an insert without a VALUES clause).
  • NEXT extent size - If you have a tint NEXT extent size, you may see delays each time that Oracle extends the table and index.  It's best of you pre-allocate the space.
  • Index fragmentation - In rare cases, fragmented indexes can contribute to slow insert performance.  To see, try rebuilding your indexes.

Also, you might have issues with contention for multiple concurrent inserts, and check to see if you have ASSM contention (ASSM does not always perform well under very high concurrent DML loads).  If so, redefine the table with enough freelists and freelist groups for the target tables and associated indexes. 


 

 

��  
 
 
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 -  2020

All rights reserved by Burleson

Oracle ® is the registered trademark of Oracle Corporation.