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 support
 Remote plans
 Remote services
 Application Server
 Applications
 Oracle Forms
 Oracle Portal
 App Upgrades
 SQL Server
 Oracle Concepts
 Software Support
 Remote Support  
 Development  
 Implementation


 Consulting Staff
 Consulting Prices
 Help Wanted!

 


  Oracle Posters
 Oracle Books
  Oracle Scripts
 Ion
 Excel-DB  

Don Burleson Blog 


 

 

 


 

 
 

 
 

Find gaps in Oracle sequences

Oracle Database Tips by Donald BurlesonOctober 26, 2015

 

Oracle sequences allow the DBA to insert unique sequence numbers for artificial keys and maintain an auto-numbering system.

 

While Oracle has tools to detect sequencing gaps in archived redo logs (the v$archive_gap view), we have to write own own SQL to detect gaps in user-defined Oracle sequences.

 

This blog has an interesting use of the Oracle LEAD and LAG functions for SQL to detect gaps in Oracle sequence numbers, very creative:

 

SQL> WITH aquery AS
2 (SELECT measurement_idafter_gap,
3 LAG(measurement_id,1,0) OVER (ORDER BY measurement_id) before_gap
4 FROM sensor_data)
5 SELECT
6 before_gap, after_gap
7 FROM
8 aquery
9 WHERE
10 before_gap != 0
11 AND
12 after_gap - before_gap > 1
13 ORDER BY
14 before_gap;



BEFORE_GAP AFTER_GAP

---------- ----------
2 4
5 7

 

 

 
��  
 
 
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.