Troubleshooting LMS processes
This was created circa July 2011. Enjoy. [wpvideo mabMGh2o]
SCN – What, why, and how?
In this blog entry, we will explore the wonderful world of SCNs and how Oracle database uses SCN internally. We will also explore few new bugs and clarify few misconceptions about SCN itself. What is SCN? SCN (System Change Number) is a primary mechanism to maintain data consistency in Oracle database. SCN is used primarily in the following areas, of course, this is not a complete list: Every redo record has an SCN version of the redo record ...
GC cr disk read
You might encounter RAC wait event 'gc cr disk read' in 11.2 while tuning your applications in RAC environment. Let's probe this wait event to understand why a session would wait for this wait event. Understanding the wait event Let's say that a foreground process running in node 1, is trying to access a block using a SELECT statement and that block is not in the local cache. To maintain the read consistency, foreground process will require ...
RMOUG 2012 – Hello Denver!
On February 14-16, I’ll be at the Colorado Convention Center in Denver, Colorado for RMOUG’s Training Days Conference. This is the largest regional Oracle User Conference in North America and attracts presenters from all around the country and the globe. I’ll be presenting: Presentation Name: Troubleshooting RAC Background Process Abstract: RAC background process performance is critical to keep the application performance. This session will ...
Troubleshooting ‘DFS lock handle’ waits
Waits for 'DFS lock handle' can cause massive performance issues in a busy RAC cluster. In this blog entry, we will explore the DFS lock handle wait event, and understand how to troubleshoot the root cause of these waits. I am also going to use locks and resources interchangeably in this blog, but internally, they are two different types of structures. A little background DFS (stands for Distributed File System) is an ancient name, associated ...
