Archive for the ‘Blog’ Category
_gc_fusion_compression
We know that database blocks are transferred between the nodes through the interconnect, aka cache fusion traffic. Common misconception is that packet transfer size is always database block size for block transfer (Of course, messages are smaller in size). That's not entirely true. There is an optimization in the cache fusion code to reduce the packet size (and so reduces the bits transferred over the private network). Don't confuse this note with Jumbo ...
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 ...
Oracle Open World 2011 – My presentation on RAC topic
I will be talking about "Administering Parallel Execution in RAC" with demos on Sunday morning 9AM-10AM (session id 28060). This is part of IOUG RAC SIG presentation series. You would enjoy the content and demos I have prepared. I know, it is too early, but hoping to see you there! BTW, if you have attended my RAC Advanced Troubleshooting class series, please don't hesitate to introduce yourself when we meet. Session details: Session ID: 28060 Session Title: IOUG: ...
RAC hack session – Tuesday – July 11 2011
I will be conducting a 1-hour deep dive session about RAC LMS process (and about LGWR processes too if time permits) using advanced UNIX utilities. Read Tanel's blog entry for details: RAC hack session See you there!
1-Day Expert Oracle-centric Conference at MIT – 07/07/11 -virtual or physical
You probably aware of 1 day event happening on July 7th Thursday 9AM-5PM EDT (virtually and physically). I will be talking about advanced UNIX tools to debug issues. You can find details of 1-day event here Here is the outline of my presentation: Advanced tools and techniques in Unix environment - Riyaj Shamsudeen - 07/07/2011, 3:15pm - 4:00pm EDT Unix environments provides rich set of tools to debug performance ...
Advanced RAC Training
I will be delivering an intense, advanced 2-week RAC training seminar in Aug 22-26 and Sep 19-23 with numerous demos, dumps and scripts. We will meet 4 hours per day, in a virtual world, 8AM-12 Noon Pacific time for those two weeks. Tanel has written has a great blog post about this seminar series Advanced RAC training. If you like my presentations about RAC and performance tuning, you will love my ...
