Here is an Interesting topic about FAST DUAL and Full Table Scan on Dual table with some example about how not to play with Oracle Data Dictionary Objects.
http://www.orafaq.com/forum/mv/msg/173068/515910/136607/#msg_515910
Happy reading….
Sriram 🙂
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Sriram Sanka
Hi there, This is SCP Ranga Rao Sanka working as (A product Manager/Principal DBA)., I have a broad range of Experience in Administration and Implementation in the areas of Database, Cloud, and Other Servers. I am one of the moderators at ORAFAQ. The primary purpose of this blog is to share knowledge.
All the code snippets, URLs, and everything in this blog are from My experience, My Learnings from different websites & forums. so please test the posts on your testing Environment first.
The experiences, Test cases, views, and opinions, etc., expressed on this website are my own and do not reflect the views or opinions of my employer.
This site is independent of and does not represent Oracle Corporation in any way. Oracle does not officially sponsor, approve, or endorse this site or its content. Product and company names mentioned on this website may be the trademarks of their respective owners. I am not responsible for any kind of Damage or any legal activities.
Sriram Sanka 
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