I am currently working as junior Oracle DBA in a company.Now my team leads always tell me that I have to understand how SCN works and what I can do with the knowledge about SCN.So,are they really correct? I know SCN is system change number and a little more something about SCN but where can I find the exhaustive documentation and practice material related to SCN?
According to the Glossary from the Oracle Documentation
There is lots of info you can easily Google
Even the DBA StackExchange already has questions around the SCN
The best source for Oracle internals is generally the Oracle Concepts Guide.
In this case they have a pretty good description, including how it works as part of transaction control.