Dynamic Performance Views

Oracle contains a set of underlying views that are maintained by the database server and accessible to the database administrator user SYS. These views are called dynamic performance views because they are continuously updated while a database is open and in use, and their contents relate primarily to performance.

Although these views appear to be regular database tables, they are not. These views provide data on internal disk structures and memory structures. You can select from these views, but you can never update or alter them.

1. X$         In memory structures (arrays)
2. V$         Views based on X$ structures
3. GV%     Global views: Same as V$ except include instance identifier as the first column
4. DBA_     All objects in the database
5. ALL_      All objects owned by the user and on which the user has been granted privileges
6. USER_   All objects owned by the user 
7. X$          In memory structures (arrays)
8. V$          Views based on X$ structures
9. GV%      Global views: Same as V$ except include instance identifier as the first column
10. DBA_     All objects in the database
11. ALL_      All objects owned by the user and on which the user has been granted privileges
12. USER_  All objects owned by the user