[오라클] V$ object 와 object 의 차이점

Oracle FAQ's

V$% views return data from memory structures. Data is lost when the instance is restarted.
DBA_% tables return data from the database's data dictionary (SYSTEM tablespace). Data persists across instance restarts.

v$ view는 memory structure data를 보여주며, dba_ table(?)은 system tablespace 상의 data dictoinary data를 보여줍니다. 10g에서 awr 관련 view들이 만들어져서 dba_hist view 등에서 memory structure statistic data를 system tablespace에 저장해서 보여주기도 하죠.
다음의 HP's oracle blog에는 좀더 자세한 내용이 실려 있습니다..
HP's Oracle Blog

V$ & DBA_
Static Data Dictionary Views and Dynamic Performance Views are the core of database administration. They are of crucial importance. Whoever wants to learn Oracle database administration has to get familiar with these views.
The Data Dictionary tables contain meta data on objects, privileges, roles, users etc.
Whenever you issue DML statements Oracle consults its data dictionary to make sure a table is there, it has the right columns and you have privileges on it. And whenever you issue DDL statements Oracle updates its data dictionary.
All information needed by an instance on its database is kept in the data dictionary. Except some storage related information which is in the datafile headers and some information in controlfile and spfile which is needed at instance startup.
At runtime the oracle instance stores information about itself, about its CPU, memory or I/O performance, wait statistics and everything else which is going on at the instance in dynamic performance tables. Dynamic performance tables are non persistent. You can’t see past instance startup. After shutdown or instance crash all information contained in dynamic performance tables is lost. *1)
Through static dictionary views users can get at information kept in data dictionary tables.
And through dynamic performance views users can look at non persistent runtime information contained in dynamic performance tables.
But why are those views that important, you might ask? All information necessary for database administration can be found in those static dictionary views. And basically all information necessary for instance diagnostic and tuning can be obtained through those dynamic performance views at runtime.
Of course, GUI tools like Enterprise Manager or SQL Developer offer the same information
in a more user friendly manner. But all those GUI tools rely on static dictionary views and dynamic performance views.
As a DBA you will likely get into situations where there is no GUI tools available. At times you will be alone with your SQL*Plus skills. Your mastery of data dictionary and performance views will make all the difference!