Which two statements regarding a SQL profile are true? (Choose two)
A.
it is built by automatic Tuning Optimizer.
B.
It cannot be stored persistently in the data dictionary.
C.
It can be used by the query optimizer automatically.
D.
It can be created manually by using the CREATE PROFILE command
Explanation:
The query optimizer can sometimes produce inaccurate estimates about an attribute of a statement due to lack of information, leading to poor execution plans. Traditionally, users have corrected this problem by manually adding hints to the application code to guide the optimizer into making correct decisions. For packaged applications, changing application code is not an option and the only alternative available is to log a bu with the application vendor and wait for a fix. Automatic SQL Tuning deals with this problem with its SQL Profiling capability. The Automatic Tuning Optimizer creates a profile of the SQL statement called a SQL Profile, consisting of auxiliary statistics specific to that statement. The query optimizer under normal mode makes estimates about cardinality, selectivity, and cost that can smetimes be off by a significant amount resulting in poor execution plans .REF: Oracle(r) Database 10g Performance Guide , 12-2