OCP-052考试题库汇总（11）-CUUG内部解答版

Which two are true about Optimizer Statistics?

A)They are gathered by the Manageability Monitor(MMON) background process.

B)They can be gathered by executing the PL/SQL procedures in the DBMS_STATES package.

C)They do not persist across instance restarts.

D)They can be used to determine the events on which a data instance waited.

E)They provide information to the Optimizer so that it can determine optimal execution plans for SQL statements.

F)They are automatically updated when DDL statements execute.

Answer: BE