2、Which two are true about Optimizer Statistics?
❑ A) They do not persist across Instance restarts.
❑ B) They are automatically updated when DDL statements execute.
❑ C) They are gathered by the Manageability Monitor (MMON) background process.
❑ D) They can be gathered by executing the PL/SQL procedures in the DBMS_STATS package.
❑ E) They can be used to determine the events on which a database instance waited.
❑ F) They provide Information to the Optimizer so that it can determine optimal execution plans for SQL statements.
• Answer:DF
