Examine the parameters for your database instance:
NAMETYPEVALUE
————————————————
optimizer_adaptive_reporting_onlybooleanFALSE
optimizer_capture_sql_plan_baselinesbooleanFALSE
optimizer_dynamic_samplinginteger2
optimizer_features_enablestring12.1.0.1
Which three statements are true about the process of automatic optimization by using statistics feedback? optimizer_features_enable executed repeatedly, for which the optimizer does not estimate cardinalities in the plan properly. The optimizer may misestimate cardinalities for a variety of reasons, such as missing or inaccurate statistics, or complex predicates. Whatever the reason for the misestimate, cardinality feedback may be able to help.
A.
The optimizer automatically changes a plan during subsequent execution of a SQL statement if there is a huge difference in optimizer estimates and
execution statistics.
B.
The optimizer can re optimize a query only once using cardinality feedback.
C.
The optimizer enables monitoring for cardinality feedback after the first execution of a query.
D.
The optimizer does not monitor cardinality feedback if dynamic sampling and multicolumn statistics are enabled.
E.
After the optimizer identifies a query as a re-optimization candidate, statistics collected by the collectors are submitted to the optimizer.