The OPTIMIZER_USE_PLAN_BASELINES parameter is set to TRUE. The optimizer generates a
plan for a SQL statement but does not find a matching plan in the SQL plan baseline. Which two
operations are performed by the optimizer in this scenario? (Choose two.)
A.
The optimizer adds the new plan to the plan history.
B.
The optimizer selects the new plan for the execution of the SQL statement.
C.
The optimizer adds the new plan to the SQL plan baseline as an accepted plan.
D.
The optimizer adds the new plan to the SQL plan baseline but not in the ENABLED state.
E.
The optimizer costs each of the accepted plans in the SQL plan baseline and picks the one with
the lowest cost.
1 . Each time the database compiles a SQL statement, the optimizer does the following:
Uses a cost-based search method to build a best-cost plan
Tries to find a matching plan in the SQL plan baseline
Does either of the following depending on whether a match is found:
* If found, then the optimizer proceeds using the matched plan
* If not found, then the optimizer evaluates the cost of each accepted plan in the SQL plan baseline and selects the plan with the lowest cost
2. If a plan baseline exists, then the optimizer behavior depends on whether the newly generated plan is in the plan baseline:
If the new plan is in the baseline, then the database executes the statement using the found plan.
If the new plan is not in the baseline, then the optimizer marks the newly generated plan as unaccepted and adds it to the plan history. Optimizer behavior depends on the contents of the plan baseline: