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.
答案：（A、E）
解析：
OPTIMIZER_USE_SQL_PLAN_BASELINES = {true | false}
该参数决定是否使用存储在SQL Management Base中的SQL plan baseline.
true, SQL语句被编译的时候,优化器会查看SQL plan baseline, 如果在SQL Management Base中找到了一个基线
则优化器会计算基线中每个执行计划的成本,并选择成本最低的一个