Which two statements are true about the Automatic Database Diagnostic Monitor (ADDM)? (Choose two.)
A.The ADDM requires at least four AWR snapshots for analysis.
B.The ADDM runs after each AWR snapshot is collected automatically by MMON.
C.The results of the ADDM analysis are stored in the Automatic Workload Repository (AWR).
D.The ADDM analysis provides only diagnostic information but does not provide recommendations.
E.The ADDM calls other advisors if required, but does not provide recommendations about the advisors.
ADDM
每个 awr 快照被记录后，addm 就会自动运行，分析与最后两个快照对应的时段中的数据，addm 会主动监视实例。多数情况下，addm 会为检测到的问题提供解决方案，addm 可以检测到一些常见问题如下：
1.cpu 瓶颈
2.oracle net 连接管理问题
3.锁的竞争
4.IO 问题
5.一些数据库实例内存结构的大小不足
6.过载的 sql 语句
7.plsql 和 java 运行时间过长
8.检查点负载过高及原因(如日志文件过小)