Which three are true about the Automatic Workload Repository (AWR)?
A)AWR data is stored in the SYSTEM tablespace.
B)By default, AWR snapshots are taken every 60 minutes.
C)It is the foundation for the self-managing infrastructure.
D)The taking of AWR snapshots cannot be disabled.
E)Its collection level is determined by the value of the STATISTICS_LEVEL database parameter.
Answer: BCE
赵：
A 选项，AWR 是存放在 SYSAUX 中的表，属于 SYSMAN 模式
B 选项，MMON 进程将 AWR 统计信息作为快照保存到 AWR，默认 60 分钟保存一次，保存 8 天。
D 选项，The taking of AWR snapshots cannot be disabled. AWR 不能禁止，是错的，basic 就禁用了
E 选项，AWR 的收集级别取决于 STATISTICS_LEVEL，BASIC 几乎禁用全部信息，即禁用 AWR 的信息收集;TYPICAL 收集正常调整需要的信息，不收集对性能有不良影响的信息;ALL 收集全部与 SQL 执行有关的信息
