In your database,the STATISTICS_LEVEL initialization parameter is set to BASIC.What is the impact of this setting?
A-The optimizer statistics are collected automatically.
B-Only the timed operating system(OS)statistics and plan execution statistics are collected.
C-The Oracle server dynamically generates the necessary statistics on tables as part of query optimization.
D-The snapshots for the Automatic Workload Repository(AWR)are not generated automatically.
E.Snapshots cannot be collected manually by using DBMS_WORKLOAD_REPOSITORY PACKAGE.
使用AWR收集数据库统计表是默认可用的，它是由初始化参数statistics_level控制的。初始化参数statics_level应该被设置成typical或者all，这样才能开启AWR特性收集统计表。默认值是typical。如果将statics_level值设置为basic,将会禁用ORACLE数据库的许多特性，包括awr,ORACLE不建议你这么做。
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