Proactive Maintenance

1.执行统计分析

    SQL> create table hr.a tablespace data01 as select * from hr.employees;

    SQL> select num_rows from dba_tables where owner='HR' and table_name='A';  --执行结果为空

    SQL> exec dbms_stats.gather_table_stats('HR','A');

   再次查询：

   SQL> select num_rows from dba_tables where owner='HR' and table_name='A'; --结果返回107行，统计成功。

2.执行awr及addm

   a.制造负载

   SQL> create table hr.b tablespace users as select * from source$;

   SQL> create table hr.c tablespace users as select * from hr.b;

   SQL> select b.line,count(*)  from hr.b,hr.c group by b.line;

 b.抓取若干快照

     SQL> exec dbms_workload_repository.create_snapshot();

     SQL> exec dbms_workload_repository.create_snapshot();

     SQL> select snap_id from dba_hist_snapshot;

  C.执行awr

    SQL>@?/rdbms/admin/awrrpt.sql

  D.执行addm

    SQL>@?/rdbms/admin/addmrpt.sql