一、 AWR使用
SQL>@?/rdbms/admin/awrrpt.sql

Specify the Report Type
~~~~~~~~~~~~~~~~~~~~~~~
Would you like an HTML report, or a plain text report?
Enter 'html' for an HTML report, or 'text' for plain text
Defaults to 'html'
输入 report_type 的值:  
Type Specified:  html
Specify the number of days of snapshots to choose from
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Entering the number of days (n) will result in the most recent
(n) days of snapshots being listed.  Pressing without
specifying a number lists all completed snapshots.
输入 num_days 的值:  1
Listing the last day's Completed Snapshots
                                                        Snap
Instance     DB Name        Snap Id    Snap Started    Level
------------ ------------ --------- ------------------ -----
orcl10g      ORCL10G            142 03 7月  2009 08:11     1
                                143 03 7月  2009 09:00     1
                                144 03 7月  2009 10:00     1
                                145 03 7月  2009 11:00     1
                                146 03 7月  2009 12:01     1
Specify the Begin and End Snapshot Ids
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
输入 begin_snap 的值:  142
Begin Snapshot Id specified: 142
输入 end_snap 的值:  146
End   Snapshot Id specified: 146
Specify the Report Name
~~~~~~~~~~~~~~~~~~~~~~~
The default report file name is awrrpt_1_142_146.html.  To use this name,
press to continue, otherwise enter an alternative.
输入 report_name 的值:  /home/oracle/awrrpt_1_142_146.html
Report written to /home/oracle/awrrpt_1_142_146.html

二、AWR管理
（1）关闭awr：
SQL> exec dbms_workload_repository.modify_snapshot_settings(interval=>0);
说明：把interval设为0则已经关闭awr功能。
验证：
SQL> select * from dba_hist_wr_control;

      DBID    SNAP_INTERVAL        RETENTION          TOPNSQL
----------    ------------------- ------------------- ----------
 450641661    +40150 00:00:00.0   +00008 00:00:00.0   DEFAULT  

（2）打开awr:
SQL> exec dbms_workload_repository.modify_snapshot_settings(interval=>30, retention=>5*24*60);

说明：收集间隔时间为30分钟一次，并且保留5天时间（单位都是分钟）
如果执行时报错：
SQL> exec dbms_workload_repository.modify_snapshot_settings(interval=>30, retention=>5*24*60);
BEGIN dbms_workload_repository.modify_snapshot_settings(interval=>30, retention=>5*24*60); END;
*
ERROR at line 1:
ORA-13541: system moving window baseline size (691200) greater than retention (432000)
ORA-06512: at "SYS.DBMS_WORKLOAD_REPOSITORY", line 89
ORA-06512: at "SYS.DBMS_WORKLOAD_REPOSITORY", line 137
ORA-06512: at line 1

原因是系统设置的baseline size值（691200）大于此时设置的retention（432000），那么此时有两种方法解决：
方法1：增大retention值，也就是增大保存天数，比如修改为：
SQL> exec dbms_workload_repository.modify_snapshot_settings(interval=>30, retention=>9*24*60);

PL/SQL procedure successfully completed.

验证：
SQL> select * from dba_hist_wr_control;

      DBID    SNAP_INTERVAL        RETENTION          TOPNSQL
----------    ------------------- ------------------- ----------
450641661     +00000 00:30:00.0    +00009 00:00:00.0   DEFAULT

（3）查看快照记录：
select * from sys.wrh$_active_session_history