1：查看、修改AWR報告快照數據的采樣間隔、保存策略
SQL> COL DBID FOR 999999999999
SQL> COL SNAP_INTERVAL FOR A26
SQL> COL RETENTION FOR A26
SQL> COL TOPNSQL FOR A10
SQL> select * from dba_hist_wr_control;
DBID SNAP_INTERVAL RETENTION TOPNSQL
------------- -------------------------- -------------------------- ----------
3990839260 +00000 01:00:00.0 +00014 00:00:00.0 DEFAULT
SQL>
SNAP_INTERVAL=+00000 01:00:00.0 表示采樣間隔是1小時
RETENTION=+00014 00:00:00.0 表示采樣數據保留期限是14天
如上所示，快照采樣間隔為1小時一次，快照數據保留14天。修改AWR的快照采樣間隔、保存配置，改為30分鍾采集一次快照數據，快照數據庫保留7天。如下所示：
SQL> COL DBID FOR 999999999999
SQL> COL SNAP_INTERVAL FOR A26
SQL> COL RETENTION FOR A26
SQL> select * from dba_hist_wr_control;
DBID SNAP_INTERVAL RETENTION TOPNSQL
------------- -------------------------- -------------------------- ----------
3990839260 +00000 01:00:00.0 +00014 00:00:00.0 DEFAULT
SQL> exec dbms_workload_repository.modify_snapshot_settings(interval=>30,retention=>7*24*60);
PL/SQL procedure successfully completed.
SQL> select * from dba_hist_wr_control;
DBID SNAP_INTERVAL RETENTION TOPNSQL
------------- -------------------------- -------------------------- ----------
3990839260 +00000 00:30:00.0 +00007 00:00:00.0 DEFAULT
SQL>
2：手動創建快照（Snapshots）
數據庫創建快照（Snapshots）一般是按Schedule定期創建的，默認一般一小時創建一個快照，只有當數據庫出現問題的時候，你才需要手工創建一個快照。以獲取那個時間段內的相關數據。
SQL> exec dbms_workload_repository.create_snapshot();
PL/SQL procedure successfully completed.
手工創建快照后，可以通過dba_hist_snapshot視圖查看創建的快照信息。
3：手動刪除快照（Snapshots）
--不指定DBID，默認當前實例DBID
SQL> exec dbms_workload_repository.drop_snapshot_range(61263,61274);
PL/SQL procedure successfully completed.
--指定DBID
SQL> exec dbms_workload_repository.drop_snapshot_range(7417,7429,3990839260);
PL/SQL procedure successfully completed.
4：創建基線（baseline）
一般來說當AWR自動維護快照時，如果定義過baseline，與baseline相關的快照不會被刪除，即使是過期的快照，這樣就相當於手動保留了一份統計數據的歷史信息，DBA可以在適當的時間將其與現有的快照進行對比，以生成相關的統計報表
SQL> COL BASELINE_NAME FOR A32;
SQL> SELECT DBID,BASELINE_NAME, START_SNAP_ID, END_SNAP_ID FROM DBA_HIST_BASELINE;
no rows selected
SQL> exec dbms_workload_repository.create_baseline(59806,59809,'20160726_07_11');
PL/SQL procedure successfully completed.
SQL> SELECT DBID,BASELINE_NAME, START_SNAP_ID, END_SNAP_ID FROM DBA_HIST_BASELINE;
DBID BASELINE_NAME START_SNAP_ID END_SNAP_ID
---------- -------------------------------- ------------- -----------
3990839260 20160726_07_11 59806 59809
SQL>
修改基線名稱
BEGIN
DBMS_WORKLOAD_REPOSITORY.rename_baseline(
old_baseline_name => 'old_name',
new_baseline_name => 'new_name');
END;
/
基線（baseline）是自Oracle 10g開始引入的，不過只包括了一些簡單的基線功能，創建一個基線允許保留指定范圍內的快照用於性能對比，與AWR保留策略無關，可以使用DBMS_WORKLOAD_REPOSITORY包來管理這個功能，在11g中，它被增強了。新增了許多功能。例如固定基線、移動窗口（Moving Window）基線等
5: 刪除基線（baseline）
首先查看基線設置,找到對應的baseline_name，然后刪除，過程如下所示：
SQL>SELECT * FROM DBA_HIST_BASELINE;
SQL> COL BASELINE_NAME FOR A32;
SQL> SELECT DBID,BASELINE_NAME, START_SNAP_ID, END_SNAP_ID FROM DBA_HIST_BASELINE;
DBID BASELINE_NAME START_SNAP_ID END_SNAP_ID
---------- -------------------------------- ------------- -----------
2179993557 20110112 12980 13004
2179993557 20100616 7959 7968
2179993557 20100818 9461 9485
2179993557 20101020 10964 10988
2179993557 20110119 13148 13172
2179993557 20101222 12476 12500
2179993557 20100602 7624 7632
SQL> exec dbms_workload_repository.drop_baseline('20110112',true);
PL/SQL procedure successfully completed.
刪除是如果指定了CASCADE參數為true，對應的snap也會被刪除。
6: 查看快照記錄信息
SELECT * FROM DBA_HIST_SNAPSHOT ORDER BY 1 DESC ;
SELECT SNAP_ID, DBID, INSTANCE_NUMBER, STARTUP_TIME,
BEGIN_INTERVAL_TIME, END_INTERVAL_TIME,
FLUSH_ELAPSED, SNAP_LEVEL, ERROR_COUNT
FROM WRM$_SNAPSHOT
WHERE STATUS = 0;
SELECT * FROM SYS.WRH$_ACTIVE_SESSION_HISTORY
7：導出、導入AWR快照數據
SQL> @?/rdbms/admin/awrextr.sql
SQL> @?/rdbms/admin/awrload.sql
8：刪除導入的AWR快照數據。
如果要刪除導入的awr數據，可以使用下面腳本進行刪除。
exec dbms_swrf_internal.unregister_database(dbid);
sql> exec dbms_swrf_internal.unregister_database(3990839260);
dbms_workload_repository：
可以刪除本地和其他數據庫的快照，可以選擇不同的快照來進行刪除。
dbms_swrf_internal：
只能對其他數據庫的快照來進行操作，會把整個快照unregister掉。
9：生成各種類型的AWR報告
Generating Various Types of AWR Reports
AWR reports can be generated by running various SQL scripts to satisfy various requirements. Each report is available in HTML or TXT format:
· awrrpt.sql
Displays various statistics for a range of snapshots Ids.
· awrrpti.sql
Displays statistics for a range of snapshot Ids on a specified database and instance.
· awrsqrpt.sql
Display statistics of a particular SQL statement for a range of snapshot Ids. Run
this report to inspect or debug the performance of a particular SQL statement.
· awrsqrpi.sql
Displays statistics of a particular SQL statement for a range of snapshot Ids on a specified SQL.
· awrddrpt.sql
Compares detailed performance attributes and configuration settings between two selected time periods.
· awrddrpi.sql
Compares detailed performance attributes and configuration settings between two selected time periods on a specific database and instance.
查看AWR報告里面某個具體SQL語句的執行計划
SQL> @?/rdbms/admin/awrsqrpt.sql
SQL> @?/rdbms/admin/awrsqrpi.sql
Workload Repository Views
The following workload repository views are available:
· V$ACTIVE_SESSION_HISTORY - Displays the active session history (ASH) sampled every second.
· V$METRIC - Displays metric information.
· V$METRICNAME - Displays the metrics associated with each metric group.
· V$METRIC_HISTORY - Displays historical metrics.
· V$METRICGROUP - Displays all metrics groups.
· DBA_HIST_ACTIVE_SESS_HISTORY - Displays the history contents of the active session history.
· DBA_HIST_BASELINE - Displays baseline information.
· DBA_HIST_DATABASE_INSTANCE - Displays database environment information.
· DBA_HIST_SNAPSHOT - Displays snapshot information.
· DBA_HIST_SQL_PLAN - Displays SQL execution plans.
· DBA_HIST_WR_CONTROL - Displays AWR settings.
參考資料：