我寫的SQL調優專欄：https://blog.csdn.net/u014427391/article/category/8679315
對於局部的，比如某個頁面列表sql，我們可以使用Oracle的執行計划進行sql調優，但是對於整個系統來說，你可以知道哪些sql比較耗時？當然可以通過查Oracle的共享池得到，不過Oracle系統本身就提供了幾種性能分析報告，比如AWR、ASH、ADDM、AWRDD等等報告，本博客介紹一下ADDM性能分析報告
ADDM全稱是Automatic Database Diagnostic Monitor，是Oracle一個實現性能自我診斷的最佳利器。它依賴於AWR，也就是說ADDM要診斷，必要要有診斷的依據。在Oracle中，這個診斷依據就是Oracle AWR，因為Oracle AWR會定期的收集整個數據庫在運行期間的性能統計數據。
一、ADDM報告生成
繼之前AWR、ASH方面的博客之后，https://smilenicky.blog.csdn.net/article/details/89414432，https://smilenicky.blog.csdn.net/article/details/89419185，我再寫一篇ADDM方面的博客：
1.1 工具選擇
對於Oracle數據庫可以使用sqlplus或者plsql developer客戶端軟件
sqlplus 使用
可以使用sqlplus工具登錄
進入數據庫
sqlplus / as sysdba
查看用戶
show parameter db_name
用登錄之后才可以使用
plsql developer使用
plsql developer也可以使用，登錄之后，選擇文件(File)->新建(New)->命令窗口(Command Window)
1.2 自動創建快照
開始壓測后執行
exec DBMS_WORKLOAD_REPOSITORY.CREATE_SNAPSHOT ();
可以通過dba_hist_wr_control查看當前的配置情況，當前awr為每1小時做一次數據快照，保留時間為8天。
select * from dba_hist_wr_control;
修改配置，每隔30分鍾收集一次，保存1天
execute dbms_workload_repository.modify_snapshot_settings(interval=>30,retention=>14000);
關閉自動收集
SQL>exec dbms_workload_repository.modify_snapshot_settings (interval=>0,retention=>24*60);
1.3 手工創建快照
除了自動創建快照，也可以手工創建快照
select dbms_workload_repository.create_snapshot() from dual;
1.4 ADDM報告生成
對於sqlplus客戶端的可以使用
@?/rdbms/admin/addmrpt.sql
對於plsql客戶端，我用絕對路徑去執行，@?的命令找不到文件
這個要根據自己的Oracle安裝路徑去修改，例如：
@D:/oracle/product/11.1.0/db_1/RDBMS/ADMIN/addmrpt.sql
（1）快照開始id
Enter value for begin_snap:418
要根據日志打印的快照id范圍來填，所以我可以填寫：418
（2）快照結束id
Enter value for end_snap:420
要根據日志打印的快照id范圍來填，所以我可以填寫：420
（3）ADDM報告名稱
Enter value for report_name
填寫ADDM報告的名稱，我可以填寫addm_20190421.html，然后在打印的日志里有文件保存的路徑：，比如：D:\oracle\product\11.2.0\dbhome_1\RDBMS\ADMIN\addm.html
SQL> @D:/oracle/product/11.2.0/dbhome_1/RDBMS/ADMIN/addmrpt.sql
Current Instance
~~~~~~~~~~~~~~~~
DBID DB_NAME INST_ INST_NAME
---------- ------------ ----- ------------
1525762377 ORCL 1 orcl
Cannot SET TRIMSPOOL
Cannot SET UNDERLINE
Instances in this Workload Repository schema
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
DBBID INSTT DBB_NAME INSTT_NAME HOST
------------ ----- ------------ ------------ ------------
* 1525762377 1 ORCL orcl PC-201508171
906
Using 1525762377 for database Id
Using 1 for instance number
PL/SQL procedure successfully completed
dbid
---------
1525762377
inst_num
---------
1
PL/SQL procedure successfully completed
inst_num
---------
1
dbid
---------
1525762377
max_snap_time
---------
18/04/2019
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 <return> without
specifying a number lists all completed snapshots.
Listing the last 3 days of Completed Snapshots
INST_NAME DB_NAME SNAP_ID SNAPDAT LV
------------ ------------ -------- ------------------ --
orcl ORCL 417 16 Apr 2019 00:00 1
orcl ORCL 418 16 Apr 2019 19:48 1
orcl ORCL 419 16 Apr 2019 21:00 1
orcl ORCL 420 16 Apr 2019 22:00 1
orcl ORCL 421 16 Apr 2019 23:00 1
orcl ORCL 422 17 Apr 2019 21:20 1
orcl ORCL 423 17 Apr 2019 22:00 1
orcl ORCL 424 17 Apr 2019 23:00 1
orcl ORCL 425 18 Apr 2019 00:00 1
orcl ORCL 426 18 Apr 2019 21:26 1
orcl ORCL 427 18 Apr 2019 22:00 1
11 rows selected
dbid
---------
1525762377
inst_num
---------
1
max_snap_time
---------
18/04/2019
Specify the Begin and End Snapshot Ids
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Begin Snapshot Id specified: 418
End Snapshot Id specified: 420
PL/SQL procedure successfully completed
bid
---------
418
eid
---------
420
PL/SQL procedure successfully completed
inst_num
---------
1
dbid
---------
1525762377
bid
---------
418
eid
---------
420
Cannot SET TRIMSPOOL
Cannot SET UNDERLINE
Specify the Report Name
~~~~~~~~~~~~~~~~~~~~~~~
The default report file name is addmrpt_1_418_420.txt. To use this name,
press <return> to continue, otherwise enter an alternative.
Using the report name addm.html
Running the ADDM analysis on the specified pair of snapshots ...
bid
---------
418
eid
---------
420
inst_num
---------
1
dbid
---------
1525762377
task_name
---------
TASK_953
Generating the ADDM report for this analysis ...
Started spooling to D:\oracle\product\11.2.0\dbhome_1\RDBMS\ADMIN\addm.html
ADDM Report for Task 'TASK_953'
-------------------------------
Analysis Period
---------------
AWR snapshot range from 418 to 420.
Time period starts at 16-APR-19 07.48.09 PM
Time period ends at 16-APR-19 10.00.20 PM
Analysis Target
---------------
Database 'ORCL' with DB ID 1525762377.
Database version 11.2.0.1.0.
ADDM performed an analysis of instance orcl, numbered 1 and hosted at
PC-201508171906.
Activity During the Analysis Period
-----------------------------------
Total database time was 57 seconds.
The average number of active sessions was .01.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
There are no findings to report.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Additional Information
----------------------
Miscellaneous Information
-------------------------
There was no significant database activity to run the ADDM.
The database's maintenance windows were active during 99% of the analysis
period.
task_name
---------
TASK_953
Stopped spooling to D:\oracle\product\11.2.0\dbhome_1\RDBMS\ADMIN\addm.html
End of Report
Report written to addm.html.
二、ADDM報告性能分析
ADDM性能報告是從數據庫的整體配置和局部SQL方面給出建議，閱讀時候按FINDING1，FINDING2，...，的順序閱讀就好
下面的圖來自《收獲，不止SQL優化》一書：
