我写的SQL调优专栏：https://blog.****.net/u014427391/article/category/8679315
对于局部的，比如某个页面列表sql，我们可以使用Oracle的执行计划进行sql调优，但是对于整个系统来说，你可以知道哪些sql比较耗时？当然可以通过查Oracle的共享池得到，不过Oracle系统本身就提供了几种性能分析报告，比如AWR、ASH、ADDM、AWRDD等等报告，本博客介绍一下ADDM性能分析报告
ADDM全称是Automatic Database Diagnostic Monitor，是Oracle一个实现性能自我诊断的最佳利器。它依赖于AWR，也就是说ADDM要诊断，必要要有诊断的依据。在Oracle中，这个诊断依据就是Oracle AWR，因为Oracle AWR会定期的收集整个数据库在运行期间的性能统计数据。
一、ADDM报告生成
继之前AWR、ASH方面的博客之后，https://smilenicky.blog.****.net/article/details/89414432，https://smilenicky.blog.****.net/article/details/89419185，我再写一篇ADDM方面的博客：
1.1 工具选择
对于Oracle数据库可以使用sqlplus或者plsql developer客户端软件
sqlplus 使用
可以使用sqlplus工具登录
进入数据库
sqlplus / as sysdba
查看用户
show parameter db_name
用登录之后才可以使用
plsql developer使用
plsql developer也可以使用，登录之后，选择文件(File)->新建(New)->命令窗口(Command Window)
1.2 自动创建快照
开始压测后执行
exec DBMS_WORKLOAD_REPOSITORY.CREATE_SNAPSHOT ();
可以通过dba_hist_wr_control查看当前的配置情况，当前awr为每1小时做一次数据快照，保留时间为8天。
select * from dba_hist_wr_control;
修改配置，每隔30分钟收集一次，保存1天
execute dbms_workload_repository.modify_snapshot_settings(interval=>30,retention=>14000);
关闭自动收集
SQL>exec dbms_workload_repository.modify_snapshot_settings (interval=>0,retention=>24*60);
1.3 手工创建快照
除了自动创建快照，也可以手工创建快照
select dbms_workload_repository.create_snapshot() from dual;
1.4 ADDM报告生成
对于sqlplus客户端的可以使用
@?/rdbms/admin/addmrpt.sql
对于plsql客户端，我用绝对路径去执行，@?的命令找不到文件
这个要根据自己的Oracle安装路径去修改，例如：
@D:/oracle/product/11.1.0/db_1/RDBMS/ADMIN/addmrpt.sql
（1）快照开始id
Enter value for begin_snap:418
要根据日志打印的快照id范围来填，所以我可以填写：418
（2）快照结束id
Enter value for end_snap:420
要根据日志打印的快照id范围来填，所以我可以填写：420
（3）ADDM报告名称
Enter value for report_name
填写ADDM报告的名称，我可以填写addm_20190421.html，然后在打印的日志里有文件保存的路径：，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报告性能分析
ADDM性能报告是从数据库的整体配置和局部SQL方面给出建议，阅读时候按FINDING1，FINDING2，...，的顺序阅读就好
下面的图来自《收获，不止SQL优化》一书：