.Oracle固定执行计划之SQL PROFILE概要文件

1.  引子
Oracle系统为了合理分配和使用系统的资源提出了概要文件的概念。所谓概要文件，就是一份描述如何使用系统的资源(主要是CPU资源)的配置文件。将概要文件赋予某个数据库用户，在用户连接并访问数据库服务器时，系统就按照概要文件给他分配资源。

包括:

1、管理数据库系统资源。
利用Profile来分配资源限额，必须把初始化参数resource_limit设置为true默认是TRUE的。
2、管理数据库口令及验证方式。
默认给用户分配的是DEFAULT概要文件，将该文件赋予了每个创建的用户。但该文件对资源没有任何限制，因此管理员常常需要根据自己数据库系统的环境自行建立概要文件。

2.  概要文件限制
概要文件主要可以对数据库系统如下指标进行限制。

1）用户的最大并发会话数（SESSION_PER_USER)

2）每个会话的CPU时钟限制（CPU_PER_SESSION）

3）每次调用的CPU时钟限制，调用包含解析、执行命令和获取数据等等。（CPU_PER_CALL）

4）最长连接时间。一个会话的连接时间超过指定时间之后，Oracle会自动的断开连接（CONNECT_TIME）

5）最长空闲时间。如果一个会话处于空闲状态超过指定时间，Oracle会自动断开连接（IDLE_TIME）

6）每个会话可以读取的最大数据块数量（LOGICAL_READS_PER_SESSION）

7）每次调用可以读取的最大数据块数量（LOGICAL_READS_PER_CALL）

8）SGA私有区域的最大容量（PRIVATE_SGA）

概要文件对口令的定义和限制如下：

1）登录失败的最大尝试次数（FAILED_LOGIN_ATTEMPTS）

2）口令的最长有效期(PASSWORD_LIFE_TIME)

3）口令在可以重用之前必须修改的次数(PASSWORD_REUSE_MAX)

4）口令在可以重用之前必须经过的天数(PASSWORD_REUSE_TIME)

5）超过登录失败的最大允许尝试次数后，账户被锁定的天数

6）指定用于判断口令复杂度的函数名

在指定概要文件之后，DBA可以手工的将概要文件赋予每个用户。但是概要文件不是立即生效，而是要将初始化参数文件中的参数RESOURCE_LIMIT设置为TRUE之后，概要文件才会生效。

3.  SQL PROFILE
SQL PROFILE在ORACLE10g中引入，主要目的侧重于SQL优化，弥补了存储概要的缺点.

DBA可以使用SQL调整顾问(STA)或SQL访问顾问(SAA)来识别可以得到更好性能的SQL语句，

这些语句可以保存在SQL调整集、一个AWR快照或保存在当前的库缓存中，一旦识别出调整候选者， 这些顾问程序就开始分析捕获到的语句以期获得更好的性能，然后生成专用的语句扩展(就叫做SQL配置文件)并重写SQL语句以在执行期间获取更佳的性能。

与存储概要类似，一个SQL配置文件提供了使用更好的执行计划的能力(如果这个执行计

划是可用的)，SQL配置文件也可以象存储概要一样分阶段执行，或限制到对特定会话才能执行该SQL配置文件，但是大多数重要的改进超过了存储概要.

SQLProfile对于一下类型语句有效：

SELECT语句；

UPDATE语句；

INSERT语句（仅当使用SELECT子句时有效）；

DELETE语句；

CREATE语句（仅当使用SELECT子句时有效）；

MERGE语句（仅当作UPDATE和INSERT操作时有效）。

另外，使用SQL Profile还必须有CREATE ANY SQL PROFILE、DROP ANY SQL PROFILE和ALTER ANY SQL PROFILE等系统权限。

4.  测试一
创建表

tpcc@TOADDB> create table t1 as selectobject_id,object_name from dba_objects where rownum<=50000;

Table created.

tpcc@TOADDB> create table t2 as select * fromdba_objects;

Table created.

创建索引：

tpcc@TOADDB> create index t2_idx on t2(object_id);

Index created.

收集统计信息：

tpcc@TOADDB> execdbms_stats.gather_table_stats(user,'t1',cascade=>true,method_opt=>'forall columns size 1');

PL/SQL procedure successfully completed.

tpcc@TOADDB> execdbms_stats.gather_table_stats(user,'t1',cascade=>true,method_opt=>'forall columns size 1');

PL/SQL procedure successfully completed.

执行无HINT的SQL
tpcc@TOADDB> set autotrace on

tpcc@TOADDB> select t1.*,t2.owner from t1,t2 wheret1.object_name like '%T1%' and t1.object_id=t2.object_id;

42 rows selected.

Execution Plan

----------------------------------------------------------

Plan hash value: 1838229974

---------------------------------------------------------------------------

| Id | Operation       | Name | Rows  | Bytes | Cost (%CPU)| Time          |

---------------------------------------------------------------------------

|   0| SELECT STATEMENT   |     |  2500 |    97K|  498   (1)| 00:00:01 |

|*  1|  HASH JOIN          |           |  2500 |    97K|  498   (1)| 00:00:01 |

|*  2|   TABLE ACCESS FULL| T1   | 2500 | 72500 |    68   (0)| 00:00:01 |

|   3|   TABLE ACCESS FULL| T2   | 92021 |  988K|   430   (1)| 00:00:01 |

---------------------------------------------------------------------------

Predicate Information (identified byoperation id):

---------------------------------------------------

1-access("T1"."OBJECT_ID"="T2"."OBJECT_ID")

2- filter("T1"."OBJECT_NAME" LIKE '%T1%' AND"T1"."OBJECT_NAME" IS

NOT NULL)

Statistics

----------------------------------------------------------

1 recursive calls

0  dbblock gets

1789 consistent gets

0 physical reads

0  redosize

2350  bytes sent via SQL*Net toclient

573  bytes received via SQL*Net from client

4 SQL*Net roundtrips to/from client

0 sorts (memory)

0 sorts (disk)

42  rowsprocessed

执行带Hint的SQL
SQL>select /*+ use_nl(t1 t2) index(t2)*/ t1.*,t2.owner from t1,t2 where t1.object_name like '%T1%' and t1.object_id=t2.object_id;

42 rows selected.

Execution Plan

----------------------------------------------------------

Plan hash value: 1022743391

---------------------------------------------------------------------------------------

| Id | Operation                  | Name  | Rows  | Bytes | Cost (%CPU)|Time     |

---------------------------------------------------------------------------------------

|   0| SELECT STATEMENT        |           | 2500 |    97K|  5069         (1)|00:00:01 |

|   1|  NESTED LOOPS                       |           |  2500|    97K| 5069         (1)| 00:00:01 |

|   2|   NESTED LOOPS                     |          |  2500 |    97K| 5069         (1)| 00:00:01 |

|*  3|    TABLE ACCESS FULL         | T1     |  2500 | 72500 |    68    (0)|00:00:01 |

|*  4|    INDEX RANGE SCAN         |T2_IDX |     1 |       |    1   (0)| 00:00:01 |

|   5|   TABLE ACCESS BY INDEX ROWID| T2     |    1 |    11 |     2       (0)|00:00:01 |

---------------------------------------------------------------------------------------

Predicate Information (identified byoperation id):

---------------------------------------------------

3- filter("T1"."OBJECT_NAME" LIKE '%T1%' AND"T1"."OBJECT_NAME" IS NOT

NULL)

4-access("T1"."OBJECT_ID"="T2"."OBJECT_ID")

Statistics

----------------------------------------------------------

1 recursive calls

0  dbblock gets

304  consistent gets

24 physical reads

0  redosize

2350  bytes sent via SQL*Net toclient

573  bytes received via SQL*Net from client

4 SQL*Net roundtrips to/from client

0 sorts (memory)

0 sorts (disk)

42  rowsprocessed

使用SQL PROFILE
查找执行SQL的SQL_ID

tpcc@TOADDB> select sql_id,sql_text from v$sqlwhere sql_text like '%t1.object_name%';

SQL_ID

-------------

SQL_TEXT

----------------------------------------------------------------------------------------------------

4zbqykx89yc8v

select t1.*,t2.owner from t1,t2 wheret1.object_name like '%T1%' and t1.object_id=t2.object_id

18bphz37dajq9

select /*+ use_nl(t1 t2) index(t2) */t1.*,t2.owner from t1,t2 where t1.object_name like '%T1%' and

t1.object_id=t2.object_id

运行存储过程如下：

var tuning_task varchar2(100);  
DECLARE  
  l_sql_id v$session.prev_sql_id%TYPE; 
   l_tuning_task VARCHAR2(30);  
 BEGIN  
   l_sql_id:='4zbqykx89yc8v';  
   l_tuning_task := dbms_sqltune.create_tuning_task(sql_id =>l_sql_id);  
   :tuning_task:=l_tuning_task;  
   dbms_sqltune.execute_tuning_task(l_tuning_task);  
   dbms_output.put_line(l_tuning_task);  
 END;
/

TASK_114

PL/SQL procedure successfully completed.

查看task的名字

tpcc@TOADDB> print tuning_task;

TUNING_TASK

----------------------------------------------------------------------------------------------------

TASK_114

查看执行报告

set long 99999

col comments format a200
SELECT dbms_sqltune.report_tuning_task(:tuning_task)COMMENTS FROM dual;

COMMENTS

----------------------------------------------------------------------------------------------------

GENERAL INFORMATION SECTION

-------------------------------------------------------------------------------

Tuning Task Name   : TASK_114

Tuning Task Owner  : TPCC

Workload Type    : Single SQL Statement

Scope                    : COMPREHENSIVE

Time Limit(seconds): 1800

Completion Status  : COMPLETED

Started at            : 03/06/2016 05:27:21

Completed at     : 03/06/2016 05:27:24

-------------------------------------------------------------------------------

Schema Name: TPCC

SQL ID         : 4zbqykx89yc8v

SQL Text  : select t1.*,t2.owner from t1,t2 where t1.object_name like '%T1%'

and t1.object_id=t2.object_id

-------------------------------------------------------------------------------

FINDINGS SECTION (1 finding)

-------------------------------------------------------------------------------

1- SQL Profile Finding (see explain planssection below)

--------------------------------------------------------

Apotentially better execution plan was found for this statement.

Recommendation (estimated benefit: 83.08%)

------------------------------------------

-Consider accepting the recommended SQL profile.

executedbms_sqltune.accept_sql_profile(task_name => 'TASK_114',

task_owner =>'TPCC', replace => TRUE);

Validation results

------------------

TheSQL profile was tested by executing both its plan and the original plan

andmeasuring their respective execution statistics. A plan may have been

only partially executed if the other could be run to completion in lesstime.

Original Plan  With SQL Profile  % Improved

-------------  ----------------  ----------

Completion Status:               COMPLETE        COMPLETE

Elapsed Time (s):          .012865   .004556     64.58 %

CPUTime (s):                 .0124     .0045        63.7%

User I/O Time (s):                        0                    0

Buffer Gets:                               1787                302       83.1%

Physical Read Requests:            0                    0

Physical Write Requests:           0                    0

Physical Read Bytes:                   0                    0

Physical Write Bytes:                0                    0

Rows Processed:               42                 42

Fetches:                               42                 42

Executions:                          1                    1

Notes

-----

1.Statistics for the original plan were averaged over 10 executions.

2.Statistics for the SQL profile plan were averaged over 10 executions.

-------------------------------------------------------------------------------

EXPLAIN PLANS SECTION

-------------------------------------------------------------------------------

1- Original With Adjusted Cost

------------------------------

Plan hash value: 1838229974

---------------------------------------------------------------------------

| Id | Operation       | Name | Rows  | Bytes | Cost (%CPU)| Time          |

---------------------------------------------------------------------------

|   0| SELECT STATEMENT   |     |    42 |  1680 |  498   (1)| 00:00:01 |

|*  1|  HASH JOIN          |           |    42 |  1680 |  498   (1)| 00:00:01 |

|*  2|   TABLE ACCESS FULL| T1   |   42 |  1218 |    68  (0)| 00:00:01 |

|   3|   TABLE ACCESS FULL| T2   | 92021 |  988K|   430   (1)| 00:00:01 |

---------------------------------------------------------------------------

Predicate Information (identified byoperation id):

---------------------------------------------------

1-access("T1"."OBJECT_ID"="T2"."OBJECT_ID")

2- filter("T1"."OBJECT_NAME" LIKE '%T1%' AND"T1"."OBJECT_NAME" IS

NOT NULL)

2- Using SQL Profile

--------------------

Plan hash value: 1022743391

---------------------------------------------------------------------------------------

| Id | Operation                  | Name  | Rows  | Bytes | Cost (%CPU)|Time     |

---------------------------------------------------------------------------------------

|   0| SELECT STATEMENT        |           |   42 |  1680 |   152 (0)|00:00:01 |

|   1|  NESTED LOOPS                       |          |    42 |  1680 |  152 (0)| 00:00:01 |

|   2|   NESTED LOOPS                     |          |    42 |  1680 |  152 (0)| 00:00:01 |

|*  3|    TABLE ACCESS FULL         | T1     |    42 | 1218 |    68   (0)| 00:00:01 |

|*  4|    INDEX RANGE SCAN         |T2_IDX |     1 |       |    1   (0)| 00:00:01 |

|   5|   TABLE ACCESS BY INDEX ROWID| T2     |    1 |    11 |     2       (0)|00:00:01 |

---------------------------------------------------------------------------------------

Predicate Information (identified byoperation id):

---------------------------------------------------

3- filter("T1"."OBJECT_NAME" LIKE '%T1%' AND"T1"."OBJECT_NAME" IS NOT

NULL)

4-access("T1"."OBJECT_ID"="T2"."OBJECT_ID")

-------------------------------------------------------------------------------

接受分析建议
报告中给出了执行方法，如上红色部分

接受报告的建议，验证一下如下：

tpcc@TOADDB> execute dbms_sqltune.accept_sql_profile(task_name=> 'TASK_114',task_owner => 'TPCC', replace => TRUE);

PL/SQL procedure successfully completed.

执行测试
再执行原先命令如下：

tpcc@TOADDB> select t1.*,t2.owner from t1,t2 wheret1.object_name like '%T1%' and t1.object_id=t2.object_id;

42 rows selected.

Execution Plan

----------------------------------------------------------

Plan hash value: 1022743391

---------------------------------------------------------------------------------------

| Id | Operation                  | Name  | Rows  | Bytes | Cost (%CPU)|Time     |

---------------------------------------------------------------------------------------

|   0| SELECT STATEMENT        |           |   42 |  1680 |   152 (0)|00:00:01 |

|   1|  NESTED LOOPS                       |           |    42|  1680 |   152 (0)|00:00:01 |

|   2|   NESTED LOOPS                     |          |    42 |  1680 |  152 (0)| 00:00:01 |

|*  3|    TABLE ACCESS FULL         | T1     |    42 | 1218 |    68   (0)| 00:00:01 |

|*  4|    INDEX RANGE SCAN         |T2_IDX |     1 |       |    1   (0)| 00:00:01 |

|   5|   TABLE ACCESS BY INDEX ROWID| T2     |    1 |    11 |     2       (0)|00:00:01 |

---------------------------------------------------------------------------------------

Predicate Information (identified byoperation id):

---------------------------------------------------

3- filter("T1"."OBJECT_NAME" LIKE '%T1%' AND"T1"."OBJECT_NAME" IS NOT

NULL)

4-access("T1"."OBJECT_ID"="T2"."OBJECT_ID")

Note

-----

- SQL profile"SYS_SQLPROF_01534b8309b90000" used for this statement

- this is an adaptive plan

Statistics

----------------------------------------------------------

35 recursive calls

0  dbblock gets

317  consistent gets

1 physical reads

0  redosize

2350  bytes sent via SQL*Net toclient

573  bytes received via SQL*Net from client

4 SQL*Net roundtrips to/from client

1 sorts (memory)

0 sorts (disk)

42  rowsprocessed

启用了PROFILE，PS：如果执行中多加几个空格，并不会影响PROFILE的生效的。

5.  维护操作
禁用命令
如下：

begin

dbms_sqltune.alter_sql_profile(

name            => 'SYS_SQLPROF_01534b8309b90000',

attribute_name  => 'status',

value           => 'disabled');

end;

/

启用命令
如下：

begin

dbms_sqltune.alter_sql_profile(

name            => 'SYS_SQLPROF_01534b8309b90000',

attribute_name  => 'status',

value           => 'enabled');

end;

/

查看使用的PROFILE
如下：

SQL>SELECT task_name,status FROMUSER_ADVISOR_TASKS ;

删除PROFILE
BEGIN

DBMS_SQLTUNE.DROP_SQL_PROFILE(name => 'SYS_SQLPROF_01534b8309b90000');

END;

/  
---------------------
作者：badman250
来源：CSDN
原文：https://blog.csdn.net/notbaron/article/details/50830910
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