使用 sql profile 绑定执行计划
Posted by wukaiqiang; tagged with none
SQLT工具包含一个脚本，名字是 coe_load_sql_profile.sql,下面以用户SCOTT的EMP表为例，说明如何使用该脚本固定sql profile.
1.
SQL> -- 对emp的列ename创建一个索引
SQL> create index i_emp_ename on scott.emp(ename);
SQL> --收集统计信息
SQL> exec dbms_stats.gather_table_stats(ownname=>'SCOTT',tabname=>'EMP')
SQL> -- 对emp的列ename创建一个索引
SQL> create index i_emp_ename on scott.emp(ename);
SQL> --收集统计信息
SQL> exec dbms_stats.gather_table_stats(ownname=>'SCOTT',tabname=>'EMP')
2.运行原始的SQL语句
SQL> select ename from scott.emp where ename='MILLER';
ENAME
----------
MILLER
执行计划如下:
-------------------------------
SQL_ID 329d885bxvrcr
-------------------------------
Plan hash value: 4001599462
-------------------------------------------------
| Id | Operation | Name | E-Rows |
-------------------------------------------------
| 0 | SELECT STATEMENT | | |
|* 1 | INDEX RANGE SCAN| I_EMP_ENAME | 1 |
-------------------------------------------------
SQL> select ename from scott.emp where ename='MILLER';
ENAME
----------
MILLER
执行计划如下:
-------------------------------
SQL_ID 329d885bxvrcr
-------------------------------
Plan hash value: 4001599462
-------------------------------------------------
| Id | Operation | Name | E-Rows |
-------------------------------------------------
| 0 | SELECT STATEMENT | | |
|* 1 | INDEX RANGE SCAN| I_EMP_ENAME | 1 |
-------------------------------------------------
--这是我们需要更改的plan
运行带有hint的SQL
SQL> select /+ FULL (EMP) / ename from scott.emp where ename='MILLER';
执行计划如下:
-------------------------------
SQL_ID 4f74t4ab7rd5y
-------------------------------
Plan hash value: 3956160932
-------------------------------------------
| Id | Operation | Name | E-Rows |
-------------------------------------------
| 0 | SELECT STATEMENT | | |
|* 1 | TABLE ACCESS FULL| EMP | 1 |
-------------------------------------------
SQL> select /*+ FULL (EMP) */ ename from scott.emp where ename='MILLER';
执行计划如下:
-------------------------------
SQL_ID 4f74t4ab7rd5y
-------------------------------
Plan hash value: 3956160932
-------------------------------------------
| Id | Operation | Name | E-Rows |
-------------------------------------------
| 0 | SELECT STATEMENT | | |
|* 1 | TABLE ACCESS FULL| EMP | 1 |
-------------------------------------------
--这是我们需要的plan
4: 可以通过下面的SQL获取这2个SQL的sql_id和plan_hash_value
SQL> select sql_id ,plan_hash_value, sql_text from v$sql where sql_text like '%scott.emp%';
SQL_ID PLAN_HASH_VALUE SQL_TEXT
------------- --------------- ----------------------------------------------------------------------------------------
4f74t4ab7rd5y 3956160932 select /*+ FULL (EMP) */ ename from scott.emp where ename='MILLER'
329d885bxvrcr 4001599462 select ename from scott.emp where ename='MILLER'
SQL> select sql_id ,plan_hash_value, sql_text from v$sql where sql_text like '%scott.emp%';
SQL_ID PLAN_HASH_VALUE SQL_TEXT
------------- --------------- ----------------------------------------------------------------------------------------
4f74t4ab7rd5y 3956160932 select /*+ FULL (EMP) */ ename from scott.emp where ename='MILLER'
329d885bxvrcr 4001599462 select ename from scott.emp where ename='MILLER'
--329d885bxvrcr - 这是原始语句的SQL ID
--4f74t4ab7rd5y - 这是使用hint的SQL ID
--3956160932 - 这是需要替换的plan hash value.
5.进行plan的替换
--这两个计划都需要在缓存或AWR中
--需要以具有DBA权限的用户身份连接，例如SYSTEM
SQL> conn system
SQL> @coe_load_sql_profile.sql
Parameter 1:
ORIGINAL_SQL_ID (required)
输入 1 的值: 329d885bxvrcr
Parameter 2:
MODIFIED_SQL_ID (required)
输入 2 的值: 4f74t4ab7rd5y
Parameter 3:
PLAN_HASH_VALUE (required)
输入 3 的值: 3956160932
Values passed to coe_load_sql_profile:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ORIGINAL_SQL_ID: "329d885bxvrcr"
MODIFIED_SQL_ID: "4f74t4ab7rd5y"
PLAN_HASH_VALUE: "3956160932"
ORIGINAL:329D885BXVRCR MODIFIED:4F74T4AB7RD5Y PHV:3956160932 SIGNATURE:15822026218863957422 CREATED BY COE_LOAD_SQL_PROFILE.SQL
SQL>SET ECHO OFF;
****************************************************************************
* Enter SYSTEM password to export staging table STGTAB_SQLPROF_329d885bxvrcr
****************************************************************************
Export: Release 11.2.0.4.0 - Production on 星期二 12月 5 15:36:24 2017
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
口令:
coe_load_sql_profile completed.
SQL>
SQL> conn system
SQL> @coe_load_sql_profile.sql
Parameter 1:
ORIGINAL_SQL_ID (required)
输入 1 的值: 329d885bxvrcr
Parameter 2:
MODIFIED_SQL_ID (required)
输入 2 的值: 4f74t4ab7rd5y
Parameter 3:
PLAN_HASH_VALUE (required)
输入 3 的值: 3956160932
Values passed to coe_load_sql_profile:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ORIGINAL_SQL_ID: "329d885bxvrcr"
MODIFIED_SQL_ID: "4f74t4ab7rd5y"
PLAN_HASH_VALUE: "3956160932"
ORIGINAL:329D885BXVRCR MODIFIED:4F74T4AB7RD5Y PHV:3956160932 SIGNATURE:15822026218863957422 CREATED BY COE_LOAD_SQL_PROFILE.SQL
SQL>SET ECHO OFF;
****************************************************************************
* Enter SYSTEM password to export staging table STGTAB_SQLPROF_329d885bxvrcr
****************************************************************************
Export: Release 11.2.0.4.0 - Production on 星期二 12月 5 15:36:24 2017
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
口令:
coe_load_sql_profile completed.
SQL>
6.运行原来的SQL语句
SQL>conn scott/tiger
SQL> select ename from scott.emp where ename='MILLER';
PLAN_TABLE_OUTPUT
-------------------------------
SQL_ID 329d885bxvrcr
-------------------------------
Plan hash value: 3956160932
-------------------------------------------
| Id | Operation | Name | E-Rows |
-------------------------------------------
| 0 | SELECT STATEMENT | | |
|* 1 | TABLE ACCESS FULL| EMP | 1 |
-------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("ENAME"='MILLER')
Note
-----
- SQL profile 329D885BXVRCR_3956160932 used for this statement
SQL>conn scott/tiger
SQL> set autot traceonly explain stat
SQL> select ename from scott.emp where ename='MILLER';
查看是否生效：
PLAN_TABLE_OUTPUT
-------------------------------
SQL_ID 329d885bxvrcr
-------------------------------
Plan hash value: 3956160932
-------------------------------------------
| Id | Operation | Name | E-Rows |
-------------------------------------------
| 0 | SELECT STATEMENT | | |
|* 1 | TABLE ACCESS FULL| EMP | 1 |
-------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("ENAME"='MILLER')
Note
-----
- SQL profile 329D885BXVRCR_3956160932 used for this statement
我们可以看到，原始的SQL现在和使用hint的sql具有相同的plan_hash_value和plan。
此外，我们看到这个SQL启用了一个SQL配置文件。
查看系统中有哪些绑定的执行计划：
–查看绑定的sql profile
select * from dba_sql_profiles;
–删除上面绑定执行计划
begin
DBMS_SQLTUNE.DROP_SQL_PROFILE(name => ‘coe_1g1k2rcasn516_3203434082’);
end;
/
注意：绑定计划不能用sys用户。