dbms_sqltune包的使用

DBMS_SQLTUNE优化SQL 是在oracle10g才出来的新特性，使用它能很大程度上方便对sql的分析和优化。执行DBMS_SQLTUNE包进行sql优化需要有advisor的权限：

stat>grant advisor to user;

Grant succeeded.

使用DBMS_SQLTUNE包进行SQL优化，大致可以分为四个步骤：

创建优化任务
执行优化任务
显示优化任务的结果
按照建议执行优化

create table scott.t2 as select * from dba_objects;


declare
    tuning_task_name varchar2(30);
    tuning_sqltext clob;
begin
   tuning_sqltext:='select count(*) from t2 where upper(owner)=:owner';
   tuning_task_name:=dbms_sqltune.create_tuning_task(
       sql_text     =>tuning_sqltext,
       bind_list    =>sql_binds(anydata.convertvarchar2(100)),
       user_name    =>'SCOTT',
       scope        =>'COMPREHENSIVE',
       time_limit   =>60,
       task_name    =>'first_tuning_task13',
       description  =>'tune t2 count');
end;
/

dbms_sqltune.drop_tuning_task('first_tuning_task13');

PROCEDURE DROP_TUNING_TASK
 Argument Name                  Type                    In/Out Default?
 ------------------------------ ----------------------- ------ --------
 TASK_NAME                      VARCHAR2                IN
 
SQL> select task_name from user_advisor_log;

TASK_NAME
------------------------------
first_tuning_task13

SQL> exec dbms_sqltune.execute_tuning_task('first_tuning_task13');

PL/SQL procedure successfully completed.

SQL> select status from user_advisor_tasks where task_name='first_tuning_task13';

STATUS
-----------
COMPLETED

SQL> set long 8000
SQL> select dbms_sqltune.report_tuning_task('first_tuning_task13') from dual;

...

  Recommendation (estimated benefit: 100%)
  ----------------------------------------
  - Consider running the Access Advisor to improve the physical sche
ma design
    or creating the recommended index.
    create index SCOTT.IDX$$_00780001 on SCOTT.T2(UPPER
('OWNER'));

...
 
 
 create index SCOTT.IDX$$_00780001 on SCOTT.T2(UPPER(OWNER));