Sql Tuning Advisor是10g以后出现的一个十分有用的调优工具，大多数情况下我们可以通过dbconsole或者Grid Control的web界面调用SQL Advisor；但如果系统中没有配置dbconsole或者Grid Control的话，我们则需要通过手动调用DBMS_SQLTUNE PL/SQL程序包来使用该特性。这里我列出一个针对单个SQL语句Autotune的脚本，具体脚本:

beginDBMS_SQLTUNE.drop_tuning_task('&task_name');
end;
/DECLAREmy_task_name VARCHAR2(30);my_sqltext CLOB;my_sqlid varchar2(30);
BEGINmy_sqlid := '&sqlid';my_task_name := dbms_sqltune.create_tuning_task(sql_id => my_sqlid,scope => 'COMPREHENSIVE',time_limit => 300,task_name => '&task_name',description => 'comment');
END;
/BEGINdbms_sqltune.execute_tuning_task(task_name => '&task_name');
END;
/SELECT status FROM USER_ADVISOR_TASKS WHERE task_name = '&task_name';SET LONG 10000
SET LONGCHUNKSIZE 10000
SET LINESIZE 100
set pages 60SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK('&task_name') FROM DUAL;

具体使用示例:

SQL> beginDBMS_SQLTUNE.drop_tuning_task('&task_name');
end;
/
Enter value for task_name: newtask
old   3:   DBMS_SQLTUNE.drop_tuning_task('&task_name');
new   3:   DBMS_SQLTUNE.drop_tuning_task('newtask');
begin
*
ERROR at line 1:
ORA-13605: The specified task or object newtask does not exist for the current
user.
ORA-06512: at "SYS.PRVT_ADVISOR", line 2307
ORA-06512: at "SYS.DBMS_ADVISOR", line 172
ORA-06512: at "SYS.DBMS_SQLTUNE", line 751
ORA-06512: at line 3SQL> DECLAREmy_task_name VARCHAR2(30);my_sqltext CLOB;my_sqlid varchar2(30);
BEGINmy_sqlid := '&sqlid';my_task_name := dbms_sqltune.create_tuning_task(sql_id => my_sqlid,scope => 'COMPREHENSIVE',time_limit => 300,task_name => '&task_name',description => 'comment');
END;
/
Enter value for sqlid: 17usubxchdf2w
old  11:   my_sqlid := '&sqlid';
new  11:   my_sqlid := '17usubxchdf2w';
Enter value for task_name: new_task
old  19:                           task_name => '&task_name',
new  19:                           task_name => 'new_task',SQL> BEGINdbms_sqltune.execute_tuning_task(task_name => '&task_name');
END;
/
Enter value for task_name: new_task
old   3:   dbms_sqltune.execute_tuning_task(task_name => '&task_name');
new   3:   dbms_sqltune.execute_tuning_task(task_name => 'new_task');PL/SQL procedure successfully completed.SQL> SELECT status FROM USER_ADVISOR_TASKS WHERE task_name = '&task_name';
Enter value for task_name: new_task
old   1: SELECT status FROM USER_ADVISOR_TASKS WHERE task_name = '&task_name'
new   1: SELECT status FROM USER_ADVISOR_TASKS WHERE task_name = 'new_task'STATUS
-----------
COMPLETEDSQL> SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK('&task_name') FROM DUAL;
Enter value for task_name: new_task
old   1: SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK('&task_name') FROM DUAL
new   1: SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK('new_task') FROM DUALDBMS_SQLTUNE.REPORT_TUNING_TASK('NEW_TASK')
----------------------------------------------------------------------------------------------------
GENERAL INFORMATION SECTION
-------------------------------------------------------------------------------
Tuning Task Name   : new_task
Tuning Task Owner  : SYS
Workload Type      : Single SQL Statement
Scope          : COMPREHENSIVE
Time Limit(seconds): 300
Completion Status  : COMPLETED
Started at     : 03/25/2011 00:14:41
Completed at       : 03/25/2011 00:14:45-------------------------------------------------------------------------------
Schema Name: SYS
SQL ID     : 17usubxchdf2w
SQL Text   : select count(t1) from hashtab-------------------------------------------------------------------------------
FINDINGS SECTION (1 finding)
-------------------------------------------------------------------------------1- Statistics Finding
---------------------Table "SYS"."HASHTAB" was not analyzed.Recommendation--------------- Consider collecting optimizer statistics for this table.execute dbms_stats.gather_table_stats(ownname => 'SYS', tabname =>'HASHTAB', estimate_percent => DBMS_STATS.AUTO_SAMPLE_SIZE,method_opt => 'FOR ALL COLUMNS SIZE AUTO');Rationale---------The optimizer requires up-to-date statistics for the table in order toselect a good execution plan.-------------------------------------------------------------------------------
EXPLAIN PLANS SECTION
-------------------------------------------------------------------------------1- Original
-----------
Plan hash value: 485915006------------------------------------------------------------------------------
| Id  | Operation      | Name    | Rows  | Bytes | Cost (%CPU)| Time     |
------------------------------------------------------------------------------
|   0 | SELECT STATEMENT   |         |     1 |    13 |     2   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE    |         |     1 |    13 |        |      |
|   2 |   TABLE ACCESS FULL| HASHTAB |   102 |  1326 |     2   (0)| 00:00:01 |
------------------------------------------------------------------------------