利用oracle sql tuning advisor 进行sql调优

sql tunning advisor 使用的主要步骤:

1 建立tunning task

2 执行task

3 显示tunning 结果

4 根据建议来运行相应的调优方法

下面来按照这个顺序来实施一遍:

1 建立测试表以及索引

SQL> CREATE TABLE test_sql_advisor AS SELECT OWNER,OBJECT_NAME,OBJECT_ID FROM DBA_OBJECTS;

Table created

SQL> select count(*) from test_sql_advisor;

COUNT(*)
----------
757229
CREATE INDEX TEST_SQL_ADVISOR_idx ON TEST_SQL_ADVISOR(Object_Id);

2 授权

SYSDBA权限登录

SQL> GRANT ADVISOR TO noap;

Grant succeeded
SQL> GRANT SELECT_CATALOG_ROLE TO noap;

Grant succeeded
SQL> GRANT EXECUTE ON DBMS_SQLTUNE TO noap;

Grant succeeded

3 CREATE TASK

You can create tuning tasks from the following:
- SQL statement selected by SQL identifier from the cursor cache
- SQL Tuning Set containing multiple statements
- Text of a single SQL statement
- SQL statement selected by SQL identifier from the Automatic Workload Repository.

上面翻译可以理解为建立调优任务可以通过以下几种方式:
1 通过取得来自cursor cache 的sql_id来指定sql语句来建立任务
2 sql调优的集合包括的多个语句来建立任务
3 单一sql语句的文本来建立任务
4 通过用awr中相应的sql_id来取得sql语句建立任务
建立任务主要用的是DBMS_SQLTUNE.CREATE_TUNING_TASK 这个函数，该函数存在重写，下面的贴出来接口

1 基于SQL文本建立任务

-------------------- create_tuning_task - sql text format ------------------

-- NAME:

--     create_tuning_task - CRATE a TUNING TASK in order to tune a single SQL

--     statement (sql text format)

--

-- DESCRIPTION

--     This function is called to prepare the tuning of a single statement

--     given its text.

--     The function mainly creates an advisor task and sets its parameters.

--

-- PARAMETERS:

--     sql_text    (IN) - text of a SQL statement

--     bind_list   (IN) - a set of bind values

--     user_name   (IN) - the username for who the statement will be tuned

--     scope       (IN) - tuning scope (limited/comprehensive)

--     time_limit  (IN) - maximum duration in second for the tuning session

--     task_name   (IN) - optional tuning task name

--     description (IN) - maximum of 256 SQL tuning session description

--

-- RETURNS:

--     SQL tuning task unique name

--

-- EXCEPTIONS:

--     To be done

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

FUNCTION create_tuning_task(

sql_text    IN CLOB,

bind_list   IN sql_binds := NULL,

user_name   IN VARCHAR2  := NULL,

scope       IN VARCHAR2  := SCOPE_COMPREHENSIVE,

time_limit  IN NUMBER    := TIME_LIMIT_DEFAULT,

task_name   IN VARCHAR2  := NULL,

description IN VARCHAR2  := NULL)

RETURN VARCHAR2;

2 基于sql_id建立任务

--------------------- create_tuning_task - sql_id format --------------------

-- NAME:

--     create_tuning_task - sql_id format

--

-- DESCRIPTION

--     This function is called to prepare the tuning of a single statement

--     from the Cursor Cache given its identifier.

--     The function mainly creates an advisor task and sets its parameters.

--

-- PARAMETERS:

--     sql_id          (IN) - identifier of the statement

--     plan_hash_value (IN) - hash value of the sql execution plan

--     scope           (IN) - tuning scope (limited/comprehensive)

--     time_limit      (IN) - maximum tuning duration in second

--     task_name       (IN) - optional tuning task name

--     description     (IN) - maximum of 256 SQL tuning session description

--

-- RETURNS:

--     SQL tuning task unique name

--

-- EXCEPTIONS:

--     To be done

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

FUNCTION create_tuning_task(

sql_id          IN VARCHAR2,

plan_hash_value IN NUMBER   := NULL,

scope           IN VARCHAR2 := SCOPE_COMPREHENSIVE,

time_limit      IN NUMBER   := TIME_LIMIT_DEFAULT,

task_name       IN VARCHAR2 := NULL,

description     IN VARCHAR2 := NULL)

RETURN VARCHAR2;

3 基于AWR快照间隔以及相应SQL_ID建立任务

-------------- create_tuning_task - workload repository format --------------

-- NAME:

--     create_tuning_task - workload repository format

--

-- DESCRIPTION

--     This function is called to prepare the tuning of a single statement

--     from the workload repository given a range of snapshot identifiers.

--     The function mainly creates an advisor task and sets its parameters.

--

-- PARAMETERS:

--     begin_snap      (IN) - begin snapshot identifier

--     end_snap        (IN) - end snapshot identifier

--     sql_id          (IN) - identifier of the statement

--     plan_hash_value (IN) - plan hash value

--     scope           (IN) - tuning scope (limited/comprehensive)

--     time_limit      (IN) - maximum duration in second for tuning

--     task_name       (IN) - optional tuning task name

--     description     (IN) - maximum of 256 SQL tuning session description

--

-- RETURNS:

--     SQL tuning task unique name

--

-- EXCEPTIONS:

--     To be done

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

FUNCTION create_tuning_task(

begin_snap      IN NUMBER,

end_snap        IN NUMBER,

sql_id          IN VARCHAR2,

plan_hash_value IN NUMBER   := NULL,

scope           IN VARCHAR2 := SCOPE_COMPREHENSIVE,

time_limit      IN NUMBER   := TIME_LIMIT_DEFAULT,

task_name       IN VARCHAR2 := NULL,

description     IN VARCHAR2 := NULL)

RETURN VARCHAR2;

当然还有基于sqlset，以及SQL Performance Analyzer (SPA) task 建立任务的函数 这个以后再写专题吧
sample的建立是基于sql文本来做实验的，如下所示

DECLARE
MY_TASK_NAME VARCHAR2(30);
MY_SQLTEXT CLOB;
BEGIN
MY_SQLTEXT :='SELECT * FROM TEST_OBJECT_TTX WHERE OBJECT_ID = :BND';
MY_TASK_NAME := DBMS_SQLTUNE.CREATE_TUNING_TASK(SQL_TEXT => MY_SQLTEXT,
BIND_LIST=>SQL_BINDS(ANYDATA.CONVERTNUMBER(9)),
USER_NAME => 'NOAP',
SCOPE=>'COMPREHENSIVE',
TIME_LIMIT => 60,
TASK_NAME =>  'SQL_TUNING_TEST',
DESCRIPTION=>'TUNING TASK'
);

END;

建立后的状态为INITIAL 因为还没执行

SQL>  SELECT created,task_name,status FROM USER_ADVISOR_TASKS WHERE TASK_NAME='SQL_TUNING_TEST';

CREATED     TASK_NAME                      STATUS
----------- ------------------------------ -----------
2011-6-24 1 SQL_TUNING_TEST                INITIAL

4 EXECUTE TASK

SQL> BEGIN DBMS_SQLTUNE.EXECUTE_TUNING_TASK('SQL_TUNING_TEST'); END;
2  /

PL/SQL procedure successfully completed
SQL> SELECT status FROM USER_ADVISOR_TASKS WHERE task_name ='SQL_TUNING_TEST';

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

5 查询建议结果

SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK('SQL_TUNING_TEST') FROM DUAL;

该语句是一个CLOB字段的结果 点击自行查看 根据相应的建议优化sql

GENERAL INFORMATION SECTION
-------------------------------------------------------------------------------
Tuning Task Name   : SQL_TUNING_TEST
Tuning Task Owner  : NOAP
Workload Type      : Single SQL Statement
Scope              : COMPREHENSIVE
Time Limit(seconds): 60
Completion Status  : COMPLETED
Started at         : 06/24/2011 12:45:20
Completed at       : 06/24/2011 12:45:22
-------------------------------------------------------------------------------
Schema Name: NOAP
SQL ID     : 5k6fk8cynf60x
SQL Text   : SELECT * FROM TEST_SQL_ADVISOR WHERE OBJECT_ID = :BND
-------------------------------------------------------------------------------
FINDINGS SECTION (1 finding)
-------------------------------------------------------------------------------
1- Statistics Finding
---------------------
尚未分析表 "NOAP"."TEST_SQL_ADVISOR"。
Recommendation
--------------
- 考虑收集此表的优化程序统计信息。
execute dbms_stats.gather_table_stats(ownname => 'NOAP', tabname =>
'TEST_SQL_ADVISOR', estimate_percent =>
DBMS_STATS.AUTO_SAMPLE_SIZE, method_opt => 'FOR ALL COLUMNS SIZE
AUTO');
Rationale
---------
为了选择好的执行计划, 优化程序需要此表的最新统计信息。
-------------------------------------------------------------------------------
EXPLAIN PLANS SECTION
-------------------------------------------------------------------------------
1- Original
-----------
Plan hash value: 719217330
----------------------------------------------------------------------------------------------------
| Id  | Operation                   | Name                 | Rows  | Bytes | Cost (%CPU)| Time     |
----------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT            |                      |     1 |    96 |     2   (0)| 00:03:18 |
|   1 |  TABLE ACCESS BY INDEX ROWID| TEST_SQL_ADVISOR     |     1 |    96 |     2   (0)| 00:03:18 |
|*  2 |   INDEX RANGE SCAN          | TEST_SQL_ADVISOR_IDX |     1 |       |     1   (0)| 00:01:39 |
----------------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

2 - access("OBJECT_ID"=:BND)
-------------------------------------------------------------------------------

6 删除任务的方法

BEGIN dbms_sqltune.drop_tuning_task('SQL_TUNING_TEST'); END;

7 可以用到的视图

SELECT * FROM USER_ADVISOR_TASKS T WHERE TASK_NAME='SQL_TUNING_TEST';
SELECT * FROM DBA_SQLTUNE_STATISTICS
SELECT * FROM DBA_SQLTUNE_BINDS
SELECT * FROM DBA_SQLTUNE_PLANS WHERE TASK_ID=13009