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
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
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
