SQL优化篇--SQL TUNNING ADVICER使用
–STA调优（SQL文本）
DECLARE
my_task_name VARCHAR2(30);
my_sqltext CLOB;
BEGIN
my_sqltext := ‘select * from CUST_OB where object_name=’‘I_CDEF2’’’;
my_task_name := DBMS_SQLTUNE.CREATE_TUNING_TASK(
sql_text => my_sqltext,
user_name => ‘CRM’,
scope => ‘COMPREHENSIVE’,
time_limit => 60,
task_name => ‘tuning_sql_test1’,
description => ‘Task to tune a query on a specified table’);
DBMS_SQLTUNE.EXECUTE_TUNING_TASK( task_name => ‘tuning_sql_test1’);
END;
/
–STA调优（sqlid）
DECLARE
my_task_name VARCHAR2(30);
BEGIN
my_task_name := DBMS_SQLTUNE.CREATE_TUNING_TASK(
sql_id => ‘18k3qg9cr050h’,
scope => ‘COMPREHENSIVE’,
time_limit => 60,
task_name => ‘tuning_sql_test2’,
description => ‘Task to tune a query on a specified table’);
DBMS_SQLTUNE.EXECUTE_TUNING_TASK( task_name => ‘tuning_sql_test2’);
END;
/
–查看生成的STA报告
SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK( ‘tuning_sql_test1’) from DUAL;
–删除STA任务
begin
DBMS_SQLTUNE.DROP_TUNING_TASK(‘tuning_sql_test1’);
end;
一、创建测试数据
登陆fst用户
create table obj as select * from dba_objects;
exec dbms_stats.gather_table_stats(ownname=>‘FST’,tabname=>‘OB’,estimate_percent=>100,no_invalidate=>False,Cascade=>True);
二、使用STA调优SQL语句
1、根据sql语句调优
–1.1 创建优化任务并执行
DECLARE
my_task_name VARCHAR2(30);
my_sqltext CLOB;
BEGIN
my_sqltext := ‘select * from obj where object_id=101’;
my_task_name := DBMS_SQLTUNE.CREATE_TUNING_TASK(
sql_text => my_sqltext,
user_name => ‘FST’,
scope => ‘COMPREHENSIVE’,
time_limit => 60,
task_name => ‘tuning_sql_test1’,
description => ‘Task to tune a query on a specified table’);
DBMS_SQLTUNE.EXECUTE_TUNING_TASK( task_name => ‘tuning_sql_test1’);
END;
/
–1.2 查看优化任务是否完成，并查看优化结果
select task_name, status from USER_ADVISOR_LOG where task_name=‘tuning_sql_test1’;
SELECT sofar, totalwork FROM V$ADVISOR_PROGRESS;
SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK( ‘tuning_sql_test1’) from DUAL;
GENERAL INFORMATION SECTION
-------------------------------------------------------------------------------
Tuning Task Name : tuning_sql_test1
Tuning Task Owner : FST
Workload Type : Single SQL Statement
Scope : COMPREHENSIVE
Time Limit(seconds): 60
Completion Status : COMPLETED
Started at : 10/24/2018 10:47:24
Completed at : 10/24/2018 10:47:25
-------------------------------------------------------------------------------
Schema Name: FST
SQL ID : 1rk75xx3gns81
SQL Text : select * from obj where object_id=101
-------------------------------------------------------------------------------
FINDINGS SECTION (1 finding)
-------------------------------------------------------------------------------
1- Index Finding (see explain plans section below)
--------------------------------------------------
The execution plan of this statement can be improved by creating one or more
indices.
Recommendation (estimated benefit: 99.42%)
------------------------------------------
- Consider running the Access Advisor to improve the physical schema design
or creating the recommended index.
create index FST.IDX$$_0BF90001 on FST.OBJ("OBJECT_ID");
Rationale
---------
Creating the recommended indices significantly improves the execution plan
of this statement. However, it might be preferable to run "Access Advisor"
using a representative SQL workload as opposed to a single statement. This
will allow to get comprehensive index recommendations which takes into
account index maintenance overhead and additional space consumption.
-------------------------------------------------------------------------------
EXPLAIN PLANS SECTION
-------------------------------------------------------------------------------
1- Original
-----------
Plan hash value: 730912574
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 98 | 347 (1)| 00:00:05 |
|* 1 | TABLE ACCESS FULL| OBJ | 1 | 98 | 347 (1)| 00:00:05 |
--------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("OBJECT_ID"=101)
2- Using New Indices
--------------------
Plan hash value: 3281391003
----------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
----------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 98 | 2 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID| OBJ | 1 | 98 | 2 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IDX$$_0BF90001 | 1 | | 1 (0)| 00:00:01 |
----------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("OBJECT_ID"=101)
-------------------------------------------------------------------------------
–1.3删除优化任务
begin DBMS_SQLTUNE.DROP_TUNING_TASK(‘tuning_sql_test1’); end;
2、根据sql_id调优
多次执行下面的SQL
select * from obj where object_name = ‘I_CDEF2’;
–根据sql文本查询sql_id:
select sql_text,sql_id from v$sqlarea where sql_text like ‘%select *
from obj where object_name%’; 18k3qg9cr050h
–2.1 创建优化任务并执行
DECLARE my_task_name VARCHAR2(30); BEGIN my_task_name :=
DBMS_SQLTUNE.CREATE_TUNING_TASK(
sql_id => ‘18k3qg9cr050h’,
scope => ‘COMPREHENSIVE’,
time_limit => 60,
task_name => ‘tuning_sql_test2’,
description => ‘Task to tune a query on a specified table’); DBMS_SQLTUNE.EXECUTE_TUNING_TASK( task_name => ‘tuning_sql_test2’);
END; /
–2.2 查看优化任务是否完成，并查看优化结果
select task_name, status from USER_ADVISOR_LOG where
task_name=‘tuning_sql_test2’;
SELECT sofar, totalwork FROM V$ADVISOR_PROGRESS;
SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK( ‘tuning_sql_test2’) from DUAL;
GENERAL INFORMATION SECTION
-------------------------------------------------------------------------------
Tuning Task Name : tuning_sql_test2
Tuning Task Owner : FST
Workload Type : Single SQL Statement
Scope : COMPREHENSIVE
Time Limit(seconds): 60
Completion Status : COMPLETED
Started at : 10/24/2018 11:03:06
Completed at : 10/24/2018 11:03:07
-------------------------------------------------------------------------------
Schema Name: FST
SQL ID : 18k3qg9cr050h
SQL Text : select * from obj where object_name = 'I_CDEF2'
-------------------------------------------------------------------------------
FINDINGS SECTION (1 finding)
-------------------------------------------------------------------------------
1- Index Finding (see explain plans section below)
--------------------------------------------------
The execution plan of this statement can be improved by creating one or more
indices.
Recommendation (estimated benefit: 98.84%)
------------------------------------------
- Consider running the Access Advisor to improve the physical schema design
or creating the recommended index.
create index FST.IDX$$_0BFB0001 on FST.OBJ("OBJECT_NAME");
Rationale
---------
Creating the recommended indices significantly improves the execution plan
of this statement. However, it might be preferable to run "Access Advisor"
using a representative SQL workload as opposed to a single statement. This
will allow to get comprehensive index recommendations which takes into
account index maintenance overhead and additional space consumption.
-------------------------------------------------------------------------------
EXPLAIN PLANS SECTION
-------------------------------------------------------------------------------
1- Original
-----------
Plan hash value: 730912574
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 2 | 196 | 347 (1)| 00:00:05 |
|* 1 | TABLE ACCESS FULL| OBJ | 2 | 196 | 347 (1)| 00:00:05 |
--------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("OBJECT_NAME"='I_CDEF2')
2- Using New Indices
--------------------
Plan hash value: 3570812727
----------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
----------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 2 | 196 | 4 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID| OBJ | 2 | 196 | 4 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IDX$$_0BFB0001 | 2 | | 3 (0)| 00:00:01 |
----------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("OBJECT_NAME"='I_CDEF2')
-------------------------------------------------------------------------------
–2.3 删除优化任务
begin DBMS_SQLTUNE.DROP_TUNING_TASK(‘tuning_sql_test2’); end; /
3、其他优化建议
–登陆fst用户
create table ob as select * from dba_objects; create index idx2 on
ob(object_id,object_name);
–对应sql语句select * from ob where ob.object_id = 10;会走索引idx2
SQL> set autotrace traceonly SQL> select * from ob where ob.object_id
= 10;
Execution Plan
----------------------------------------------------------
Plan hash value: 2091480331
------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 207 | 3 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID| OB | 1 | 207 | 3 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IDX2 | 1 | | 2 (0)| 00:00:01 |
------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("OB"."OBJECT_ID"=10)
Note
-----
- dynamic sampling used for this statement (level=2)
Statistics
----------------------------------------------------------
7 recursive calls
0 db block gets
89 consistent gets
0 physical reads
0 redo size
1612 bytes sent via SQL*Net to client
519 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
–使用hint使sql语句走全部扫描（错误的执行计划）
SQL> select /*+ full(ob) */ * from ob where ob.object_id = 10;
Execution Plan
----------------------------------------------------------
Plan hash value: 1611727973
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 207 | 347 (1)| 00:00:05 |
|* 1 | TABLE ACCESS FULL| OB | 1 | 207 | 347 (1)| 00:00:05 |
--------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("OB"."OBJECT_ID"=10)
Note
-----
- dynamic sampling used for this statement (level=2)
Statistics
----------------------------------------------------------
10 recursive calls
0 db block gets
1334 consistent gets
881 physical reads
0 redo size
1609 bytes sent via SQL*Net to client
519 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
–下面使用STA调优select /*+ full(ob) */ * from ob where ob.object_id = 10语句
–创建优化任务并执行
declare l_task_name varchar2(30); l_sql clob; begin l_sql
:= ‘select /*+ full(ob) */ * from ob where ob.object_id = 10’;
l_task_name := DBMS_SQLTUNE.CREATE_TUNING_TASK(sql_text => l_sql,
user_name => ‘FST’,
scope => ‘COMPREHENSIVE’,
time_limit => 60,
task_name => ‘test01’,
description => null); end; /
–查看任务
select task_name,EXECUTION_START,EXECUTION_END,STATUS from
DBA_ADVISOR_LOG where task_name like ‘test%’;
–执行优化任务
BEGIN DBMS_SQLTUNE.EXECUTE_TUNING_TASK( task_name => ‘test01’ );
END; /
–查看调优建议结果
SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK(‘test01’) FROM DUAL;
GENERAL INFORMATION SECTION
-------------------------------------------------------------------------------
Tuning Task Name : test01
Tuning Task Owner : FST
Workload Type : Single SQL Statement
Scope : COMPREHENSIVE
Time Limit(seconds): 60
Completion Status : COMPLETED
Started at : 10/24/2018 09:39:40
Completed at : 10/24/2018 09:39:43
-------------------------------------------------------------------------------
Schema Name: FST
SQL ID : adh32wcz7bz1y
SQL Text : select /*+ full(ob) */ * from ob where ob.object_id = 10
-------------------------------------------------------------------------------
FINDINGS SECTION (2 findings)
-------------------------------------------------------------------------------
1- Statistics Finding --第一个调优建议：收集统计信息
---------------------
Table "FST"."OB" was not analyzed.
Recommendation
--------------
- Consider collecting optimizer statistics for this table.
execute dbms_stats.gather_table_stats(ownname => 'FST', tabname => 'OB',
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 to
select a good execution plan.
2- SQL Profile Finding (see explain plans section below) --第二个调优建议：使用profile绑定执行计划
--------------------------------------------------------
A potentially better execution plan was found for this statement.
Recommendation (estimated benefit: 99.75%)
------------------------------------------
- Consider accepting the recommended SQL profile.
execute dbms_sqltune.accept_sql_profile(task_name => 'test01', task_owner
=> 'FST', replace => TRUE);
Validation results
------------------
The SQL profile was tested by executing both its plan and the original plan
and measuring their respective execution statistics. A plan may have been
only partially executed if the other could be run to completion in less time.
Original Plan With SQL Profile % Improved
------------- ---------------- ----------
Completion Status: COMPLETE COMPLETE
Elapsed Time (s): .003867 .000014 99.63 %
CPU Time (s): .002799 0 100 %
User I/O Time (s): 0 0
Buffer Gets: 1247 3 99.75 %
Physical Read Requests: 0 0
Physical Write Requests: 0 0
Physical Read Bytes: 0 0
Physical Write Bytes: 0 0
Rows Processed: 1 1
Fetches: 1 1
Executions: 1 1
Notes
-----
1. Statistics for the original plan were averaged over 10 executions.
2. Statistics for the SQL profile plan were averaged over 10 executions.
-------------------------------------------------------------------------------
EXPLAIN PLANS SECTION
-------------------------------------------------------------------------------
1- Original With Adjusted Cost
------------------------------
Plan hash value: 1611727973
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 2 | 206 | 347 (1)| 00:00:05 |
|* 1 | TABLE ACCESS FULL| OB | 2 | 206 | 347 (1)| 00:00:05 |
--------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("OB"."OBJECT_ID"=10)
2- Using SQL Profile
--------------------
Plan hash value: 2091480331
------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 2 | 206 | 3 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID| OB | 2 | 206 | 3 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IDX2 | 2 | | 2 (0)| 00:00:01 |
------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("OB"."OBJECT_ID"=10)
-------------------------------------------------------------------------------
–这里我们使用第二个调优建议（创建sql profile）
SQL> execute dbms_sqltune.accept_sql_profile(task_name => ‘test01’,
task_owner => ‘FST’, replace => TRUE); PL/SQL procedure successfully
completed
–再次查看 select /*+ full(ob) */ * from ob where ob.object_id = 10语句执行计划
SQL> select /*+ full(ob) */ * from ob where ob.object_id = 10;
Execution Plan
----------------------------------------------------------
Plan hash value: 2091480331
------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 2 | 206 | 3 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID| OB | 2 | 206 | 3 (0)| 00:00:01 |
|* 2 | INDEX RANGE SCAN | IDX2 | 2 | | 2 (0)| 00:00:01 |
------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("OB"."OBJECT_ID"=10)
Note
-----
- SQL profile "SYS_SQLPROF_0166a41fe5e00001" used for this statement --使用了sql profile
Statistics
----------------------------------------------------------
10 recursive calls
0 db block gets
10 consistent gets
1 physical reads
0 redo size
1612 bytes sent via SQL*Net to client
519 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed