oracle 11g 自己主动调整

--:自己主动调教计划

begin

  dbms_workload_repository.create_snapshot();

end;





select /*+ result_cache */ count(*) from (select * from  HJ.dbtan where object_type='TABLE' ORDER BY 1 DESC ,2 ASC ,3 DESC ,4 ASC);





begin

  dbms_workload_repository.create_snapshot();

end;





--ft8s1pfmz9ph0

SET SERVEROUTPUT ON

DECLARE

  l_sql_tune_task_id  VARCHAR2(100);

BEGIN

  l_sql_tune_task_id := DBMS_SQLTUNE.create_tuning_task (

                          begin_snap  => 21,

                          end_snap    => 22,

                          sql_id      => 'ft8s1pfmz9ph0',

                          scope       => DBMS_SQLTUNE.scope_comprehensive,

                          time_limit  => 300,

                          task_name   => 'ft8s1pfmz9ph0d_AWR_tuning_task',

                          description => 'Tuning task for statement f3hc7r4trnn1d in AWR.');

  DBMS_OUTPUT.put_line('l_sql_tune_task_id: ' || l_sql_tune_task_id);

END;





begin DBMS_SQLTUNE.execute_tuning_task(task_name => 'ft8s1pfmz9ph0d_AWR_tuning_task');end;

SELECT DBMS_SQLTUNE.report_tuning_task('ft8s1pfmz9ph0d_AWR_tuning_task') AS recommendations FROM dual;





GENERAL INFORMATION SECTION

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

Tuning Task Name   : ft8s1pfmz9ph0d_AWR_tuning_task

Tuning Task Owner  : SYS

Workload Type      : Single SQL Statement

Scope              : COMPREHENSIVE

Time Limit(seconds): 300

Completion Status  : COMPLETED

Started at         : 09/01/2014 14:55:32

Completed at       : 09/01/2014 14:55:44





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

Schema Name: SYS

SQL ID     : ft8s1pfmz9ph0

SQL Text   : select /*+ result_cache */ count(*) from (select * from 

             HJ.dbtan where object_type='TABLE' ORDER BY 1 DESC ,2 ASC ,3

             DESC ,4 ASC)





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

FINDINGS SECTION (2 findings)

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





1- Statistics Finding

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

  尚未分析表 "HJ"."DBTAN"。

Recommendation

  --------------

  - 考虑收集此表的优化程序统计信息。

execute dbms_stats.gather_table_stats(ownname => 'HJ', tabname =>

            'DBTAN', estimate_percent => DBMS_STATS.AUTO_SAMPLE_SIZE,

            method_opt => 'FOR ALL COLUMNS SIZE AUTO');

  Rationale

  ---------

    为了选择好的运行计划, 优化程序须要此表的最新统计信息。

2- Index Finding (see explain plans section below)

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

  通过创建一个或多个索引能够改进此语句的运行计划。

  Recommendation (estimated benefit: 95.98%)

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

  - 考虑执行能够改进物理方案设计的訪问指导或者创建推荐的索引。

    create index HJ.IDX$$_00360001 on HJ.DBTAN("OBJECT_TYPE");

  Rationale

  ---------

    创建推荐的索引能够显著地改进此语句的执行计划。

可是, 使用典型的 SQL 工作量执行 "訪问指导"

    可能比单个语句更可取。通过这样的方法能够获得全面的索引建议案, 包含计算索引维护的开销和附加的空间消耗。

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

EXPLAIN PLANS SECTION

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

1- Original

-----------

Plan hash value: 1782547706

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

| Id  | Operation           | Name                       | Rows  | Bytes | Cost (%CPU)| Time     |

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

|   0 | SELECT STATEMENT    |                            |     1 |    11 |  4706   (1)| 00:00:57 |

|   1 |  RESULT CACHE       | 81z3k6zbauk9s2c83c03s270ja |       |       |            |          |

|   2 |   SORT AGGREGATE    |                            |     1 |    11 |            |          |

|*  3 |    TABLE ACCESS FULL| DBTAN                      | 40006 |   429K|  4706   (1)| 00:00:57 |

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

Predicate Information (identified by operation id):

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

   3 - filter("OBJECT_TYPE"='TABLE')

Result Cache Information (identified by operation id):

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

   1 - column-count=1; dependencies=(HJ.DBTAN); attributes=(single-row); parameters=(nls); name="select /*+ result_cache */ count(*) from (select * from  HJ.dbtan where object_type='TABLE' ORDER BY 1 DESC ,2 ASC ,3 DESC ,4 AS

2- Using New Indices

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

Plan hash value: 2810514733

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

| Id  | Operation          | Name                       | Rows  | Bytes | Cost (%CPU)| Time     |

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

|   0 | SELECT STATEMENT   |                            |     1 |    11 |   189   (1)| 00:00:03 |

|   1 |  RESULT CACHE      | 27yjysxpdun18b2utun82bynny |       |       |            |          |

|   2 |   SORT AGGREGATE   |                            |     1 |    11 |            |          |

|*  3 |    INDEX RANGE SCAN| IDX$$_00360001             | 40006 |   429K|   189   (1)| 00:00:03 |

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

Predicate Information (identified by operation id):

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

   3 - access("OBJECT_TYPE"='TABLE')

Result Cache Information (identified by operation id):

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

   1 - column-count=1; dependencies=(HJ.DBTAN); attributes=(single-row, ordered); parameters=(nls); name="select /*+ result_cache */ count(*) from (select * from  HJ.dbtan where object_type='TABLE' ORDER BY 1 DESC ,2 ASC ,3 DESC ,4 AS"

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





begin DBMS_SQLTUNE.drop_tuning_task (task_name => 'ft8s1pfmz9ph0d_AWR_tuning_task');end;

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