oracle 11g 自动调优

--:自动调优计划
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
  ---------
    为了选择好的执行计划, 优化程序需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可以改进此语句的执行计划。
  Recommendation (estimated benefit: 95.98%)
  ------------------------------------------
  - 考虑运行可以改进物理方案设计的访问指导或者创建推荐的索引。
    create index HJ.IDX$$_00360001 on HJ.DBTAN("OBJECT_TYPE");
  Rationale
  ---------
    创建推荐的索引可以显著地改进此语句的执行计划。但是, 使用典型的 SQL 工作量运行 "访问指导"
    可能比单个语句更可取。通过这种方法可以获得全面的索引建议案, 包括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;