【测试】模拟一个全表扫描的sql，对其进行优化走索引，并且将执行计划稳定到baseLine。

①创建表t3：

SQL> create table t3 (id int);

Table created.

SQL> insert into t3 select level from dual connect by level<=100000;

100000 rows created.

②开启自动捕获并修改时间格式：

SQL> alter system set optimizer_capture_sql_plan_baselines=true; 

System altered.

SQL> alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';

Session altered.

③查询sql

SQL> select count(*) from t1 where id=1;

  COUNT(*)

----------

         2

SQL> select count(*) from t1 where id=1;

  COUNT(*)

----------

         2

SQL> select sql_handle,sql_text,plan_name,origin,version,created,last_modified,last_executed,last_verified,enabled,accepted,fixed from dba_sql_plan_baselines where sql_text like '%select count(*) from t1 where id=1%';

SQL_HANDLE

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

SQL_TEXT

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

PLAN_NAME                      ORIGIN

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

VERSION

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

CREATED

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

LAST_MODIFIED

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

LAST_EXECUTED

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

LAST_VERIFIED

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

ENA ACC FIX

--- --- ---

SQL_c0dca3d9bf76dcbd

select count(*) from t1 where id=1

SQL_PLAN_c1r53v6zrdr5x616acf47 AUTO-CAPTURE

11.2.0.4.0

17-OCT-16 02.56.20.000000 PM

17-OCT-16 02.56.20.000000 PM

17-OCT-16 02.56.20.000000 PM

YES YES NO

④创建索引：

SQL> create index idx_t1 on t1(id);

Index created.

⑤再次执行相同的sql语句：

SQL> select count(*) from t1 where id=1;

  COUNT(*)

----------

         2

SQL> select sql_handle,sql_text,plan_name,origin,version,created,last_modified,last_executed,last_verified,enabled,accepted,fixed from dba_sql_plan_baselines where sql_text like '%select count(*) from t1 where id=1%';

SQL_HANDLE

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

SQL_TEXT

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

PLAN_NAME                      ORIGIN

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

VERSION

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

CREATED

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

LAST_MODIFIED

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

LAST_EXECUTED

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

LAST_VERIFIED

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

ENA ACC FIX

--- --- ---

SQL_c0dca3d9bf76dcbd

select count(*) from t1 where id=1

SQL_PLAN_c1r53v6zrdr5x616acf47 AUTO-CAPTURE

11.2.0.4.0

17-OCT-16 02.56.20.000000 PM

17-OCT-16 02.56.20.000000 PM

17-OCT-16 02.56.20.000000 PM

YES YES NO

SQL_c0dca3d9bf76dcbd

select count(*) from t1 where id=1

SQL_PLAN_c1r53v6zrdr5xa9a6a0a8 AUTO-CAPTURE

11.2.0.4.0

17-OCT-16 02.59.07.000000 PM

17-OCT-16 02.59.07.000000 PM

YES NO  NO

⑥演进执行计划：

SQL> SET SERVEROUTPUT ON

SQL> SET LONG 10000

SQL> declare

  2  report clob;

  3  begin

  4  report :=DBMS_SPM.EVOLVE_SQL_PLAN_BASELINE(

  5  sql_handle => 'SQL_c0dca3d9bf76dcbd');

  6  DBMS_OUTPUT.PUT_LINE(report);

  7   END;

  8  /

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

--

                        Evolve SQL Plan Baseline

Report

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

--------

Inputs:

-------

  SQL_HANDLE = SQL_c0dca3d9bf76dcbd

  PLAN_NAME  =

TIME_LIMIT = DBMS_SPM.AUTO_LIMIT

  VERIFY     = YES

  COMMIT     = YES

Plan:

SQL_PLAN_c1r53v6zrdr5xa9a6a0a8

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

  Plan was

verified: Time used .09 seconds.

  Plan passed performance criterion: 153.86

times better than baseline plan.

  Plan was changed to an accepted plan.

Baseline Plan      Test Plan       Stats Ratio

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

  Execution Status:

COMPLETE       COMPLETE

  Rows Processed:                       1

1

  Elapsed Time(ms):                 4.149           .046              90.2

CPU Time(ms):                     4.221           .111             38.03

Buffer Gets:                        309              2             154.5

Physical Read Requests:               0              0

  Physical Write

Requests:              0              0

  Physical Read Bytes:

0              0

  Physical Write Bytes:                 0              0

Executions:                           1

1

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

----

                                 Report

Summary

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

---------

Number of plans verified: 1

Number of plans accepted: 1

PL/SQL procedure successfully completed.

⑦再次查看：

SQL> select sql_handle,sql_text,plan_name,origin,version,created,last_modified,last_executed,last_verified,enabled,accepted,fixed from dba_sql_plan_baselines where sql_text like '%select count(*) from t1 where id=1';

SQL_HANDLE

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

SQL_TEXT

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

PLAN_NAME                      ORIGIN

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

VERSION

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

CREATED

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

LAST_MODIFIED

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

LAST_EXECUTED

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

LAST_VERIFIED

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

ENA ACC FIX

--- --- ---

SQL_c0dca3d9bf76dcbd

select count(*) from t1 where id=1

SQL_PLAN_c1r53v6zrdr5x616acf47 AUTO-CAPTURE

11.2.0.4.0

17-OCT-16 02.56.20.000000 PM

17-OCT-16 02.56.20.000000 PM

17-OCT-16 02.56.20.000000 PM

YES YES NO

SQL_c0dca3d9bf76dcbd

select count(*) from t1 where id=1

SQL_PLAN_c1r53v6zrdr5xa9a6a0a8 AUTO-CAPTURE

11.2.0.4.0

17-OCT-16 02.59.07.000000 PM

17-OCT-16 03.02.17.000000 PM

17-OCT-16 03.02.17.000000 PM

YES YES NO

⑧查看现在查询所用的执行计划：

SQL> select count(*) from t1 where id=1;

Execution Plan

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

Plan hash value: 1970818898

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

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

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

|   0 | SELECT STATEMENT  |        |     1 |    13 |     1   (0)| 00:00:01 |

|   1 |  SORT AGGREGATE   |        |     1 |    13 |            |          |

|*  2 |   INDEX RANGE SCAN| IDX_T1 |     2 |    26 |     1   (0)| 00:00:01 |

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

Predicate Information (identified by operation id):

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

   2 - access("ID"=1)

Note

-----

   - dynamic sampling used for this statement (level=2)

   - SQL plan baseline "SQL_PLAN_c1r53v6zrdr5xa9a6a0a8" used for this statemen

t

Statistics

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

         29  recursive calls

         15  db block gets

         94  consistent gets

          0  physical reads

       3000  redo size

        526  bytes sent via SQL*Net to client

        524  bytes received via SQL*Net from client

          2  SQL*Net roundtrips to/from client

          0  sorts (memory)

          0  sorts (disk)

          1  rows processed

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【测试】模拟一个全表扫描的sql，对其进行优化走索引，并且将执行计划稳定到baseLine。

【测试】模拟一个全表扫描的sql，对其进行优化走索引，并且将执行计划稳定到baseLine。的更多相关文章

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