Oracle 固定执行计划-使用SPM（Sql Plan Management）固定执行计划

固定执行计划-使用SPM（Sql Plan Management）固定执行计划

转载自：http://www.lunar2013.com/2016/01/固定执行计划-使用spm%EF%BC%88sql-plan-management%EF%BC%89固定执行计划.html

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固定执行计划-使用SQL Tuning Advisor
固定执行计划-手工指定PLAN OUTLINE
固定执行计划-手工指定索引名称的方式
固定执行计划-使用coe_xfr_sql_profile固定执行计划
固定执行计划-使用SPM（Sql Plan Management）固定执行计划
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在Oracle 11g前，我们可以借助存储大纲(Stored Outline)和SQL Profile来帮助我们固定某个SQL语句的执行计划。
11g中，Oracle 提供了SPM（Sql Plan Management）。
通过这个特性，可以考虑让Oracle自动去判断某个SQL的新的执行计划是否更加合理（成本更低），只有在新的执行计划比原来的执行计划更好才会被使用，从而保护了执行计划的稳定性和SQL语句的执行效率。
可以考虑手工捕获和自动捕获两种方式，这里我们采用手工捕获（11.2的缺省设置是非自动捕获）。
首先查看当前为禁止自动捕获的状态：

SYS@lunardb>show parameter optimizer_capture_sql_plan_baselines

 

NAME                                 TYPE        VALUE

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

optimizer_capture_sql_plan_baselines boolean     FALSE

SYS@lunardb>

当前SPM中没有内容：

LUNAR@lunardb>select signature,sql_handle,plan_name,origin,enabled,accepted,autopurge from dba_sql_plan_baselines;

 

no rows selected

 

Elapsed: 00:00:00.00

LUNAR@lunardb>

手工加载一个SQL到SPM中：

LUNAR@lunardb>declare

  2    l_plans_loaded  PLS_INTEGER;

  3  begin

  4    l_plans_loaded := DBMS_SPM.load_plans_from_cursor_cache(sql_id => '&sql_id');

  5    DBMS_OUTPUT.put_line('Plans Loaded: ' || l_plans_loaded);

  6  END;

  7  /

Enter value for sql_id: bjgduva68mbqm

old   4:   l_plans_loaded := DBMS_SPM.load_plans_from_cursor_cache(sql_id => '&sql_id');

new   4:   l_plans_loaded := DBMS_SPM.load_plans_from_cursor_cache(sql_id => 'bjgduva68mbqm');

Plans Loaded: 1

 

PL/SQL procedure successfully completed.

 

Elapsed: 00:00:00.21

LUNAR@lunardb>

LUNAR@lunardb>select signature,sql_handle,plan_name,origin,enabled,accepted,autopurge from dba_sql_plan_baselines;

 

       SIGNATURE SQL_HANDLE                     PLAN_NAME                      ORIGIN         ENA ACC AUT

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

6.5941520220E+17 SQL_0926b6a1f69f6f5c           SQL_PLAN_0k9pqn7v9yvuw02b73393 MANUAL-LOAD    YES YES YES

 

Elapsed: 00:00:00.01

LUNAR@lunardb>

由于上一个测试，我们已经有了正确的执行计划，即：

LUNAR@lunardb>select * from table(dbms_xplan.display_cursor(sql_id=>'bjgduva68mbqm')) where plan_table_output  like ('Plan hash value%');

 

PLAN_TABLE_OUTPUT

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

Plan hash value: 3241900148

 

Elapsed: 00:00:00.02

LUNAR@lunardb>

LUNAR@lunardb>select SQL_HANDLE, PLAN_NAME, ENABLED, ACCEPTED, SQL_TEXT

  2  from DBA_SQL_PLAN_BASELINES

  3  where ACCEPTED = 'YES'

  4  order by LAST_MODIFIED;

 

SQL_HANDLE                     PLAN_NAME                      ENA ACC SQL_TEXT

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

SQL_0926b6a1f69f6f5c           SQL_PLAN_0k9pqn7v9yvuw02b73393 YES YES select /*+ no_index(lunartest1 idx_lunartest1_n) */ * from lunartest1 where n=1

 

Elapsed: 00:00:00.01

LUNAR@lunardb>

下面，我们装载指定的执行计划：

LUNAR@lunardb>variable cnt number ;

LUNAR@lunardb>exec :cnt :=dbms_spm.LOAD_PLANS_FROM_CURSOR_CACHE (SQL_ID => '&SQL_ID',PLAN_HASH_VALUE => &plan_hash_value, SQL_HANDLE => '&SQL_HANDLE' ) ;

Enter value for sql_id: bjgduva68mbqm

Enter value for plan_hash_value: 1172089107

Enter value for sql_handle: SQL_0926b6a1f69f6f5c

 

PL/SQL procedure successfully completed.

 

Elapsed: 00:00:00.02

LUNAR@lunardb>select signature,sql_handle,plan_name,origin,enabled,accepted,autopurge

  2  from dba_sql_plan_baselines where CREATED>sysdate-1/48 order by created;

 

             SIGNATURE SQL_HANDLE                     PLAN_NAME                      ORIGIN         ENA ACC AUT

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

    659415202199990108 SQL_0926b6a1f69f6f5c           SQL_PLAN_0k9pqn7v9yvuw02b73393 MANUAL-LOAD    YES YES YES

 

Elapsed: 00:00:00.00

LUNAR@lunardb>

确认该执行计划的OUTLINE：

LUNAR@lunardb>SELECT extractValue(value(h),'.') AS hint

  2  FROM sys.sqlobj$data od, sys.sqlobj$ so,

  3  table(xmlsequence(extract(xmltype(od.comp_data),'/outline_data/hint'))) h

  4  WHERE so.name = 'SQL_PLAN_0k9pqn7v9yvuw02b73393'

  5  AND so.signature = od.signature

  6  AND so.category = od.category

  7  AND so.obj_type = od.obj_type

  8  AND so.plan_id = od.plan_id;

 

HINT

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

IGNORE_OPTIM_EMBEDDED_HINTS

OPTIMIZER_FEATURES_ENABLE('11.2.0.4')

DB_VERSION('11.2.0.4')

ALL_ROWS

OUTLINE_LEAF(@"SEL$1")

INDEX(@"SEL$1" "LUNARTEST1"@"SEL$1" ("LUNARTEST1"."N"))

 

6 rows selected.

 

Elapsed: 00:00:00.08

LUNAR@lunardb>

这里看到是我们需要的走索引的outline，详细的OUTLINE信息如下:

LUNAR@lunardb>SELECT extractValue(value(h),'.') AS hint

  2  FROM sys.sqlobj$data od, sys.sqlobj$ so,

  3  table(xmlsequence(extract(xmltype(od.comp_data),'/outline_data/hint'))) h

  4  WHERE so.signature = '659415202199990108'

  5  AND so.signature = od.signature

  6  AND so.category = od.category

  7  AND so.obj_type = od.obj_type

  8  AND so.plan_id = od.plan_id;

 

HINT

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

BEGIN_OUTLINE_DATA

IGNORE_OPTIM_EMBEDDED_HINTS

OPTIMIZER_FEATURES_ENABLE('11.2.0.4')

DB_VERSION('11.2.0.4')

ALL_ROWS

OUTLINE_LEAF(@"SEL$1")

INDEX(@"SEL$1" "LUNARTEST1"@"SEL$1" ("LUNARTEST1"."N"))

END_OUTLINE_DATA

IGNORE_OPTIM_EMBEDDED_HINTS

OPTIMIZER_FEATURES_ENABLE('11.2.0.4')

DB_VERSION('11.2.0.4')

ALL_ROWS

OUTLINE_LEAF(@"SEL$1")

INDEX(@"SEL$1" "LUNARTEST1"@"SEL$1" ("LUNARTEST1"."N"))

 

14 rows selected.

 

Elapsed: 00:00:00.10

LUNAR@lunardb>   

现在我们删除profile以前用coe绑定的sql profile：

LUNAR@lunardb>SELECT * FROM DBA_SQL_PROFILES;

 

NAME                           CATEGORY                                    SIGNATURE SQL_TEXT

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

CREATED                                                                     LAST_MODIFIED

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

DESCRIPTION

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

TYPE    STATUS   FOR          TASK_ID TASK_EXEC_NAME                      TASK_OBJ_ID      TASK_FND_ID      TASK_REC_ID

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

coe_bjgduva68mbqm_3241900148   DEFAULT                            659415202199990108 select /*+ no_index(lunartest1 idx_lunartest1_n) */ * from lunartest1 where n=1

12-JAN-16 11.24.18.000000 AM                                                12-JAN-16 11.40.52.000000 AM

coe bjgduva68mbqm 3241900148 659415202199990108 9900816299026594015

MANUAL  ENABLED  NO

 

 

Elapsed: 00:00:00.01

LUNAR@lunardb>

LUNAR@lunardb>exec dbms_sqltune.drop_sql_profile('coe_bjgduva68mbqm_3241900148');

 

PL/SQL procedure successfully completed.

 

Elapsed: 00:00:00.01

LUNAR@lunardb>SELECT * FROM DBA_SQL_PROFILES;

 

no rows selected

 

Elapsed: 00:00:00.00

LUNAR@lunardb>

再次验证SPM的执行计划：

LUNAR@lunardb>select * from table(dbms_xplan.DISPLAY_SQL_PLAN_BASELINE('&sql_handle','&PLAN_NAME'));

Enter value for sql_handle: SQL_0926b6a1f69f6f5c

Enter value for plan_name: SQL_PLAN_0k9pqn7v9yvuw02b73393

old   1: select * from table(dbms_xplan.DISPLAY_SQL_PLAN_BASELINE('&sql_handle','&PLAN_NAME'))

new   1: select * from table(dbms_xplan.DISPLAY_SQL_PLAN_BASELINE('SQL_0926b6a1f69f6f5c','SQL_PLAN_0k9pqn7v9yvuw02b73393'))

 

PLAN_TABLE_OUTPUT

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

 

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

SQL handle: SQL_0926b6a1f69f6f5c

SQL text: select /*+ no_index(lunartest1 idx_lunartest1_n) */ * from lunartest1

          where n=1

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

 

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

Plan name: SQL_PLAN_0k9pqn7v9yvuw02b73393         Plan id: 45560723

Enabled: YES     Fixed: NO      Accepted: YES     Origin: MANUAL-LOAD

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

 

Plan hash value: 3241900148

 

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

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

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

|   0 | SELECT STATEMENT |                  |     1 |     4 |     1   (0)| 00:00:01 |

|*  1 |  INDEX RANGE SCAN| IDX_LUNARTEST1_N |     1 |     4 |     1   (0)| 00:00:01 |

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

 

Predicate Information (identified by operation id):

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

 

   1 - access("N"=1)

 

25 rows selected.

 

Elapsed: 00:00:00.16

LUNAR@lunardb>

执行SQL，发现SPM可以固定执行计划，使用了我们期待的：

LUNAR@lunardb>set autotrace traceo exp stat

LUNAR@lunardb>select /*+ no_index(lunartest1 idx_lunartest1_n) */ * from lunartest1 where n=1;

 

Elapsed: 00:00:00.13

 

Execution Plan

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

Plan hash value: 3241900148

 

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

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

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

|   0 | SELECT STATEMENT |                  |     1 |     4 |     1   (0)| 00:00:01 |

|*  1 |  INDEX RANGE SCAN| IDX_LUNARTEST1_N |     1 |     4 |     1   (0)| 00:00:01 |

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

 

Predicate Information (identified by operation id):

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

 

   1 - access("N"=1)

 

Note

-----

   - SQL plan baseline "SQL_PLAN_0k9pqn7v9yvuw02b73393" used for this statement

 

 

Statistics

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

         59  recursive calls

         52  db block gets

         36  consistent gets

          1  physical reads

      15312  redo size

        519  bytes sent via SQL*Net to client

        523  bytes received via SQL*Net from client

          2  SQL*Net roundtrips to/from client

          0  sorts (memory)

          0  sorts (disk)

          1  rows processed

 

LUNAR@lunardb>

这里看到已经使用了SPM中的SQL Profile：SQL_PLAN_0k9pqn7v9yvuw02b73393
总结：
这里已经使用了我们的SPM(SQL_PLAN_0k9pqn7v9yvuw02b73393)固定了执行计划，sql使用了索引
说明SPM绑定执行计划的方式比hint的优先级高