使用coe脚本固定执行计划和手工指定profile的outline的方式有什么区别？

发表于 2014 年 6 月 29 日 由 Lunar

联系：QQ(5163721)

标题：使用coe脚本固定执行计划和手工指定profile的outline的方式有什么区别？

作者：Lunar©版权所有[文章允许转载,但必须以链接方式注明源地址,否则追究法律责任.]

测试目的：
1，假设下面的两个语句分别为A语句和B语句：
A语句： select count(*) from lunar where extent_id=1;
B语句： select /*+ FULL(lunar) */ count(*) from lunar where extent_id=1;
2，使用coe的脚本（在SQLT中可以知道整套coe脚本）手工为A语句指定B语句的执行计划，看看什么效果
（即，让原本正常走索引的A语句使用全表扫描的B语句的执行计划）

3，使用dbms_sqltune.import_sql_profile为A语句指定执行计划，看看什么效果

首先，做一个测试表：

[oracle@lunar /]$ ss

SQL*Plus: Release 11.2.0.3.0 Production on Sat Jun 7 21:29:52 2014

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

Welcome Lunar's oracle world!

Love you , baby !

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning and Real Application Testing options

SYS@lunar>conn lunar/lunar
Welcome Lunar's oracle world!

Love you , baby !

Connected.
LUNAR@lunar>create table lunar as select * from dba_extents;

Table created.

Elapsed: 00:00:04.61

在extent_id列上创建非唯一索引：

LUNAR@lunar>create index idx_lunar_extent_id on lunar(extent_id) ;

Index created.

Elapsed: 00:00:00.02

LUNAR@lunar>EXEC DBMS_STATS.GATHER_TABLE_STATS(OWNNAME => 'LUNAR',TABNAME => 'LUNAR',DEGREE => 5,
 2  CASCADE => TRUE,ESTIMATE_PERCENT => DBMS_STATS.AUTO_SAMPLE_SIZE);

PL/SQL procedure successfully completed.

Elapsed: 00:00:01.45

可以看到下面的语句正确的使用了索引（把这条语句称之为A语句）：

LUNAR@lunar>select count(*) from lunar where extent_id=1;

  COUNT(*)
----------
       323

Elapsed: 00:00:00.01

Execution Plan
----------------------------------------------------------
Plan hash value: 1050880347  ---这里是A语句的执行计划的plan hash value

-----------------------------------------------------------------------------------------
| Id  | Operation         | Name                | Rows  | Bytes | Cost (%CPU)| Time     |
-----------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT  |                     |     1 |     3 |     1   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE   |                     |     1 |     3 |            |          |
|*  2 |   INDEX RANGE SCAN| IDX_LUNAR_EXTENT_ID |    84 |   252 |     1   (0)| 00:00:01 |
-----------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - access("EXTENT_ID"=1)


Statistics
----------------------------------------------------------
          1  recursive calls
          0  db block gets
          3  consistent gets
          0  physical reads
          0  redo size
        527  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

LUNAR@lunar>

我使用hint指定该语句必须走全表扫描，姑且把这条语句称为B语句：

LUNAR@lunar>select /*+ FULL(lunar) */ count(*) from lunar where extent_id=1;

  COUNT(*)
----------
       323

Elapsed: 00:00:00.02

Execution Plan
----------------------------------------------------------
Plan hash value: 291688323  ---这里是B语句的执行计划的plan hash value

----------------------------------------------------------------------------
| Id  | Operation          | Name  | Rows  | Bytes | Cost (%CPU)| Time     |
----------------------------------------------------------------------------
|   0 | SELECT STATEMENT   |       |     1 |     3 |    16   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE    |       |     1 |     3 |            |          |
|*  2 |   TABLE ACCESS FULL| LUNAR |    84 |   252 |    16   (0)| 00:00:01 |
----------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - filter("EXTENT_ID"=1)


Statistics
----------------------------------------------------------
          1  recursive calls
          0  db block gets
         50  consistent gets
          0  physical reads
          0  redo size
        527  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

LUNAR@lunar>

找到A语句和B语句的sql_id:

LUNAR@lunar>select sql_id from v$sql where sql_text like '%FULL(lunar)%'; 

SQL_ID
-------------
078qb40kcsnnu
7f8h3z6pj9w52
05538tk3vkzu3

Elapsed: 00:00:00.10

LUNAR@lunar>select sql_id,sql_text from v$sql where sql_text like '%extent_id=1%'; 

SQL_ID
-------------
SQL_TEXT
----------------------------------------------------------------------------------------------------------------------------------------------------
078qb40kcsnnu
EXPLAIN PLAN SET STATEMENT_ID='PLUS271153' FOR select /*+ FULL(lunar) */ count(*) from lunar where extent_id=1

39sr1xpxpkbmv
select sql_id,sql_text from v$sql where sql_text like '%extent_id=1%'

05538tk3vkzu3  ---------注意，这里是B语句的sql_id
select /*+ FULL(lunar) */ count(*) from lunar where extent_id=1

fvrmp2a2t38dc  ---------注意，这里是A语句的sql_id
select count(*) from lunar where extent_id=1

g4bcvwhrgradr
EXPLAIN PLAN SET STATEMENT_ID='PLUS271153' FOR select count(*) from lunar where extent_id=1

g4bcvwhrgradr
EXPLAIN PLAN SET STATEMENT_ID='PLUS271153' FOR select count(*) from lunar where extent_id=1


6 rows selected.

Elapsed: 00:00:00.03
LUNAR@lunar>

使用coe的脚本来固定执行计划，291688323是B语句的执行计划：

LUNAR@lunar>@coe_xfr_sql_profile fvrmp2a2t38dc 291688323

Parameter 1:
SQL_ID (required)



PLAN_HASH_VALUE AVG_ET_SECS
--------------- -----------
     1050880347        .039

Parameter 2:
PLAN_HASH_VALUE (required)


Values passed to coe_xfr_sql_profile:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SQL_ID         : "fvrmp2a2t38dc"
PLAN_HASH_VALUE: "291688323"

SQL>BEGIN
  2    IF :sql_text IS NULL THEN
  3      RAISE_APPLICATION_ERROR(-20100, 'SQL_TEXT for SQL_ID &&sql_id. was not found in memory (gv$sqltext_with_newlines) or AWR (dba_hist_sqltext).');
  4    END IF;
  5  END;
  6  /
SQL>SET TERM OFF;
SQL>BEGIN
  2    IF :other_xml IS NULL THEN
  3      RAISE_APPLICATION_ERROR(-20101, 'PLAN for SQL_ID &&sql_id. and PHV &&plan_hash_value. was not found in memory (gv$sql_plan) or AWR (dba_hist_sql_plan).');
  4    END IF;
  5  END;
  6  /
SQL>SET TERM OFF;

Execute coe_xfr_sql_profile_fvrmp2a2t38dc_291688323.sql
on TARGET system in order to create a custom SQL Profile
with plan 291688323 linked to adjusted sql_text.


COE_XFR_SQL_PROFILE completed.
SQL>@coe_xfr_sql_profile_fvrmp2a2t38dc_291688323.sql
SQL>REM
SQL>REM $Header: 215187.1 coe_xfr_sql_profile_fvrmp2a2t38dc_291688323.sql 11.4.4.4 2014/06/08 carlos.sierra $
SQL>REM
SQL>REM Copyright (c) 2000-2012, Oracle Corporation. All rights reserved.
SQL>REM
SQL>REM AUTHOR
SQL>REM   carlos.sierra@oracle.com
SQL>REM
SQL>REM SCRIPT
SQL>REM   coe_xfr_sql_profile_fvrmp2a2t38dc_291688323.sql
SQL>REM
SQL>REM DESCRIPTION
SQL>REM   This script is generated by coe_xfr_sql_profile.sql
SQL>REM   It contains the SQL*Plus commands to create a custom
SQL>REM   SQL Profile for SQL_ID fvrmp2a2t38dc based on plan hash
SQL>REM   value 291688323.
SQL>REM   The custom SQL Profile to be created by this script
SQL>REM   will affect plans for SQL commands with signature
SQL>REM   matching the one for SQL Text below.
SQL>REM   Review SQL Text and adjust accordingly.
SQL>REM
SQL>REM PARAMETERS
SQL>REM   None.
SQL>REM
SQL>REM EXAMPLE
SQL>REM   SQL> START coe_xfr_sql_profile_fvrmp2a2t38dc_291688323.sql;
SQL>REM
SQL>REM NOTES
SQL>REM   1. Should be run as SYSTEM or SYSDBA.
SQL>REM   2. User must have CREATE ANY SQL PROFILE privilege.
SQL>REM   3. SOURCE and TARGET systems can be the same or similar.
SQL>REM   4. To drop this custom SQL Profile after it has been created:
SQL>REM  EXEC DBMS_SQLTUNE.DROP_SQL_PROFILE('coe_fvrmp2a2t38dc_291688323');
SQL>REM   5. Be aware that using DBMS_SQLTUNE requires a license
SQL>REM  for the Oracle Tuning Pack.
SQL>REM   6. If you modified a SQL putting Hints in order to produce a desired
SQL>REM  Plan, you can remove the artifical Hints from SQL Text pieces below.
SQL>REM  By doing so you can create a custom SQL Profile for the original
SQL>REM  SQL but with the Plan captured from the modified SQL (with Hints).
SQL>REM
SQL>WHENEVER SQLERROR EXIT SQL.SQLCODE;
SQL>REM
SQL>VAR signature NUMBER;
SQL>VAR signaturef NUMBER;
SQL>REM
SQL>DECLARE
  2  sql_txt CLOB;
  3  h       SYS.SQLPROF_ATTR;
  4  PROCEDURE wa (p_line IN VARCHAR2) IS
  5  BEGIN
  6  DBMS_LOB.WRITEAPPEND(sql_txt, LENGTH(p_line), p_line);
  7  END wa;
  8  BEGIN
  9  DBMS_LOB.CREATETEMPORARY(sql_txt, TRUE);
 10  DBMS_LOB.OPEN(sql_txt, DBMS_LOB.LOB_READWRITE);
 11  -- SQL Text pieces below do not have to be of same length.
 12  -- So if you edit SQL Text (i.e. removing temporary Hints),
 13  -- there is no need to edit or re-align unmodified pieces.
 14  wa(q'[select count(*) from lunar where extent_id=1]');
 15  DBMS_LOB.CLOSE(sql_txt);
 16  h := SYS.SQLPROF_ATTR(
 17  q'[BEGIN_OUTLINE_DATA]',
 18  q'[IGNORE_OPTIM_EMBEDDED_HINTS]',
 19  q'[OPTIMIZER_FEATURES_ENABLE('11.2.0.3')]',
 20  q'[DB_VERSION('11.2.0.3')]',
 21  q'[ALL_ROWS]',
 22  q'[OUTLINE_LEAF(@"SEL$F5BB74E1")]',
 23  q'[MERGE(@"SEL$2")]',
 24  q'[OUTLINE(@"SEL$1")]',
 25  q'[OUTLINE(@"SEL$2")]',
 26  q'[FULL(@"SEL$F5BB74E1" "LUNAR"@"SEL$2")]',
 27  q'[END_OUTLINE_DATA]');
 28  :signature := DBMS_SQLTUNE.SQLTEXT_TO_SIGNATURE(sql_txt);
 29  :signaturef := DBMS_SQLTUNE.SQLTEXT_TO_SIGNATURE(sql_txt, TRUE);
 30  DBMS_SQLTUNE.IMPORT_SQL_PROFILE (
 31  sql_text    => sql_txt,
 32  profile     => h,
 33  name        => 'coe_fvrmp2a2t38dc_291688323',
 34  description => 'coe fvrmp2a2t38dc 291688323 '||:signature||' '||:signaturef||'',
 35  category    => 'DEFAULT',
 36  validate    => TRUE,
 37  replace     => TRUE,
 38  force_match => FALSE /* TRUE:FORCE (match even when different literals in SQL). FALSE:EXACT (similar to CURSOR_SHARING) */ );
 39  DBMS_LOB.FREETEMPORARY(sql_txt);
 40  END;
 41  /

PL/SQL procedure successfully completed.

SQL>WHENEVER SQLERROR CONTINUE
SQL>SET ECHO OFF;

            SIGNATURE
---------------------
 12989549146262258752


           SIGNATUREF
---------------------
 11568928226314596944


... manual custom SQL Profile has been created


COE_XFR_SQL_PROFILE_fvrmp2a2t38dc_291688323 completed
SQL>

根据提示执行COE_XFR_SQL_PROFILE_fvrmp2a2t38dc_291688323.sql脚本:

SQL>@coe_xfr_sql_profile_fvrmp2a2t38dc_291688323.sql
SQL>REM
SQL>REM $Header: 215187.1 coe_xfr_sql_profile_fvrmp2a2t38dc_291688323.sql 11.4.4.4 2014/06/08 carlos.sierra $
SQL>REM
SQL>REM Copyright (c) 2000-2012, Oracle Corporation. All rights reserved.
SQL>REM
SQL>REM AUTHOR
SQL>REM   carlos.sierra@oracle.com
SQL>REM
SQL>REM SCRIPT
SQL>REM   coe_xfr_sql_profile_fvrmp2a2t38dc_291688323.sql
SQL>REM
SQL>REM DESCRIPTION
SQL>REM   This script is generated by coe_xfr_sql_profile.sql
SQL>REM   It contains the SQL*Plus commands to create a custom
SQL>REM   SQL Profile for SQL_ID fvrmp2a2t38dc based on plan hash
SQL>REM   value 291688323.
SQL>REM   The custom SQL Profile to be created by this script
SQL>REM   will affect plans for SQL commands with signature
SQL>REM   matching the one for SQL Text below.
SQL>REM   Review SQL Text and adjust accordingly.
SQL>REM
SQL>REM PARAMETERS
SQL>REM   None.
SQL>REM
SQL>REM EXAMPLE
SQL>REM   SQL> START coe_xfr_sql_profile_fvrmp2a2t38dc_291688323.sql;
SQL>REM
SQL>REM NOTES
SQL>REM   1. Should be run as SYSTEM or SYSDBA.
SQL>REM   2. User must have CREATE ANY SQL PROFILE privilege.
SQL>REM   3. SOURCE and TARGET systems can be the same or similar.
SQL>REM   4. To drop this custom SQL Profile after it has been created:
SQL>REM  EXEC DBMS_SQLTUNE.DROP_SQL_PROFILE('coe_fvrmp2a2t38dc_291688323');
SQL>REM   5. Be aware that using DBMS_SQLTUNE requires a license
SQL>REM  for the Oracle Tuning Pack.
SQL>REM   6. If you modified a SQL putting Hints in order to produce a desired
SQL>REM  Plan, you can remove the artifical Hints from SQL Text pieces below.
SQL>REM  By doing so you can create a custom SQL Profile for the original
SQL>REM  SQL but with the Plan captured from the modified SQL (with Hints).
SQL>REM
SQL>WHENEVER SQLERROR EXIT SQL.SQLCODE;
SQL>REM
SQL>VAR signature NUMBER;
SQL>VAR signaturef NUMBER;
SQL>REM
SQL>DECLARE
  2  sql_txt CLOB;
  3  h       SYS.SQLPROF_ATTR;
  4  PROCEDURE wa (p_line IN VARCHAR2) IS
  5  BEGIN
  6  DBMS_LOB.WRITEAPPEND(sql_txt, LENGTH(p_line), p_line);
  7  END wa;
  8  BEGIN
  9  DBMS_LOB.CREATETEMPORARY(sql_txt, TRUE);
 10  DBMS_LOB.OPEN(sql_txt, DBMS_LOB.LOB_READWRITE);
 11  -- SQL Text pieces below do not have to be of same length.
 12  -- So if you edit SQL Text (i.e. removing temporary Hints),
 13  -- there is no need to edit or re-align unmodified pieces.
 14  wa(q'[select count(*) from lunar where extent_id=1]');
 15  DBMS_LOB.CLOSE(sql_txt);
 16  h := SYS.SQLPROF_ATTR(
 17  q'[BEGIN_OUTLINE_DATA]',
 18  q'[IGNORE_OPTIM_EMBEDDED_HINTS]',
 19  q'[OPTIMIZER_FEATURES_ENABLE('11.2.0.3')]',
 20  q'[DB_VERSION('11.2.0.3')]',
 21  q'[ALL_ROWS]',
 22  q'[OUTLINE_LEAF(@"SEL$F5BB74E1")]',
 23  q'[MERGE(@"SEL$2")]',
 24  q'[OUTLINE(@"SEL$1")]',
 25  q'[OUTLINE(@"SEL$2")]',
 26  q'[FULL(@"SEL$F5BB74E1" "LUNAR"@"SEL$2")]',
 27  q'[END_OUTLINE_DATA]');
 28  :signature := DBMS_SQLTUNE.SQLTEXT_TO_SIGNATURE(sql_txt);
 29  :signaturef := DBMS_SQLTUNE.SQLTEXT_TO_SIGNATURE(sql_txt, TRUE);
 30  DBMS_SQLTUNE.IMPORT_SQL_PROFILE (
 31  sql_text    => sql_txt,
 32  profile     => h,
 33  name        => 'coe_fvrmp2a2t38dc_291688323',
 34  description => 'coe fvrmp2a2t38dc 291688323 '||:signature||' '||:signaturef||'',
 35  category    => 'DEFAULT',
 36  validate    => TRUE,
 37  replace     => TRUE,
 38  force_match => FALSE /* TRUE:FORCE (match even when different literals in SQL). FALSE:EXACT (similar to CURSOR_SHARING) */ );
 39  DBMS_LOB.FREETEMPORARY(sql_txt);
 40  END;
 41  /

PL/SQL procedure successfully completed.

SQL>WHENEVER SQLERROR CONTINUE
SQL>SET ECHO OFF;

            SIGNATURE
---------------------
 12989549146262258752


           SIGNATUREF
---------------------
 11568928226314596944


... manual custom SQL Profile has been created


COE_XFR_SQL_PROFILE_fvrmp2a2t38dc_291688323 completed

再次查询，验证一下A语句是否已经按照我们指定的那样采用了B语句的全表扫描的执行计划：

SQL>select count(*) from lunar where extent_id=1;

  COUNT(*)
----------
       323


Execution Plan
----------------------------------------------------------
Plan hash value: 1050880347

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

| Id  | Operation         | Name                | Rows  | Bytes | Cost (%CPU)| T
ime     |

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

|   0 | SELECT STATEMENT  |                     |     1 |     3 |     1   (0)| 0
0:00:01 |

|   1 |  SORT AGGREGATE   |                     |     1 |     3 |            |
        |

|*  2 |   INDEX RANGE SCAN| IDX_LUNAR_EXTENT_ID |    84 |   252 |     1   (0)| 0
0:00:01 |

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


Predicate Information (identified by operation id):
---------------------------------------------------

   2 - access("EXTENT_ID"=1)

Note
-----
   - SQL profile "coe_fvrmp2a2t38dc_291688323" used for this statement


Statistics
----------------------------------------------------------
          1  recursive calls
          0  db block gets
          3  consistent gets
          0  physical reads
          0  redo size
        527  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

SQL>

结论：我们的猜测是错误的，使用coe的脚本固定执行计划，必须是从该sql_id的已经有的所有执行计划中挑选其一，而不能凭空指定一个你认为合适的。

下面，我们使用其他方法固定SQL的执行计划。首先找出B语句的执行计划和outline：

SQL>set lines 1000
SQL>set pages 10000
SQL>select * from table(dbms_xplan.display_cursor('05538tk3vkzu3',null,'outline'));

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SQL_ID  05538tk3vkzu3, child number 0
-------------------------------------
select /*+ FULL(lunar) */ count(*) from lunar where extent_id=1

Plan hash value: 291688323

----------------------------------------------------------------------------
| Id  | Operation          | Name  | Rows  | Bytes | Cost (%CPU)| Time     |
----------------------------------------------------------------------------
|   0 | SELECT STATEMENT   |       |       |       |    16 (100)|          |
|   1 |  SORT AGGREGATE    |       |     1 |     3 |            |          |
|*  2 |   TABLE ACCESS FULL| LUNAR |    84 |   252 |    16   (0)| 00:00:01 |
----------------------------------------------------------------------------

Outline Data
-------------

  /*+
      BEGIN_OUTLINE_DATA
      IGNORE_OPTIM_EMBEDDED_HINTS
      OPTIMIZER_FEATURES_ENABLE('11.2.0.3')
      DB_VERSION('11.2.0.3')
      ALL_ROWS
      OUTLINE_LEAF(@"SEL$1")
      FULL(@"SEL$1" "LUNAR"@"SEL$1")
      END_OUTLINE_DATA
  */

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - filter("EXTENT_ID"=1)


33 rows selected.

SQL>

使用下面的脚本为A语句指定B语句的outline：

LUNAR@lunar>declare
  2  v_hints sys.sqlprof_attr;
  3  sql_txt clob;
  4  begin 
  5  v_hints:=sys.sqlprof_attr(
  6        'BEGIN_OUTLINE_DATA',
  7        'IGNORE_OPTIM_EMBEDDED_HINTS',
  8        'OPTIMIZER_FEATURES_ENABLE(''11.2.0.3'')',
  9        'DB_VERSION(''11.2.0.3'')',
 10        'ALL_ROWS',
 11        'OUTLINE_LEAF(@"SEL$1")',
 12        'FULL(@"SEL$1" "LUNAR"@"SEL$1")',
 13        'END_OUTLINE_DATA'
 14  );
 15    select sql_fulltext into sql_txt from v$sql where sql_id='fvrmp2a2t38dc';
 16    dbms_sqltune.import_sql_profile(sql_text => sql_txt,
 17    profile => v_hints,name => 'SQLPROF_Lunar',
 18    replace => TRUE,force_match => TRUE);
 19  end;
 20  /

PL/SQL procedure successfully completed.

Elapsed: 00:00:00.19
LUNAR@lunar>

再次测试，发现语句A已经采用了我们指定的outline，即使用了B语句的全表扫描的执行计划：
LUNAR@lunar>select count(*) from lunar where extent_id=1;

  COUNT(*)
----------
       323

Elapsed: 00:00:00.02

Execution Plan
----------------------------------------------------------
Plan hash value: 291688323

----------------------------------------------------------------------------
| Id  | Operation          | Name  | Rows  | Bytes | Cost (%CPU)| Time     |
----------------------------------------------------------------------------
|   0 | SELECT STATEMENT   |       |     1 |     3 |    16   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE    |       |     1 |     3 |            |          |
|*  2 |   TABLE ACCESS FULL| LUNAR |    84 |   252 |    16   (0)| 00:00:01 |
----------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - filter("EXTENT_ID"=1)

Note
-----
   - SQL profile "SQLPROF_Lunar" used for this statement  注意，这里已经采用了SQLPROF_Lunar


Statistics
----------------------------------------------------------
         10  recursive calls
          0  db block gets
         57  consistent gets
          1  physical reads
          0  redo size
        527  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

LUNAR@lunar>

结论：
1，使用coe的脚本固定执行计划，必须是从该sql_id的已经有的所有执行计划中挑选其一，而不能凭空指定一个你认为合适的。
因此，如果需要从某条sql已经执行过的执行计划中挑选一个合适的，那么coe的脚本简单轻巧，非常合适。

2，如果要手工构造一个该SQL语句从未使用的执行计划，可以采用dbms_sqltune.import_sql_profile的方式手工设置outline，从而改变执行计划。
在这种需求下，coe的脚本是无能为力的。

此条目发表在 Performence Tuning 分类目录，贴了 , , 标签。将固定链接加入收藏夹。

《使用coe脚本固定执行计划和手工指定profile的outline的方式有什么区别？》有 5 条评论

  1. Lonion 说：
    2014 年 7 月 8 日22:17

    关于结论2，可以参考崔华的<> P181，里面有提到一个“偷梁换柱”的概念，是关于如何使用coe_xfr_sql_profile.sql 将A语句的执行计划改为B语句的执行计划。

    我觉得你的方法和他的方法整体上是一样的。

    回复
  2. Lonion 说：
    2014 年 7 月 8 日22:18

    晕，书名被过滤了。《基于Oracle的SQL优化》

    回复
  3. ronwa 说：
    2015 年 1 月 5 日17:40

    关于结论2，
    你可以加提示生成另外一个的执行计划，SQL_ID当然不一样。再通过COE脚本偷梁换柱。
    http://cronwa.blog.163.com/blog/static/13666671420146161926398/
    通过脚本快速创建sql profile , 分分钟搞定。

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  4. ronwa 说：
    2015 年 1 月 5 日17:45

    对于当前不存在的执行计划，加HINT执行生成一个即可。SQL_ID不一样没关系。
    通过SHELL脚本来偷梁换柱，一分钟内搞定。
    http://cronwa.blog.163.com/blog/static/13666671420146161926398/

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