关于oracle:Oracle-使用SqlProfile固定执行计划

明天给大家讲一下另外一种固定执行打算的办法：SqlProfile。

1. 获得不加 Hint 的执行打算。

SQL> conn test/test
接続されました。SQL> explain plan for select * from tab2 where c2=2;

解析されました。SQL> select * from table (dbms_xplan.display(format=>'advanced'));

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 2156729920

--------------------------------------------------------------------------
| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time     |
--------------------------------------------------------------------------
|   0 | SELECT STATEMENT  |      |    50 |   450 |     5   (0)| 00:00:01 |
|*  1 |  TABLE ACCESS FULL| TAB2 |    50 |   450 |     5   (0)| 00:00:01 |
--------------------------------------------------------------------------

Query Block Name / Object Alias (identified by operation id):
-------------------------------------------------------------

   1 - SEL$1 / TAB2@SEL$1

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

  /*+
      BEGIN_OUTLINE_DATA
      FULL(@"SEL$1" "TAB2"@"SEL$1")
      OUTLINE_LEAF(@"SEL$1")
      ALL_ROWS
      DB_VERSION('11.2.0.4')
      OPTIMIZER_FEATURES_ENABLE('11.2.0.4')
      IGNORE_OPTIM_EMBEDDED_HINTS
      END_OUTLINE_DATA
  */

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

   1 - filter("C2"=2)

Column Projection Information (identified by operation id):
-----------------------------------------------------------

   1 - "TAB2"."C1"[NUMBER,22], "C2"[NUMBER,22], "TAB2"."C3"[VARCHAR2,10]

37 行が選択されました。

2. 获得加 Hint 的执行打算。

SQL> explain plan for select /*+ index(tab2 ind2_2) */ * from tab2 where c2=2;

解析されました。SQL> select * from table (dbms_xplan.display(format=>'advanced'));

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 3201770281

--------------------------------------------------------------------------------------
| Id  | Operation                   | Name   | Rows  | Bytes | Cost (%CPU)| Time     |
--------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT            |        |    50 |   450 |    11   (0)| 00:00:01 |
|   1 |  TABLE ACCESS BY INDEX ROWID| TAB2   |    50 |   450 |    11   (0)| 00:00:01 |
|*  2 |   INDEX RANGE SCAN          | IND2_2 |    50 |       |     1   (0)| 00:00:01 |
--------------------------------------------------------------------------------------

Query Block Name / Object Alias (identified by operation id):
-------------------------------------------------------------

   1 - SEL$1 / TAB2@SEL$1
   2 - SEL$1 / TAB2@SEL$1

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

  /*+
      BEGIN_OUTLINE_DATA
      INDEX_RS_ASC(@"SEL$1" "TAB2"@"SEL$1" ("TAB2"."C2"))
      OUTLINE_LEAF(@"SEL$1")
      ALL_ROWS
      DB_VERSION('11.2.0.4')
      OPTIMIZER_FEATURES_ENABLE('11.2.0.4')
      IGNORE_OPTIM_EMBEDDED_HINTS
      END_OUTLINE_DATA
  */

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

   2 - access("C2"=2)

Column Projection Information (identified by operation id):
-----------------------------------------------------------

   1 - "TAB2"."C1"[NUMBER,22], "C2"[NUMBER,22], "TAB2"."C3"[VARCHAR2,10]
   2 - "TAB2".ROWID[ROWID,10], "C2"[NUMBER,22]

40 行が選択されました。

3. 把加 Hint 的执行打算做成 SqlProfile，固定给不加 Hint 的 SQL 文。

SQL> conn / as sysdba
接続されました。SQL> DECLARE
  2  sql_stmt clob;
  3  BEGIN
  4  sql_stmt:=q'^select * from tab2 where c2=2^';
  5  dbms_sqltune.import_sql_profile(
  6  sql_text => sql_stmt,
  7  name=>'test profile',
  8  profile => sqlprof_attr(q'^INDEX_RS_ASC(@"SEL$1""TAB2"@"SEL$1" ("TAB2"."C2"))^',
  9  q'^OUTLINE_LEAF(@"SEL$1")^',
 10  q'^ALL_ROWS^',
 11  q'^DB_VERSION('11.2.0.4')^',
 12  q'^OPTIMIZER_FEATURES_ENABLE('11.2.0.4')^',
 13  q'^IGNORE_OPTIM_EMBEDDED_HINTS^'),
 14  force_match=>true);
 15  end;
 16/

PL/SQL プロシージャが失常に完了しました。

4. 看看后果。

SQL> conn test/test
接続されました。SQL> set autot traceonly exp
SQL> set lin 120 pages 999
SQL> select * from tab2 where c2=2;

実行計画
----------------------------------------------------------
Plan hash value: 3201770281

--------------------------------------------------------------------------------------
| Id  | Operation                   | Name   | Rows  | Bytes | Cost (%CPU)| Time     |
--------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT            |        |    50 |   450 |    11   (0)| 00:00:01 |
|   1 |  TABLE ACCESS BY INDEX ROWID| TAB2   |    50 |   450 |    11   (0)| 00:00:01 |
|*  2 |   INDEX RANGE SCAN          | IND2_2 |    50 |       |     1   (0)| 00:00:01 |
--------------------------------------------------------------------------------------

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

   2 - access("C2"=2)

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