Oracle利用coe_load_sql_profile指令碼繫結執行計劃

coe_load_sql_profile_v2.sql指令碼利用的是profile原理，只是做了半自動的形式來使用，下面是測試過程。

coe_load_sql_profile_v2.txt

建立環境，構建測試表：

SQL> create table t1 as select * from dba_objects where object_id is not null;

Table created.

SQL> alter table t1 modify object_id not null;

Table altered.

SQL> create index idx_t1_obj_id on t1(object_id);

Index created.

索引不儲存null值

SQL> analyze table t1 compute statistics;

Table analyzed.

SQL> select count(*) from t1;

  COUNT(*)

----------

     87070

SQL> select * from table(dbms_xplan.display_cursor(null,0));

PLAN_TABLE_OUTPUT

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

SQL_ID 12c0v4my7dvr3, child number 0

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

select count(*) from t1

Plan hash value: 1657298618

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

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

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

|   0 | SELECT STATEMENT  |      |      |      54 (100)|      |

|   1 |  SORT AGGREGAT    |      |     1 |       |      |

PLAN_TABLE_OUTPUT

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

|   2 |   INDEX FAST FULL SCAN| IDX_T1_OBJ_ID | 87070 |    54 (0)| 00:00:01 |

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

14 rows selected.

會發現是進行的索引快速掃描。

使用hint提示，強行走全表掃描，然後生成執行計劃。

SQL> select /*+ full(t1) */ count(*)from t1;

  COUNT(*)

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

     87070

SQL> select * from table(dbms_xplan.display_cursor(null,0));

PLAN_TABLE_OUTPUT

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

SQL_ID 20pat9zfypprh, child number 0

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

select /*+ full(t1) */ count(*)from t1

Plan hash value: 3724264953

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

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

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

|   0 | SELECT STATEMENT   |  |  |    347 (100)|    |

|   1 |  SORT AGGREGATE    |  | 1|          |    |

PLAN_TABLE_OUTPUT

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

|   2 |   TABLE ACCESS FULL| T1   | 87070 |   347   (1)| 00:00:05 |

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

14 rows selected.

SQL> @coe_load_sql_profile_v2.sql

Parameter 1:

SQL_ID (required)

Enter value for 1: 12c0v4my7dvr3

PLAN_HASH_VALUE AVG_ET_SECS

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

     1657298618        .141

Parameter 2:

PLAN_HASH_VALUE (required)

Enter value for 2: 3724264953

Values passed to coe_xfr_sql_profile:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

SQL_ID       : "12c0v4my7dvr3"

PLAN_HASH_VALUE: "3724264953"

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_12c0v4my7dvr3_3724264953.sql

on TARGET system in order to create a custom SQL Profile

with plan 3724264953 linked to adjusted sql_text.

.........省略

COE_XFR_SQL_PROFILE_12c0v4my7dvr3_3724264953 completed

COE_XFR_SQL_PROFILE completed.

SQL>explain plan for select count(*) from t1;

Explained.

SQL>select * from table(dbms_xplan.display());

PLAN_TABLE_OUTPUT

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

Plan hash value: 3724264953

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

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

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

|   0 | SELECT STATEMENT   |  | 1 |   347   (1)| 00:00:05 |

|   1 |  SORT AGGREGATE    |  | 1 |       |  |

|   2 |   TABLE ACCESS FULL| T1   | 87070 |   347   (1)| 00:00:05 |

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

Note

PLAN_TABLE_OUTPUT

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

-----

   - SQL profile "coe_12c0v4my7dvr3_3724264953" used for this statement

13 rows selected.

SQL> select name,category,status,sql_text from dba_sql_profiles;

NAME           CATEGORY   STATUS    SQL_TEXT

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

coe_12c0v4my7dvr3_3724264953   DEFAULT  ENABLED  select count(*) from t1

可以看到指令碼coe_load_sql_profile_v2.sql將執行計劃固定了。