Oracle 使用 sql profile 固定执行计划

测试使用 sql profile 固定执行计划：

Oracle 10g之前有outlines,10g之后 sql profile 。如果针对非绑定变量的sql,outlines则效果不佳，不建议使用。

1、准备测试用表

SQL> create table zzh_ob as select * from dba_objects;

SQL> create index ind_obid on zzh_ob(object_id);

SQL> select object_id from zzh_ob where rownum<2;

OBJECT_ID

SQL> exec dbms_stats.gather_table_stats(user,'zzh_ob',cascade=>true);

原sql执行计划:

SQL> set autot trace explain

SQL> select * from zzh_ob where object_id=16;

Execution Plan

Plan hash value: 3485916696

| 0 | SELECT STATEMENT | | 1 | 127 | 2 (0)| 00:00:01 |

| 1 | TABLE ACCESS BY INDEX ROWID BATCHED| ZZH_OB | 1 | 127 | 2 (0)| 00:00:01 |

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

Predicate Information (identified by operation id):

2 - access("OBJECT_ID"=16)

新sql执行计划

SQL> select /*+ full(zzh_ob) */ * from zzh_ob where object_id=16;

Execution Plan

Plan hash value: 474274488

| 0 | SELECT STATEMENT | | 1 | 127 | 388 (1)| 00:00:01 |

|* 1 | TABLE ACCESS FULL| ZZH_OB | 1 | 127 | 388 (1)| 00:00:01 |

Predicate Information (identified by operation id):

1 - filter("OBJECT_ID"=16)

2、获取新sql的sql_id

SQL> col sql_id for a20

SQL> col sql_text for a120

SQL> select sql_id,sql_text from v$sql where sql_text like '%full(zzh_ob)%';

SQL_ID SQL_TEXT

g5btxvsh51ct5 EXPLAIN PLAN SET STATEMENT_ID='PLUS1200001' FOR select sql_id,sql_text from v$sql where sql_text like '%full(zzh_ob)%'

4kn9w9q3xf73k EXPLAIN PLAN SET STATEMENT_ID='PLUS1200001' FOR select /*+ full(zzh_ob) */ * from zzh_ob where object_id=16

68x7hd7uaqqk1 select sql_id,sql_text from v$sql where sql_text like '%full(zzh_ob)%'

1syfgv2q5ggn2 select /*+ full(zzh_ob) */ * from zzh_ob where object_id=16

3、获取新sql的outline

SQL> set pagesize 1000

SQL> select * from table(dbms_xplan.display_cursor('1syfgv2q5ggn2',null,'outline'));

PLAN_TABLE_OUTPUT

SQL_ID 1syfgv2q5ggn2, child number 0

select /*+ full(zzh_ob) */ * from zzh_ob where object_id=16

Plan hash value: 474274488

| 0 | SELECT STATEMENT | | | | 388 (100)| |

|* 1 | TABLE ACCESS FULL| ZZH_OB | 1 | 127 | 388 (1)| 00:00:01 |

PLAN_TABLE_OUTPUT

Outline Data

/*+

BEGIN_OUTLINE_DATA

IGNORE_OPTIM_EMBEDDED_HINTS

OPTIMIZER_FEATURES_ENABLE('19.1.0')

DB_VERSION('19.1.0')

ALL_ROWS

PLAN_TABLE_OUTPUT

OUTLINE_LEAF(@"SEL$1")

FULL(@"SEL $1" ["ZZH_OB"@"SEL$ 1](mailto:)")

END_OUTLINE_DATA

Predicate Information (identified by operation id):

1 - filter("OBJECT_ID"=16)

32 rows selected.

4、创建sql profile(SQLPROFILE_01)

SQL> declare

v_hints sys.sqlprof_attr;

begin

v_hints:=sys.sqlprof_attr(

'BEGIN_OUTLINE_DATA',

'IGNORE_OPTIM_EMBEDDED_HINTS',

'OPTIMIZER_FEATURES_ENABLE(''19.1.0'')',

'DB_VERSION(''19.1.0'')',

'ALL_ROWS',

'OUTLINE_LEAF(@"SEL$1")',

'FULL(@"SEL $1" ["ZZH_OB"@"SEL$ 1")'](mailto:),

'END_OUTLINE_DATA');

dbms_sqltune.import_sql_profile(

'select * from zzh_ob where object_id=16',

v_hints,'SQLPROFILE_01',

force_match=>true,replace=>false);

end;

5、查看是否使用 sql profile

SQL> set autot trace explain

SQL> select * from zzh_ob where object_id=16;

Execution Plan

Plan hash value: 474274488

| 0 | SELECT STATEMENT | | 1 | 127 | 388 (1)| 00:00:01 |

|* 1 | TABLE ACCESS FULL| ZZH_OB | 1 | 127 | 388 (1)| 00:00:01 |

Predicate Information (identified by operation id):

1 - filter("OBJECT_ID"=16)

Note

SQL profile "SQLPROFILE_01" used for this statement

Statistics

247 recursive calls

0 db block gets

1544 consistent gets

2 physical reads

0 redo size

2685 bytes sent via SQL*Net to client

401 bytes received via SQL*Net from client

2 SQL*Net roundtrips to/from client

11 sorts (memory)

0 sorts (disk)

1 rows processed

查询已经创建的 sql profile ：

SELECT name, created, category, sql_Text from dba_sql_profiles ORDER BY created DESC;