oracle hint inline materialize

当我们使用with的时候，oracle可能会把with里面的结果转换为暂时表。这是仅仅是可能，由于CBO会推断。

inline是不转换成暂时表。materialize是强制转换成暂时表。

制造数据

drop table test1 purge;

drop table test2 purge;

drop table test3 purge;

create table test1 as  select * from dba_objects;

create table test2 as  select * from user_objects;

create table test3 as  select * from dba_objects;

exec dbms_stats.gather_table_stats(user,'test1');

exec dbms_stats.gather_table_stats(user,'test2');

exec dbms_stats.gather_table_stats(user,'test3');

SQL> select * from v$version;

BANNER

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

Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production

PL/SQL Release 11.2.0.1.0 - Production

CORE    11.2.0.1.0      Production

TNS for Linux: Version 11.2.0.1.0 - Production

NLSRTL Version 11.2.0.1.0 - Production

SQL> set autotrace traceonly

SQL> with t as(select t1.* from test1 t1,test2 t2

       where t1.object_id=t2.object_id)

    select * from t,test3 t3 where t.object_id=t3.object_id;

已选择1931行。

已用时间:  00: 00: 00.20

运行计划

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

Plan hash value: 1215971386

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

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

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

|   0 | SELECT STATEMENT    |       |  1931 |   382K|   409   (2)| 00:00:06 |

|*  1 |  HASH JOIN          |       |  1931 |   382K|   409   (2)| 00:00:06 |

|*  2 |   HASH JOIN         |       |  1932 |   196K|   210   (2)| 00:00:03 |

|   3 |    TABLE ACCESS FULL| TEST2 |  1934 |  9670 |    10   (0)| 00:00:01 |

|   4 |    TABLE ACCESS FULL| TEST1 | 71347 |  6897K|   199   (2)| 00:00:03 |

|   5 |   TABLE ACCESS FULL | TEST3 | 71349 |  6897K|   199   (2)| 00:00:03 |

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

Predicate Information (identified by operation id):

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

   1 - access("T1"."OBJECT_ID"="T3"."OBJECT_ID")

   2 - access("T1"."OBJECT_ID"="T2"."OBJECT_ID")

统计信息

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

          1  recursive calls

          0  db block gets

       1173  consistent gets

          0  physical reads

          0  redo size

     139087  bytes sent via SQL*Net to client

       1768  bytes received via SQL*Net from client

        130  SQL*Net roundtrips to/from client

          0  sorts (memory)

          0  sorts (disk)

       1931  rows processed

使用hint inline

SQL> with t as(select /*+inline*/t1.* from test1 t1,test2 t2

       where t1.object_id=t2.object_id)

    select * from t,test3 t3 where t.object_id=t3.object_id;

已选择1931行。

已用时间:  00: 00: 00.21

运行计划

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

Plan hash value: 1215971386

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

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

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

|   0 | SELECT STATEMENT    |       |  1931 |   382K|   409   (2)| 00:00:06 |

|*  1 |  HASH JOIN          |       |  1931 |   382K|   409   (2)| 00:00:06 |

|*  2 |   HASH JOIN         |       |  1932 |   196K|   210   (2)| 00:00:03 |

|   3 |    TABLE ACCESS FULL| TEST2 |  1934 |  9670 |    10   (0)| 00:00:01 |

|   4 |    TABLE ACCESS FULL| TEST1 | 71347 |  6897K|   199   (2)| 00:00:03 |

|   5 |   TABLE ACCESS FULL | TEST3 | 71349 |  6897K|   199   (2)| 00:00:03 |

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

Predicate Information (identified by operation id):

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

   1 - access("T1"."OBJECT_ID"="T3"."OBJECT_ID")

   2 - access("T1"."OBJECT_ID"="T2"."OBJECT_ID")

统计信息

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

          1  recursive calls

          0  db block gets

       1173  consistent gets

          0  physical reads

          0  redo size

     139087  bytes sent via SQL*Net to client

       1768  bytes received via SQL*Net from client

        130  SQL*Net roundtrips to/from client

          0  sorts (memory)

          0  sorts (disk)

       1931  rows processed

使用hint materialize

SQL> with t as(select /*+materialize*/t1.* from test1 t1,test2 t2

       where t1.object_id=t2.object_id)

    select * from t,test3 t3 where t.object_id=t3.object_id;

已选择1931行。

已用时间:  00: 00: 00.21

运行计划

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

Plan hash value: 1492452360

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

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

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

|   0 | SELECT STATEMENT           |                             |  1925 |   575K|   416   (2)| 00:00:06 |

|   1 |  TEMP TABLE TRANSFORMATION |                             |       |       |            |       |

|   2 |   LOAD AS SELECT           | SYS_TEMP_0FD9D660C_9A3A2AEA |       |       |            |       |

|*  3 |    HASH JOIN               |                             |  1932 |   196K|   210   (2)| 00:00:03 |

|   4 |     TABLE ACCESS FULL      | TEST2                       |  1934 |  9670 |    10   (0)| 00:00:01 |

|   5 |     TABLE ACCESS FULL      | TEST1                       | 71347 |  6897K|   199   (2)| 00:00:03 |

|*  6 |   HASH JOIN                |                             |  1925 |   575K|   207   (2)| 00:00:03 |

|   7 |    VIEW                    |                             |  1932 |   390K|     7   (0)| 00:00:01 |

|   8 |     TABLE ACCESS FULL      | SYS_TEMP_0FD9D660C_9A3A2AEA |  1932 |   196K|     7   (0)| 00:00:01 |

|   9 |    TABLE ACCESS FULL       | TEST3                       | 71349 |  6897K|   199   (2)| 00:00:03 |

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

Predicate Information (identified by operation id):

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

   3 - access("T1"."OBJECT_ID"="T2"."OBJECT_ID")

   6 - access("T"."OBJECT_ID"="T3"."OBJECT_ID")

统计信息

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

        394  recursive calls

         25  db block gets

       1243  consistent gets

         18  physical reads

        600  redo size

     139087  bytes sent via SQL*Net to client

       1768  bytes received via SQL*Net from client

        130  SQL*Net roundtrips to/from client

          0  sorts (memory)

          0  sorts (disk)

       1931  rows processed