PUSH_PRED HINT

1.未加hint前

SQL> EXPLAIN PLAN FOR

  2  SELECT  C.CORRESPONDORGID ORGID,
  3         A.TYPENAME,
  4         B.PORTCODE        RMNAME,
  5         B.PORTCODE        RMENTITYCODE,
  6         A.OCFCODE         RMOWNENTITYCODE
  7    FROM V_OCF_FAC A, OPT_OCFPORT B, BAS_STATION C
  8   WHERE A.OCFID = B.OCFID
  9     AND A.STATIONID = C.FACID
 10     AND B.PORTID = 1950004541119;

Explained.

SQL> SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY);

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 655622816

------------------------------------------------------------------------------------------------
| Id  | Operation                     | Name           | Rows  | Bytes | Cost (%CPU)| Time     |
------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT              |                |     5 |  1005 |   368   (2)| 00:00:04 |
|   1 |  NESTED LOOPS                 |                |     5 |  1005 |   368   (2)| 00:00:04 |
|   2 |   NESTED LOOPS                |                |     5 |   945 |   363   (2)| 00:00:04 |
|   3 |    TABLE ACCESS BY INDEX ROWID| OPT_OCFPORT    |     1 |    26 |     3   (0)| 00:00:01 |
|*  4 |     INDEX UNIQUE SCAN         | PK_OPT_OCFPORT |     1 |       |     2   (0)| 00:00:01 |
|*  5 |    VIEW                       | V_OCF_FAC      |     5 |   815 |   360   (2)| 00:00:04 |

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------
|   6 |     UNION-ALL                 |                |       |       |            |          |
|   7 |      TABLE ACCESS FULL        | OPT_OCF        | 25992 |  1319K|   331   (2)| 00:00:04 |
|   8 |      TABLE ACCESS FULL        | CAB_CCF        |   739 | 29560 |     8   (0)| 00:00:01 |
|   9 |      TABLE ACCESS FULL        | OPT_JOINT      |  3768 |   154K|    21   (0)| 00:00:01 |
|  10 |   TABLE ACCESS BY INDEX ROWID | BAS_STATION    |     1 |    12 |     1   (0)| 00:00:01 |
|* 11 |    INDEX UNIQUE SCAN          | PK_BAS_STATION |     1 |       |     0   (0)| 00:00:01 |
------------------------------------------------------------------------------------------------

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


PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------
   4 - access("B"."PORTID"=1950004541119)
   5 - filter("A"."OCFID"="B"."OCFID")
  11 - access("A"."STATIONID"="C"."FACID")

Note
-----
   - 'PLAN_TABLE' is old version

29 rows selected.

2.加了hint后

**********************************************************************************************************************

SQL> explain plan for
  2  SELECT /*+ PUSH_PRED(A) */ C.CORRESPONDORGID ORGID,
  3         A.TYPENAME,
  4         B.PORTCODE        RMNAME,
  5         B.PORTCODE        RMENTITYCODE,
  6         A.OCFCODE         RMOWNENTITYCODE
  7    FROM V_OCF_FAC A, OPT_OCFPORT B, BAS_STATION C
  8   WHERE A.OCFID = B.OCFID
  9     AND A.STATIONID = C.FACID
 10     AND B.PORTID = 1950004541119;

Explained.

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

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 3253457126

-------------------------------------------------------------------------------------------------
| Id  | Operation                      | Name           | Rows  | Bytes | Cost (%CPU)| Time     |
-------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT               |                |     5 |  1065 | 16281   (1)| 00:02:30 |
|   1 |  NESTED LOOPS                  |                |     5 |  1065 | 16281   (1)| 00:02:30 |
|   2 |   NESTED LOOPS                 |                |  2708 |   148K|    19   (0)| 00:00:01 |
|   3 |    TABLE ACCESS BY INDEX ROWID | OPT_OCFPORT    |     1 |    35 |     3   (0)| 00:00:01 |
|*  4 |     INDEX UNIQUE SCAN          | PK_OPT_OCFPORT |     1 |       |     2   (0)| 00:00:01 |
|   5 |    TABLE ACCESS FULL           | BAS_STATION    |  2708 | 56868 |    16   (0)| 00:00:01 |

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------
|   6 |   VIEW                         | V_OCF_FAC      |     1 |   157 |     6   (0)| 00:00:01 |
|   7 |    UNION ALL PUSHED PREDICATE  |                |       |       |            |          |
|*  8 |     TABLE ACCESS BY INDEX ROWID| OPT_OCF        |     1 |    52 |     2   (0)| 00:00:01 |
|*  9 |      INDEX UNIQUE SCAN         | PK_OPT_OCF     |     1 |       |     1   (0)| 00:00:01 |
|* 10 |     TABLE ACCESS BY INDEX ROWID| CAB_CCF        |     1 |    40 |     2   (0)| 00:00:01 |
|* 11 |      INDEX UNIQUE SCAN         | PK_CAB_CCF     |     1 |       |     1   (0)| 00:00:01 |
|* 12 |     TABLE ACCESS BY INDEX ROWID| OPT_JOINT      |     1 |    42 |     2   (0)| 00:00:01 |
|* 13 |      INDEX UNIQUE SCAN         | PK_OPT_JOINT   |     1 |       |     1   (0)| 00:00:01 |
-------------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------
---------------------------------------------------

   4 - access("B"."PORTID"=1950004541119)
   8 - filter("T"."STATIONID"="C"."FACID")
   9 - access("T"."OCFID"="B"."OCFID")
  10 - filter("C"."STATIONID"="C"."FACID")
  11 - access("C"."CCFID"="B"."OCFID")
  12 - filter("T"."STATIONID"="C"."FACID")
  13 - access("T"."JOINTID"="B"."OCFID")