近期，在优化一个SQL时用到了QB_NAME的HINT，此HINT我经常使用的原因目的是让子查询单独作为一个整体，与其他表关联时可以进行调整驱动顺序，举例：

SELECT b.owner,
       b.object_name,
       b.created,
       b.status
FROM albert.fc b
WHERE 1=1
  AND b.object_id IN
    (SELECT c.object_id
     FROM albert.P c
     WHERE c.owner='NFS_SN')
执行计划如下：
Plan hash value: 3977992979

--------------------------------------------------------------------------------------------------------------------------
| Id  | Operation		     | Name    | Starts | E-Rows | Cost (%CPU)| E-Time	 | A-Rows |   A-Time   | Buffers |
--------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT	     |	       |      1 |	 |   569 (100)| 	 |    119 |00:00:00.05 |    1445 |
|*  1 |  HASH JOIN RIGHT SEMI	     |	       |      1 |  64830 |   569  (11)| 00:00:07 |    119 |00:00:00.05 |    1445 |
|   2 |   TABLE ACCESS BY INDEX ROWID| P       |      1 |   2192 |   116   (0)| 00:00:02 |    119 |00:00:00.01 |      17 |
|*  3 |    INDEX RANGE SCAN	     | P_IDX01 |      1 |   2192 |     6   (0)| 00:00:01 |    119 |00:00:00.01 |       2 |
|   4 |   TABLE ACCESS FULL	     | FC      |      1 |   3000K|   439  (11)| 00:00:06 |    100K|00:00:00.02 |    1428 |
--------------------------------------------------------------------------------------------------------------------------

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

   1 - SEL$5DA710D3
   2 - SEL$5DA710D3 / C@SEL$2
   3 - SEL$5DA710D3 / C@SEL$2
   4 - SEL$5DA710D3 / B@SEL$1

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

  /*+
      BEGIN_OUTLINE_DATA
      IGNORE_OPTIM_EMBEDDED_HINTS
      OPTIMIZER_FEATURES_ENABLE('11.2.0.4')
      DB_VERSION('11.2.0.4')
      OPT_PARAM('_optim_peek_user_binds' 'false')
      OPT_PARAM('_optimizer_use_feedback' 'false')
      ALL_ROWS
      OUTLINE_LEAF(@"SEL$5DA710D3")
      UNNEST(@"SEL$2")
      OUTLINE(@"SEL$1")
      OUTLINE(@"SEL$2")
      FULL(@"SEL$5DA710D3" "B"@"SEL$1")
      INDEX_RS_ASC(@"SEL$5DA710D3" "C"@"SEL$2" ("P"."OWNER"))
      LEADING(@"SEL$5DA710D3" "B"@"SEL$1" "C"@"SEL$2")
      USE_HASH(@"SEL$5DA710D3" "C"@"SEL$2")
      SWAP_JOIN_INPUTS(@"SEL$5DA710D3" "C"@"SEL$2")
      END_OUTLINE_DATA
  */

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

   1 - access("B"."OBJECT_ID"="C"."OBJECT_ID")
   3 - access("C"."OWNER"='NFS_SN')