执行计划杂记

在oracle 11g中，dbms_xplan包已经增加了不少内容，不再像9i一般只局限于display。在这里小记一把和执行计划相关的内容。

(1) gather_plan_statistics 和dbms_xplan.display_cursor连用，如：

sys@ORA10G(9.115.110.142)> set SERVEROUT off
sys@ORA10G(9.115.110.142)>
sys@ORA10G(9.115.110.142)>
sys@ORA10G(9.115.110.142)>
sys@ORA10G(9.115.110.142)> select  /*+ gather_plan_statistics */ count(*) from dual;

  COUNT(*)
----------
         1

Elapsed: 00:00:00.00
sys@ORA10G(9.115.110.142)> select* from table(dbms_xplan.display_cursor(null,null,'ALLSTATS LAST'));

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------------------
SQL_ID  0cb33av5khrss, child number 0
-------------------------------------
select  /*+ gather_plan_statistics */ count(*) from dual

Plan hash value: 3910148636

-----------------------------------------------------------------------
| Id  | Operation      | Name | Starts | E-Rows | A-Rows |   A-Time   |
-----------------------------------------------------------------------
|   1 |  SORT AGGREGATE|      |      1 |      1 |      1 |00:00:00.01 |
|   2 |   FAST DUAL    |      |      1 |      1 |      1 |00:00:00.01 |
-----------------------------------------------------------------------


13 rows selected.

Elapsed: 00:00:00.96
sys@ORA10G(9.115.110.142)>

sys@ORA10G(9.115.110.142)> set SERVEROUT off

sys@ORA10G(9.115.110.142)>

sys@ORA10G(9.115.110.142)> select /*+ gather_plan_statistics */ count(*) from dual;

COUNT(*)

----------

Elapsed: 00:00:00.00

sys@ORA10G(9.115.110.142)> select* from table(dbms_xplan.display_cursor(null,null,'ALLSTATS LAST'));

PLAN_TABLE_OUTPUT

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

SQL_ID 0cb33av5khrss, child number 0

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

select /*+ gather_plan_statistics */ count(*) from dual

Plan hash value: 3910148636

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

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

| 1 | SORT AGGREGATE| | 1 | 1 | 1 |00:00:00.01 |

| 2 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 |

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

13 rows selected.

Elapsed: 00:00:00.96

sys@ORA10G(9.115.110.142)>

在此处看 E-Rows和A-Rows之间的差别是否巨大，如差距大则表示estimate rows和actual rows之间差距巨大，统计信息可能有问题。

(2) 看历史的执行计划：
历史的执行计划可以在dba_hist_sql_plan中找到，有不同的PLAN_HASH_VALUE，并且我们可以结合awr来一起看。

SQL> l
  1  select DBID,SQL_ID,PLAN_HASH_VALUE,to_char(TIMESTAMP,'yyyy-mm-dd hh24:mi:ss') TIMESTAMP from dba_hist_sql_plan
  2  where SQL_ID='frgzxkprkwntn'
  3  group by DBID,SQL_ID,PLAN_HASH_VALUE,to_char(TIMESTAMP,'yyyy-mm-dd hh24:mi:ss')
  4* order by TIMESTAMP
SQL> /

      DBID SQL_ID               PLAN_HASH_VALUE TIMESTAMP
---------- -------------------- --------------- -------------------
2694280230 frgzxkprkwntn              996644735 2012-06-15 01:06:53
2694280230 frgzxkprkwntn              883847748 2012-07-02 12:28:15
2694280230 frgzxkprkwntn             1190191859 2012-07-03 08:50:37
2694280230 frgzxkprkwntn             3418420592 2012-07-09 07:48:51
2694280230 frgzxkprkwntn             3487426888 2012-07-16 12:07:12

SQL> 
我们看到一个sql id为'frgzxkprkwntn'有5个历史版本的执行计划。我们可以利用dbms_xplan.display_awr(sql_id,plan_hash_value,dbid,FORMAT)来看，如果FORMAT为'peeked_binds'甚至可以看当时绑定的变量：

SQL> select * from table(dbms_xplan.DISPLAY_AWR('frgzxkprkwntn','996644735','2694280230','peeked_binds'));

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SQL_ID frgzxkprkwntn
--------------------
SELECT COUNT(TBTC.REQUEST_OBJECT_ID) FROM TBTC_REQUEST TBTC,
TBLK_REQUEST_TX TBLK WHERE TBTC.REQUEST_TYPE_CODE = :B4 AND
TBTC.DIRECTION = :B3 AND TBTC.REQUEST_STATUS_CODE = :B2 AND
TBLK.REQUEST_OBJECT_ID = TBTC.REQUEST_OBJECT_ID AND
TBLK.REQUEST_TX_TYPE_CODE = :B1 AND EXISTS ( SELECT NULL FROM
MYTB_TX_HELPM_ENTRY MYTB, TB09_TX_ACTIVITY TB09 WHERE
(TBLK.REQUEST_TX_OBJECT_ID = MYTB.REQUEST_TX_OBJECT_ID AND
MYTB.REQUEST_TX_OBJECT_ID = TB09.REQUEST_TX_OBJECT_ID) AND
MYTB.TX_HELPM_ENTRY_TYPE_CODE = :B9 AND MYTB.HELPM_TS > :B8 AND
MYTB.HELPM_TS < :B7 AND MYTB.REQUEST_TX_OBJECT_ID =
TBLK.REQUEST_TX_OBJECT_ID AND TB09.ACTIVITY_ID = :B6 AND
TB09.TX_ACTIVITY_STATUS_CODE = :B5 AND NOT EXISTS ( SELECT NULL FROM
MYTB_TX_HELPM_ENTRY B WHERE B.REQUEST_TX_OBJECT_ID =
MYTB.REQUEST_TX_OBJECT_ID AND B.HELPM_CARRIER_ID =
MYTB.HELPM_CARRIER_ID AND (B.TX_HELPM_ENTRY_TYPE_CODE = :B11 OR
B.TX_HELPM_ENTRY_TYPE_CODE = :B10 ) ) )

Plan hash value: 996644735

-----------------------------------------------------------------------------------------------------------------
| Id  | Operation                         | Name                        | Rows  | Bytes | Cost (%CPU)| Time     |
-----------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                  |                             |       |       |   419 (100)|          |
|   1 |  SORT AGGREGATE                   |                             |     1 |    44 |            |          |
|   2 |   FILTER                          |                             |       |       |            |          |
|   3 |    NESTED LOOPS                   |                             |       |       |            |          |
|   4 |     NESTED LOOPS                  |                             |    59 |  2596 |   124   (0)| 00:00:02 |
|   5 |      TABLE ACCESS BY INDEX ROWID  | TBTC_REQUEST                |    50 |  1250 |    23   (0)| 00:00:01 |
|   6 |       INDEX RANGE SCAN            | TBTC_I_STATUS_REQ_OBJ_ID    |   317 |       |     5   (0)| 00:00:01 |
|   7 |      INDEX RANGE SCAN             | TBLK_I_REQ_OBJ_ID           |     2 |       |     2   (0)| 00:00:01 |
|   8 |     TABLE ACCESS BY INDEX ROWID   | TBLK_REQUEST_TX             |     1 |    19 |     3   (0)| 00:00:01 |
|   9 |    FILTER                         |                             |       |       |            |          |
|  10 |     NESTED LOOPS                  |                             |       |       |            |          |
|  11 |      NESTED LOOPS                 |                             |     1 |    68 |    10   (0)| 00:00:01 |
|  12 |       NESTED LOOPS ANTI           |                             |     1 |    48 |     7   (0)| 00:00:01 |
|  13 |        TABLE ACCESS BY INDEX ROWID| MYTB_TX_HELPM_ENTRY         |     1 |    28 |     4   (0)| 00:00:01 |
|  14 |         INDEX RANGE SCAN          | MYTB_C_PK                   |     1 |       |     3   (0)| 00:00:01 |
|  15 |        INLIST ITERATOR            |                             |       |       |            |          |
|  16 |         INDEX UNIQUE SCAN         | MYTB_C_PK                   |     1 |    20 |     3   (0)| 00:00:01 |
|  17 |       INDEX RANGE SCAN            | TB09_I_REQUEST_TX_OBJECT_ID |     1 |       |     2   (0)| 00:00:01 |
|  18 |      TABLE ACCESS BY INDEX ROWID  | TB09_TX_ACTIVITY            |     1 |    20 |     3   (0)| 00:00:01 |
-----------------------------------------------------------------------------------------------------------------

Peeked Binds (identified by position):
--------------------------------------

   1 - :B4 (VARCHAR2(30), CSID=1): 'PORT'
   2 - :B3 (VARCHAR2(30), CSID=1): 'O'
   3 - :B2 (VARCHAR2(30), CSID=1): 'CTVR CNFM'
   4 - :B1 (VARCHAR2(30), CSID=1): 'BPCN'
   5 - :B9 (VARCHAR2(30), CSID=1): 'RECEIVED'
   6 - :B8 (DATE): 06/04/2012 00:00:00
   7 - :B7 (DATE): 06/14/2012 23:59:59
   8 - :B6 (NUMBER): 9
   9 - :B5 (VARCHAR2(30), CSID=1): 'OPEN'
  10 - :B11 (VARCHAR2(30), CSID=1): 'CONFIRMED'
  11 - :B10 (VARCHAR2(30), CSID=1): 'REJECTED'


60 rows selected.

SQL> 
SQL> select * from table(dbms_xplan.DISPLAY_AWR('frgzxkprkwntn','3487426888','2694280230','peeked_binds'));

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SQL_ID frgzxkprkwntn
--------------------
SELECT COUNT(TBTC.REQUEST_OBJECT_ID) FROM TBTC_REQUEST TBTC,
TBLK_REQUEST_TX TBLK WHERE TBTC.REQUEST_TYPE_CODE = :B4 AND
TBTC.DIRECTION = :B3 AND TBTC.REQUEST_STATUS_CODE = :B2 AND
TBLK.REQUEST_OBJECT_ID = TBTC.REQUEST_OBJECT_ID AND
TBLK.REQUEST_TX_TYPE_CODE = :B1 AND EXISTS ( SELECT NULL FROM
MYTB_TX_HELPM_ENTRY MYTB, TB09_TX_ACTIVITY TB09 WHERE
(TBLK.REQUEST_TX_OBJECT_ID = MYTB.REQUEST_TX_OBJECT_ID AND
MYTB.REQUEST_TX_OBJECT_ID = TB09.REQUEST_TX_OBJECT_ID) AND
MYTB.TX_HELPM_ENTRY_TYPE_CODE = :B9 AND MYTB.HELPM_TS > :B8 AND
MYTB.HELPM_TS < :B7 AND MYTB.REQUEST_TX_OBJECT_ID =
TBLK.REQUEST_TX_OBJECT_ID AND TB09.ACTIVITY_ID = :B6 AND
TB09.TX_ACTIVITY_STATUS_CODE = :B5 AND NOT EXISTS ( SELECT NULL FROM
MYTB_TX_HELPM_ENTRY B WHERE B.REQUEST_TX_OBJECT_ID =
MYTB.REQUEST_TX_OBJECT_ID AND B.HELPM_CARRIER_ID =
MYTB.HELPM_CARRIER_ID AND (B.TX_HELPM_ENTRY_TYPE_CODE = :B11 OR
B.TX_HELPM_ENTRY_TYPE_CODE = :B10 ) ) )

Plan hash value: 3487426888

---------------------------------------------------------------------------------------------------------------------
| Id  | Operation                             | Name                        | Rows  | Bytes | Cost (%CPU)| Time     |
---------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                      |                             |       |       |     8 (100)|          |
|   1 |  SORT AGGREGATE                       |                             |     1 |    57 |            |          |
|   2 |   NESTED LOOPS                        |                             |       |       |            |          |
|   3 |    NESTED LOOPS                       |                             |     1 |    57 |     8  (13)| 00:00:01 |
|   4 |     NESTED LOOPS                      |                             |     1 |    32 |     7  (15)| 00:00:01 |
|   5 |      VIEW                             | VW_SQ_1                     |     1 |    13 |     5   (0)| 00:00:01 |
|   6 |       HASH UNIQUE                     |                             |     1 |    68 |            |          |
|   7 |        FILTER                         |                             |       |       |            |          |
|   8 |         NESTED LOOPS                  |                             |       |       |            |          |
|   9 |          NESTED LOOPS                 |                             |     1 |    68 |     5   (0)| 00:00:01 |
|  10 |           NESTED LOOPS ANTI           |                             |     1 |    48 |     4   (0)| 00:00:01 |
|  11 |            TABLE ACCESS BY INDEX ROWID| MYTB_TX_HELPM_ENTRY         |     1 |    28 |     4   (0)| 00:00:01 |
|  12 |             INDEX RANGE SCAN          | MYTB_I_HELPM_TS_TXOBJ       |     1 |       |     3   (0)| 00:00:01 |
|  13 |            INLIST ITERATOR            |                             |       |       |            |          |
|  14 |             INDEX UNIQUE SCAN         | MYTB_C_PK                   |  1102K|    21M|     0   (0)|          |
|  15 |           INDEX RANGE SCAN            | TB09_I_REQUEST_TX_OBJECT_ID |     3 |       |     0   (0)|          |
|  16 |          TABLE ACCESS BY INDEX ROWID  | TB09_TX_ACTIVITY            |     1 |    20 |     1   (0)| 00:00:01 |
|  17 |      TABLE ACCESS BY INDEX ROWID      | TBLK_REQUEST_TX             |     1 |    19 |     1   (0)| 00:00:01 |
|  18 |       INDEX UNIQUE SCAN               | TBLK_C_PK                   |     1 |       |     0   (0)|          |
|  19 |     INDEX RANGE SCAN                  | TBTC_I_STATUS_REQ_OBJ_ID    |     1 |       |     0   (0)|          |
|  20 |    TABLE ACCESS BY INDEX ROWID        | TBTC_REQUEST                |     1 |    25 |     1   (0)| 00:00:01 |
---------------------------------------------------------------------------------------------------------------------

Peeked Binds (identified by position):
--------------------------------------

   1 - :B4 (VARCHAR2(30), CSID=1): 'PORT'
   2 - :B3 (VARCHAR2(30), CSID=1): 'O'
   3 - :B2 (VARCHAR2(30), CSID=1): 'CTVR CNFM'
   4 - :B1 (VARCHAR2(30), CSID=1): 'BPCN'
   5 - :B9 (VARCHAR2(30), CSID=1): 'RECEIVED'
   6 - :B8 (DATE): 07/16/2012 00:00:00
   7 - :B7 (DATE): 07/16/2012 11:52:12
   8 - :B6 (NUMBER): 9
   9 - :B5 (VARCHAR2(30), CSID=1): 'OPEN'
  10 - :B11 (VARCHAR2(30), CSID=1): 'CONFIRMED'
  11 - :B10 (VARCHAR2(30), CSID=1): 'REJECTED'


62 rows selected.

SQL>

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SQL> l

1 select DBID,SQL_ID,PLAN_HASH_VALUE,to_char(TIMESTAMP,'yyyy-mm-dd hh24:mi:ss') TIMESTAMP from dba_hist_sql_plan

2 where SQL_ID='frgzxkprkwntn'

3 group by DBID,SQL_ID,PLAN_HASH_VALUE,to_char(TIMESTAMP,'yyyy-mm-dd hh24:mi:ss')

4* order by TIMESTAMP

SQL> /

DBID SQL_ID PLAN_HASH_VALUE TIMESTAMP

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

2694280230 frgzxkprkwntn 996644735 2012-06-15 01:06:53

2694280230 frgzxkprkwntn 883847748 2012-07-02 12:28:15

2694280230 frgzxkprkwntn 1190191859 2012-07-03 08:50:37

2694280230 frgzxkprkwntn 3418420592 2012-07-09 07:48:51

2694280230 frgzxkprkwntn 3487426888 2012-07-16 12:07:12

SQL>

我们看到一个sql id为'frgzxkprkwntn'有5个历史版本的执行计划。我们可以利用dbms_xplan.display_awr(sql_id,plan_hash_value,dbid,FORMAT)来看，如果FORMAT为'peeked_binds'甚至可以看当时绑定的变量：

SQL> select * from table(dbms_xplan.DISPLAY_AWR('frgzxkprkwntn','996644735','2694280230','peeked_binds'));

PLAN_TABLE_OUTPUT

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

SQL_ID frgzxkprkwntn

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

SELECT COUNT(TBTC.REQUEST_OBJECT_ID) FROM TBTC_REQUEST TBTC,

TBLK_REQUEST_TX TBLK WHERE TBTC.REQUEST_TYPE_CODE = :B4 AND

TBTC.DIRECTION = :B3 AND TBTC.REQUEST_STATUS_CODE = :B2 AND

TBLK.REQUEST_OBJECT_ID = TBTC.REQUEST_OBJECT_ID AND

TBLK.REQUEST_TX_TYPE_CODE = :B1 AND EXISTS ( SELECT NULL FROM

MYTB_TX_HELPM_ENTRY MYTB, TB09_TX_ACTIVITY TB09 WHERE

(TBLK.REQUEST_TX_OBJECT_ID = MYTB.REQUEST_TX_OBJECT_ID AND

MYTB.REQUEST_TX_OBJECT_ID = TB09.REQUEST_TX_OBJECT_ID) AND

MYTB.TX_HELPM_ENTRY_TYPE_CODE = :B9 AND MYTB.HELPM_TS > :B8 AND

MYTB.HELPM_TS < :B7 AND MYTB.REQUEST_TX_OBJECT_ID =

TBLK.REQUEST_TX_OBJECT_ID AND TB09.ACTIVITY_ID = :B6 AND

TB09.TX_ACTIVITY_STATUS_CODE = :B5 AND NOT EXISTS ( SELECT NULL FROM

MYTB_TX_HELPM_ENTRY B WHERE B.REQUEST_TX_OBJECT_ID =

MYTB.REQUEST_TX_OBJECT_ID AND B.HELPM_CARRIER_ID =

MYTB.HELPM_CARRIER_ID AND (B.TX_HELPM_ENTRY_TYPE_CODE = :B11 OR

B.TX_HELPM_ENTRY_TYPE_CODE = :B10 ) ) )

Plan hash value: 996644735

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

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

| 0 | SELECT STATEMENT | | | | 419 (100)| |

| 1 | SORT AGGREGATE | | 1 | 44 | | |

| 2 | FILTER | | | | | |

| 3 | NESTED LOOPS | | | | | |

| 4 | NESTED LOOPS | | 59 | 2596 | 124 (0)| 00:00:02 |

| 5 | TABLE ACCESS BY INDEX ROWID | TBTC_REQUEST | 50 | 1250 | 23 (0)| 00:00:01 |

| 6 | INDEX RANGE SCAN | TBTC_I_STATUS_REQ_OBJ_ID | 317 | | 5 (0)| 00:00:01 |

| 7 | INDEX RANGE SCAN | TBLK_I_REQ_OBJ_ID | 2 | | 2 (0)| 00:00:01 |

| 8 | TABLE ACCESS BY INDEX ROWID | TBLK_REQUEST_TX | 1 | 19 | 3 (0)| 00:00:01 |

| 9 | FILTER | | | | | |

| 10 | NESTED LOOPS | | | | | |

| 11 | NESTED LOOPS | | 1 | 68 | 10 (0)| 00:00:01 |

| 12 | NESTED LOOPS ANTI | | 1 | 48 | 7 (0)| 00:00:01 |

| 13 | TABLE ACCESS BY INDEX ROWID| MYTB_TX_HELPM_ENTRY | 1 | 28 | 4 (0)| 00:00:01 |

| 14 | INDEX RANGE SCAN | MYTB_C_PK | 1 | | 3 (0)| 00:00:01 |

| 15 | INLIST ITERATOR | | | | | |

| 16 | INDEX UNIQUE SCAN | MYTB_C_PK | 1 | 20 | 3 (0)| 00:00:01 |

| 17 | INDEX RANGE SCAN | TB09_I_REQUEST_TX_OBJECT_ID | 1 | | 2 (0)| 00:00:01 |

| 18 | TABLE ACCESS BY INDEX ROWID | TB09_TX_ACTIVITY | 1 | 20 | 3 (0)| 00:00:01 |

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

Peeked Binds (identified by position):

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

1 - :B4 (VARCHAR2(30), CSID=1): 'PORT'

2 - :B3 (VARCHAR2(30), CSID=1): 'O'

3 - :B2 (VARCHAR2(30), CSID=1): 'CTVR CNFM'

4 - :B1 (VARCHAR2(30), CSID=1): 'BPCN'

5 - :B9 (VARCHAR2(30), CSID=1): 'RECEIVED'

6 - :B8 (DATE): 06/04/2012 00:00:00

7 - :B7 (DATE): 06/14/2012 23:59:59

8 - :B6 (NUMBER): 9

9 - :B5 (VARCHAR2(30), CSID=1): 'OPEN'

10 - :B11 (VARCHAR2(30), CSID=1): 'CONFIRMED'

11 - :B10 (VARCHAR2(30), CSID=1): 'REJECTED'

60 rows selected.

SQL>

SQL> select * from table(dbms_xplan.DISPLAY_AWR('frgzxkprkwntn','3487426888','2694280230','peeked_binds'));

PLAN_TABLE_OUTPUT

SQL_ID frgzxkprkwntn

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

SELECT COUNT(TBTC.REQUEST_OBJECT_ID) FROM TBTC_REQUEST TBTC,

TBLK_REQUEST_TX TBLK WHERE TBTC.REQUEST_TYPE_CODE = :B4 AND

TBTC.DIRECTION = :B3 AND TBTC.REQUEST_STATUS_CODE = :B2 AND

TBLK.REQUEST_OBJECT_ID = TBTC.REQUEST_OBJECT_ID AND

TBLK.REQUEST_TX_TYPE_CODE = :B1 AND EXISTS ( SELECT NULL FROM

MYTB_TX_HELPM_ENTRY MYTB, TB09_TX_ACTIVITY TB09 WHERE

(TBLK.REQUEST_TX_OBJECT_ID = MYTB.REQUEST_TX_OBJECT_ID AND

MYTB.REQUEST_TX_OBJECT_ID = TB09.REQUEST_TX_OBJECT_ID) AND

MYTB.TX_HELPM_ENTRY_TYPE_CODE = :B9 AND MYTB.HELPM_TS > :B8 AND

MYTB.HELPM_TS < :B7 AND MYTB.REQUEST_TX_OBJECT_ID =

TBLK.REQUEST_TX_OBJECT_ID AND TB09.ACTIVITY_ID = :B6 AND

TB09.TX_ACTIVITY_STATUS_CODE = :B5 AND NOT EXISTS ( SELECT NULL FROM

MYTB_TX_HELPM_ENTRY B WHERE B.REQUEST_TX_OBJECT_ID =

MYTB.REQUEST_TX_OBJECT_ID AND B.HELPM_CARRIER_ID =

MYTB.HELPM_CARRIER_ID AND (B.TX_HELPM_ENTRY_TYPE_CODE = :B11 OR

B.TX_HELPM_ENTRY_TYPE_CODE = :B10 ) ) )

Plan hash value: 3487426888

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

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

| 0 | SELECT STATEMENT | | | | 8 (100)| |

| 1 | SORT AGGREGATE | | 1 | 57 | | |

| 2 | NESTED LOOPS | | | | | |

| 3 | NESTED LOOPS | | 1 | 57 | 8 (13)| 00:00:01 |

| 4 | NESTED LOOPS | | 1 | 32 | 7 (15)| 00:00:01 |

| 5 | VIEW | VW_SQ_1 | 1 | 13 | 5 (0)| 00:00:01 |

| 6 | HASH UNIQUE | | 1 | 68 | | |

| 7 | FILTER | | | | | |

| 8 | NESTED LOOPS | | | | | |

| 9 | NESTED LOOPS | | 1 | 68 | 5 (0)| 00:00:01 |

| 10 | NESTED LOOPS ANTI | | 1 | 48 | 4 (0)| 00:00:01 |

| 11 | TABLE ACCESS BY INDEX ROWID| MYTB_TX_HELPM_ENTRY | 1 | 28 | 4 (0)| 00:00:01 |

| 12 | INDEX RANGE SCAN | MYTB_I_HELPM_TS_TXOBJ | 1 | | 3 (0)| 00:00:01 |

| 13 | INLIST ITERATOR | | | | | |

| 14 | INDEX UNIQUE SCAN | MYTB_C_PK | 1102K| 21M| 0 (0)| |

| 15 | INDEX RANGE SCAN | TB09_I_REQUEST_TX_OBJECT_ID | 3 | | 0 (0)| |

| 16 | TABLE ACCESS BY INDEX ROWID | TB09_TX_ACTIVITY | 1 | 20 | 1 (0)| 00:00:01 |

| 17 | TABLE ACCESS BY INDEX ROWID | TBLK_REQUEST_TX | 1 | 19 | 1 (0)| 00:00:01 |

| 18 | INDEX UNIQUE SCAN | TBLK_C_PK | 1 | | 0 (0)| |

| 19 | INDEX RANGE SCAN | TBTC_I_STATUS_REQ_OBJ_ID | 1 | | 0 (0)| |

| 20 | TABLE ACCESS BY INDEX ROWID | TBTC_REQUEST | 1 | 25 | 1 (0)| 00:00:01 |

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

Peeked Binds (identified by position):

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

1 - :B4 (VARCHAR2(30), CSID=1): 'PORT'

2 - :B3 (VARCHAR2(30), CSID=1): 'O'

3 - :B2 (VARCHAR2(30), CSID=1): 'CTVR CNFM'

4 - :B1 (VARCHAR2(30), CSID=1): 'BPCN'

5 - :B9 (VARCHAR2(30), CSID=1): 'RECEIVED'

6 - :B8 (DATE): 07/16/2012 00:00:00

7 - :B7 (DATE): 07/16/2012 11:52:12

8 - :B6 (NUMBER): 9

9 - :B5 (VARCHAR2(30), CSID=1): 'OPEN'

10 - :B11 (VARCHAR2(30), CSID=1): 'CONFIRMED'

11 - :B10 (VARCHAR2(30), CSID=1): 'REJECTED'

62 rows selected.

SQL>

(3) 利用WRI$_OPTSTAT_TAB_HISTORY看table的历史统计信息：

SQL>  l
  1  SELECT ob.owner, ob.object_name, ob.subobject_name, ob.object_type,obj#, savtime, flags, rowcnt, blkcnt, avgrln ,samplesize, analyzetime, cachedblk, cachehit, logicalread
  2  FROM sys.WRI$_OPTSTAT_TAB_HISTORY, dba_objects ob
  3  WHERE owner=upper('&OWNER')
  4  and object_name=upper('&TABLE_NAME')
  5  and object_type in ('TABLE')
  6* and object_id=obj#
SQL> 
 OWNER                          OBJECT_NAME        SUBOBJECT_NAME                 OBJECT_TYPE               OBJ# SAVTIME                                                                          FLAGS     ROWCNT     BLKCNT     AVGRLN SAMPLESIZE ANALYZETI  CACHEDBLK   CACHEHIT LOGICALREAD
------------------------------ ------------------ ------------------------------ ------------------- ---------- --------------------------------------------------------------------------- ---------- ---------- ---------- ---------- ---------- --------- ---------- ---------- -----------
KRADSNP                        L901_REQQESM                                      TABLE                    14444 16-JUN-12 01.00.29.995699 AM +10:00                                                 10    1424933      29130        125      18028 15-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 17-JUN-12 01.00.31.984135 AM +10:00                                                 10    1428883      29130        125      16538 16-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 18-JUN-12 01.00.32.334285 AM +10:00                                                 10    1319051      29130        125      17247 17-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 19-JUN-12 01.00.29.984877 AM +10:00                                                 10    1322830      29130        125      17082 18-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 20-JUN-12 01.00.30.797670 AM +10:00                                                 10    1346647      29130        126      16568 19-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 21-JUN-12 01.00.29.440412 AM +10:00                                                 10    1366048      29130        125      15637 20-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 22-JUN-12 01.00.28.382793 AM +10:00                                                 10    1349705      29130        124      18259 21-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 23-JUN-12 01.00.28.825838 AM +10:00                                                 10    1368109      29130        126      17594 22-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 24-JUN-12 01.00.33.820628 AM +10:00                                                 10    1357332      29130        125      16569 23-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 25-JUN-12 01.00.26.874720 AM +10:00                                                 10    1301871      29130        124      15469 24-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 26-JUN-12 01.00.29.456753 AM +10:00                                                 10    1290826      29130        125      15635 25-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 27-JUN-12 01.00.31.494028 AM +10:00                                                 10    1314902      29130        125      17265 26-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 28-JUN-12 01.00.28.557591 AM +10:00                                                 10    1317162      29130        125      15954 27-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 29-JUN-12 01.00.29.486669 AM +10:00                                                 10    1339159      29130        125      16541 28-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 30-JUN-12 01.00.31.189966 AM +10:00                                                 10    1325110      29130        125      17849 29-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 01-JUL-12 01.00.33.626269 AM +10:00                                                 10    1360004      29130        126      15343 30-JUN-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 02-JUL-12 01.00.30.358059 AM +10:00                                                 10    1300221      29130        124      15688 01-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 03-JUL-12 01.00.30.497122 AM +10:00                                                 10    1300176      29130        125      18058 02-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 04-JUL-12 01.00.32.501247 AM +10:00                                                 10    1299742      29130        125      14878 03-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 05-JUL-12 01.00.29.354968 AM +10:00                                                 10    1316943      29130        125      17739 04-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 06-JUL-12 01.00.31.051355 AM +10:00                                                 10    1321312      29130        126      15700 05-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 07-JUL-12 01.00.32.227695 AM +10:00                                                 10    1310964      29130        125      16257 06-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 08-JUL-12 01.00.34.881812 AM +10:00                                                 10    1330625      29130        125      15871 07-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 09-JUL-12 01.00.31.878459 AM +10:00                                                 10    1292054      29130        125      17255 08-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 10-JUL-12 01.00.32.263729 AM +10:00                                                 10    1298390      29130        124      16427 09-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 11-JUL-12 01.00.35.061859 AM +10:00                                                 10    1277699      29130        125      15476 10-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 12-JUL-12 01.00.33.607805 AM +10:00                                                 10    1292381      29130        126      15838 11-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 13-JUL-12 01.00.31.355977 AM +10:00                                                 10    1313700      29130        125      17322 12-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 14-JUL-12 01.00.34.465944 AM +10:00                                                 10    1325156      29130        125      19351 13-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 15-JUL-12 01.00.35.710237 AM +10:00                                                 10    1328732      29130        125      18537 14-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 16-JUL-12 01.00.29.063225 AM +10:00                                                 10    1267732      29130        126      16576 15-JUL-12
KRADSNP                        L901_REQQESM                                      TABLE                    14444 17-JUL-12 01.00.31.753118 AM +10:00                                                 10    1270792      29130        127      16013 16-JUL-12

32 rows selected.

SQL>

SQL> l

1 SELECT ob.owner, ob.object_name, ob.subobject_name, ob.object_type,obj#, savtime, flags, rowcnt, blkcnt, avgrln ,samplesize, analyzetime, cachedblk, cachehit, logicalread

2 FROM sys.WRI$_OPTSTAT_TAB_HISTORY, dba_objects ob

3 WHERE owner=upper('&OWNER')

4 and object_name=upper('&TABLE_NAME')

5 and object_type in ('TABLE')

6* and object_id=obj#

SQL>

OWNER OBJECT_NAME SUBOBJECT_NAME OBJECT_TYPE OBJ# SAVTIME FLAGS ROWCNT BLKCNT AVGRLN SAMPLESIZE ANALYZETI CACHEDBLK CACHEHIT LOGICALREAD

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

KRADSNP L901_REQQESM TABLE 14444 16-JUN-12 01.00.29.995699 AM +10:00 10 1424933 29130 125 18028 15-JUN-12

KRADSNP L901_REQQESM TABLE 14444 17-JUN-12 01.00.31.984135 AM +10:00 10 1428883 29130 125 16538 16-JUN-12

KRADSNP L901_REQQESM TABLE 14444 18-JUN-12 01.00.32.334285 AM +10:00 10 1319051 29130 125 17247 17-JUN-12

KRADSNP L901_REQQESM TABLE 14444 19-JUN-12 01.00.29.984877 AM +10:00 10 1322830 29130 125 17082 18-JUN-12

KRADSNP L901_REQQESM TABLE 14444 20-JUN-12 01.00.30.797670 AM +10:00 10 1346647 29130 126 16568 19-JUN-12

KRADSNP L901_REQQESM TABLE 14444 21-JUN-12 01.00.29.440412 AM +10:00 10 1366048 29130 125 15637 20-JUN-12

KRADSNP L901_REQQESM TABLE 14444 22-JUN-12 01.00.28.382793 AM +10:00 10 1349705 29130 124 18259 21-JUN-12

KRADSNP L901_REQQESM TABLE 14444 23-JUN-12 01.00.28.825838 AM +10:00 10 1368109 29130 126 17594 22-JUN-12

KRADSNP L901_REQQESM TABLE 14444 24-JUN-12 01.00.33.820628 AM +10:00 10 1357332 29130 125 16569 23-JUN-12

KRADSNP L901_REQQESM TABLE 14444 25-JUN-12 01.00.26.874720 AM +10:00 10 1301871 29130 124 15469 24-JUN-12

KRADSNP L901_REQQESM TABLE 14444 26-JUN-12 01.00.29.456753 AM +10:00 10 1290826 29130 125 15635 25-JUN-12

KRADSNP L901_REQQESM TABLE 14444 27-JUN-12 01.00.31.494028 AM +10:00 10 1314902 29130 125 17265 26-JUN-12

KRADSNP L901_REQQESM TABLE 14444 28-JUN-12 01.00.28.557591 AM +10:00 10 1317162 29130 125 15954 27-JUN-12

KRADSNP L901_REQQESM TABLE 14444 29-JUN-12 01.00.29.486669 AM +10:00 10 1339159 29130 125 16541 28-JUN-12

KRADSNP L901_REQQESM TABLE 14444 30-JUN-12 01.00.31.189966 AM +10:00 10 1325110 29130 125 17849 29-JUN-12

KRADSNP L901_REQQESM TABLE 14444 01-JUL-12 01.00.33.626269 AM +10:00 10 1360004 29130 126 15343 30-JUN-12

KRADSNP L901_REQQESM TABLE 14444 02-JUL-12 01.00.30.358059 AM +10:00 10 1300221 29130 124 15688 01-JUL-12

KRADSNP L901_REQQESM TABLE 14444 03-JUL-12 01.00.30.497122 AM +10:00 10 1300176 29130 125 18058 02-JUL-12

KRADSNP L901_REQQESM TABLE 14444 04-JUL-12 01.00.32.501247 AM +10:00 10 1299742 29130 125 14878 03-JUL-12

KRADSNP L901_REQQESM TABLE 14444 05-JUL-12 01.00.29.354968 AM +10:00 10 1316943 29130 125 17739 04-JUL-12

KRADSNP L901_REQQESM TABLE 14444 06-JUL-12 01.00.31.051355 AM +10:00 10 1321312 29130 126 15700 05-JUL-12

KRADSNP L901_REQQESM TABLE 14444 07-JUL-12 01.00.32.227695 AM +10:00 10 1310964 29130 125 16257 06-JUL-12

KRADSNP L901_REQQESM TABLE 14444 08-JUL-12 01.00.34.881812 AM +10:00 10 1330625 29130 125 15871 07-JUL-12

KRADSNP L901_REQQESM TABLE 14444 09-JUL-12 01.00.31.878459 AM +10:00 10 1292054 29130 125 17255 08-JUL-12

KRADSNP L901_REQQESM TABLE 14444 10-JUL-12 01.00.32.263729 AM +10:00 10 1298390 29130 124 16427 09-JUL-12

KRADSNP L901_REQQESM TABLE 14444 11-JUL-12 01.00.35.061859 AM +10:00 10 1277699 29130 125 15476 10-JUL-12

KRADSNP L901_REQQESM TABLE 14444 12-JUL-12 01.00.33.607805 AM +10:00 10 1292381 29130 126 15838 11-JUL-12

KRADSNP L901_REQQESM TABLE 14444 13-JUL-12 01.00.31.355977 AM +10:00 10 1313700 29130 125 17322 12-JUL-12

KRADSNP L901_REQQESM TABLE 14444 14-JUL-12 01.00.34.465944 AM +10:00 10 1325156 29130 125 19351 13-JUL-12

KRADSNP L901_REQQESM TABLE 14444 15-JUL-12 01.00.35.710237 AM +10:00 10 1328732 29130 125 18537 14-JUL-12

KRADSNP L901_REQQESM TABLE 14444 16-JUL-12 01.00.29.063225 AM +10:00 10 1267732 29130 126 16576 15-JUL-12

KRADSNP L901_REQQESM TABLE 14444 17-JUL-12 01.00.31.753118 AM +10:00 10 1270792 29130 127 16013 16-JUL-12

32 rows selected.

SQL>

同理，看索引的历史统计信息可以用WRI$_OPTSTAT_IND_HISTORY。

(4) 关于Exadata中的执行计划。
在Exadata中，由于存在storage index和smart scan，传统的执行计划不一定是最佳，因为如果能在Exadata storage server这一层中，进行抽取所需的数据，把过滤之后的数据传给database server，这样效率会高很多。所以我们可以试试尽量走全表扫描，或者index full scan，不要走index fast full scan。
如果走表的全表扫描，你会看到在执行计划中，有table access storage full，而不是我们平时的table access full，这是有用到smart scan的一个标准：

------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                          | Name                       | Starts | E-Rows | A-Rows |   A-Time   | Buffers | Reads  |
------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                   |                            |      1 |        |  14604 |00:03:32.09 |     740K|    615K| 
|*  1 |  HASH JOIN OUTER                   |                            |      1 |  14604 |  14604 |00:03:32.09 |     740K|    615K| 
|   2 |   VIEW                             |                            |      1 |  14604 |  14604 |00:00:00.14 |   12708 |      0 | 
|   3 |    HASH GROUP BY                   |                            |      1 |  14604 |  14604 |00:00:00.14 |   12708 |      0 | 
|   4 |     TABLE ACCESS STORAGE FULL      | KDS_SP_ORSAR_OM_DASDQ_TEMP |      1 |    390K|    390K|00:00:00.11 |   12708 |      0 | 
|   5 |   VIEW                             |                            |      1 |  25723 |  12200 |00:03:31.94 |     728K|    615K| 
|   6 |    HASH GROUP BY                   |                            |      1 |  25723 |  12200 |00:03:31.94 |     728K|    615K| 
|*  7 |     HASH JOIN                      |                            |      1 |  25723 |    548K|00:03:32.07 |     728K|    615K| 
|   8 |      TABLE ACCESS STORAGE FULL     | kDS_CP_QUOTAALON_HQADERS   |      1 |     10M|     10M|00:00:01.44 |   99833 |      0 | 
|*  9 |      HASH JOIN                     |                            |      1 |     46M|    627M|00:02:03.78 |     628K|    615K| 
|  10 |       VIEW                         | VW_GBF_14                  |      1 |  14604 |  14604 |00:00:00.14 |   12708 |      0 | 
|  11 |        HASH GROUP BY               |                            |      1 |  14604 |  14604 |00:00:00.14 |   12708 |      0 | 
|  12 |         VIEW                       |                            |      1 |  14604 |  14604 |00:00:00.14 |   12708 |      0 |
|  13 |          HASH GROUP BY             |                            |      1 |  14604 |  14604 |00:00:00.13 |   12708 |      0 |
|  14 |           TABLE ACCESS STORAGE FULL| KDS_SP_ORSAR_OM_DASDQ_TEMP |      1 |    390K|    390K|00:00:00.10 |   12708 |      0 |
|  15 |       TABLE ACCESS STORAGE FULL    | kDS_CP_QUOTALAON_LMJES     |      1 |    180M|    180M|00:00:20.74 |     615K|    615K|
------------------------------------------------------------------------------------------------------------------------------------

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

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

| 0 | SELECT STATEMENT | | 1 | | 14604 |00:03:32.09 | 740K| 615K|

|* 1 | HASH JOIN OUTER | | 1 | 14604 | 14604 |00:03:32.09 | 740K| 615K|

| 2 | VIEW | | 1 | 14604 | 14604 |00:00:00.14 | 12708 | 0 |

| 3 | HASH GROUP BY | | 1 | 14604 | 14604 |00:00:00.14 | 12708 | 0 |

| 4 | TABLE ACCESS STORAGE FULL | KDS_SP_ORSAR_OM_DASDQ_TEMP | 1 | 390K| 390K|00:00:00.11 | 12708 | 0 |

| 5 | VIEW | | 1 | 25723 | 12200 |00:03:31.94 | 728K| 615K|

| 6 | HASH GROUP BY | | 1 | 25723 | 12200 |00:03:31.94 | 728K| 615K|

|* 7 | HASH JOIN | | 1 | 25723 | 548K|00:03:32.07 | 728K| 615K|

| 8 | TABLE ACCESS STORAGE FULL | kDS_CP_QUOTAALON_HQADERS | 1 | 10M| 10M|00:00:01.44 | 99833 | 0 |

|* 9 | HASH JOIN | | 1 | 46M| 627M|00:02:03.78 | 628K| 615K|

| 10 | VIEW | VW_GBF_14 | 1 | 14604 | 14604 |00:00:00.14 | 12708 | 0 |

| 11 | HASH GROUP BY | | 1 | 14604 | 14604 |00:00:00.14 | 12708 | 0 |

| 12 | VIEW | | 1 | 14604 | 14604 |00:00:00.14 | 12708 | 0 |

| 13 | HASH GROUP BY | | 1 | 14604 | 14604 |00:00:00.13 | 12708 | 0 |

| 14 | TABLE ACCESS STORAGE FULL| KDS_SP_ORSAR_OM_DASDQ_TEMP | 1 | 390K| 390K|00:00:00.10 | 12708 | 0 |

| 15 | TABLE ACCESS STORAGE FULL | kDS_CP_QUOTALAON_LMJES | 1 | 180M| 180M|00:00:20.74 | 615K| 615K|

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

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