oracle 10g下范围分区扫描的几种方式

oracle 10g下有几种扫描方式，注意最后一种扫描方式，当对分区的列进行计算时，会不走分区。这跟对索引列进行计算会导致无法用索引一样。

--扫描单个分区 PARTITION RANGE SINGLE

--连续扫描多个分区 PARTITION RANGE ITERATOR

--不连续扫描多个分区 PARTITION RANGE INLIST

--扫描全分区 PARTITION RANGE ALL

SQL> drop table t_range purge;

SQL> create table t_range (id number not null PRIMARY KEY, test_date date) partition by range (test_date)

(

partition p_1 values less than (to_date('2013-12-01', 'yyyy-mm-dd')),

partition p_2 values less than (to_date('2014-02-01', 'yyyy-mm-dd')),

partition p_3 values less than (to_date('2014-03-01', 'yyyy-mm-dd')),

partition p_4 values less than (to_date('2014-04-01', 'yyyy-mm-dd')),

partition p_5 values less than (to_date('2014-05-01', 'yyyy-mm-dd')),

partition p_6 values less than (to_date('2014-06-01', 'yyyy-mm-dd')),

partition p_max values less than (MAXVALUE)

) nologging;

SQL> insert /*+append */ into t_range select rownum,

to_date(to_char(sysdate - 140, 'J') +

trunc(dbms_random.value(0, 80)),

'J')

from dual

connect by rownum <= 100000;

SQL> commit;

SQL> exec dbms_stats.gather_table_stats(user,'T_RANGE');

SQL> select to_char(t.test_date,'yyyy-MM'),count(1) from t_range t

group by to_char(t.test_date,'yyyy-MM');

TO_CHAR COUNT(1)

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

2014-01 38803

2014-03 11242

2013-12 15107

2014-02 34848

SQL> set autotrace traceonly

--扫描单个分区

SQL> select * from t_range where test_date = to_date('2014-04-28', 'yyyy-mm-dd');

运行计划

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

Plan hash value: 3010141842

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

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

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

| 0 | SELECT STATEMENT | | 1 | 22 | 2 (0)| 00:00:01 | | |

| 1 | PARTITION RANGE SINGLE| | 1 | 22 | 2 (0)| 00:00:01 | 5 | 5 |

|* 2 | TABLE ACCESS FULL | T_RANGE | 1 | 22 | 2 (0)| 00:00:01 | 5 | 5 |

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

Predicate Information (identified by operation id):

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

2 - filter("TEST_DATE"=TO_DATE('2014-04-28 00:00:00', 'yyyy-mm-dd hh24:mi:ss'))

统计信息

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

1 recursive calls

0 db block gets

3 consistent gets

0 physical reads

0 redo size

327 bytes sent via SQL*Net to client

374 bytes received via SQL*Net from client

1 SQL*Net roundtrips to/from client

0 sorts (memory)

0 sorts (disk)

0 rows processed

--连续扫描多个分区

SQL> select * from t_range

where test_date <= to_date('2014-04-28', 'yyyy-mm-dd')

and test_date >= to_date('2014-02-28', 'yyyy-mm-dd');

运行计划

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

Plan hash value: 1921532398

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

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

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

| 0 | SELECT STATEMENT | | 12556 | 147K| 28 (0)| 00:00:01 | | |

| 1 | PARTITION RANGE ITERATOR| | 12556 | 147K| 28 (0)| 00:00:01 | 3 | 5 |

|* 2 | TABLE ACCESS FULL | T_RANGE | 12556 | 147K| 28 (0)| 00:00:01 | 3 | 5 |

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

Predicate Information (identified by operation id):

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

2 - filter("TEST_DATE">=TO_DATE('2014-02-28 00:00:00', 'yyyy-mm-dd hh24:mi:ss') AND

"TEST_DATE"<=TO_DATE('2014-04-28 00:00:00', 'yyyy-mm-dd hh24:mi:ss'))

统计信息

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

1 recursive calls

0 db block gets

956 consistent gets

0 physical reads

0 redo size

309138 bytes sent via SQL*Net to client

9515 bytes received via SQL*Net from client

832 SQL*Net roundtrips to/from client

0 sorts (memory)

0 sorts (disk)

12453 rows processed

--不连续扫描多个分区

SQL> select * from t_range

where test_date = to_date('2014-04-28', 'yyyy-mm-dd')

or test_date = to_date('2014-02-28', 'yyyy-mm-dd');

运行计划

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

Plan hash value: 2021067984

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

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

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

| 0 | SELECT STATEMENT | | 1678 | 20136 | 21 (0)| 00:00:01 | | |

| 1 | PARTITION RANGE INLIST| | 1678 | 20136 | 21 (0)| 00:00:01 |KEY(I) |KEY(I) |

|* 2 | TABLE ACCESS FULL | T_RANGE | 1678 | 20136 | 21 (0)| 00:00:01 |KEY(I) |KEY(I) |

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

Predicate Information (identified by operation id):

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

2 - filter("TEST_DATE"=TO_DATE('2014-02-28 00:00:00', 'yyyy-mm-dd hh24:mi:ss') OR

"TEST_DATE"=TO_DATE('2014-04-28 00:00:00', 'yyyy-mm-dd hh24:mi:ss'))

统计信息

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

1 recursive calls

0 db block gets

175 consistent gets

0 physical reads

0 redo size

22646 bytes sent via SQL*Net to client

1265 bytes received via SQL*Net from client

82 SQL*Net roundtrips to/from client

0 sorts (memory)

0 sorts (disk)

1211 rows processed

--扫描全分区

SQL> select * from t_range where to_char(test_date,'yyyy-MM-dd')='2014-04-01';

运行计划

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

Plan hash value: 2128486036

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

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

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

| 0 | SELECT STATEMENT | | 994 | 11928 | 59 (4)| 00:00:01 | | |

| 1 | PARTITION RANGE ALL| | 994 | 11928 | 59 (4)| 00:00:01 | 1 | 7 |

|* 2 | TABLE ACCESS FULL | T_RANGE | 994 | 11928 | 59 (4)| 00:00:01 | 1 | 7 |

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

Predicate Information (identified by operation id):

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

2 - filter(TO_CHAR(INTERNAL_FUNCTION("TEST_DATE"),'yyyy-MM-dd')='2014-04-01')

统计信息

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

1 recursive calls

0 db block gets

272 consistent gets

0 physical reads

0 redo size

327 bytes sent via SQL*Net to client

374 bytes received via SQL*Net from client

1 SQL*Net roundtrips to/from client

0 sorts (memory)

0 sorts (disk)

0 rows processed