2.跨分区访问,依然是分区表的性能好，因为数据集中在了2个分区中，还是比访问
t1要少访问数据...
SQL> select * from t1 where object_id<4000;
已选择504448行。
执行计划
----------------------------------------------------------
Plan hash value: 3617692013
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 547K| 41M| 1070 (4)| 00:00:13 |
|* 1 | TABLE ACCESS FULL| T1 | 547K| 41M| 1070 (4)| 00:00:13 |
--------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("OBJECT_ID"<4000)
Note
-----
- dynamic sampling used for this statement
统计信息
----------------------------------------------------------
5 recursive calls
0 db block gets
38318 consistent gets
0 physical reads
0 redo size
15092711 bytes sent via SQL*Net to client
370304 bytes received via SQL*Net from client
33631 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
504448 rows processed
SQL> set timing on
SQL> select * from t1 where object_id<4000;
已选择504448行。
已用时间: 00: 00: 09.79
执行计划
----------------------------------------------------------
Plan hash value: 3617692013
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 547K| 41M| 1070 (4)| 00:00:13 |
|* 1 | TABLE ACCESS FULL| T1 | 547K| 41M| 1070 (4)| 00:00:13 |
--------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("OBJECT_ID"<4000)
Note
-----
- dynamic sampling used for this statement
统计信息
----------------------------------------------------------
0 recursive calls
0 db block gets
38236 consistent gets
0 physical reads
0 redo size
15092711 bytes sent via SQL*Net to client
370304 bytes received via SQL*Net from client
33631 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
504448 rows processed
SQL> select * from t where object_id<4000;
已选择504448行。
已用时间: 00: 00: 09.85
执行计划
----------------------------------------------------------
Plan hash value: 1571388083
--------------------------------------------------------------------------------
-----------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time
| Pstart| Pstop |
--------------------------------------------------------------------------------
-----------------
| 0 | SELECT STATEMENT | | 459K| 13M| 837 (53)| 00:00:11
| | |
| 1 | PARTITION RANGE ITERATOR| | 459K| 13M| 837 (53)| 00:00:11
| 1 | 2 |
| 2 | TABLE ACCESS FULL | T | 459K| 13M| 837 (53)| 00:00:11
| 1 | 2 |
--------------------------------------------------------------------------------
-----------------
Note
-----
- dynamic sampling used for this statement
统计信息
----------------------------------------------------------
69 recursive calls
1 db block gets
36078 consistent gets
946 physical reads
48432 redo size
15092711 bytes sent via SQL*Net to client
370304 bytes received via SQL*Net from client
33631 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
504448 rows processed
SQL> select * from t where object_id<4000;
已选择504448行。
已用时间: 00: 00: 10.12
执行计划
----------------------------------------------------------
Plan hash value: 1571388083
--------------------------------------------------------------------------------
-----------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time
| Pstart| Pstop |
--------------------------------------------------------------------------------
-----------------
| 0 | SELECT STATEMENT | | 459K| 13M| 837 (53)| 00:00:11
| | |
| 1 | PARTITION RANGE ITERATOR| | 459K| 13M| 837 (53)| 00:00:11
| 1 | 2 |
| 2 | TABLE ACCESS FULL | T | 459K| 13M| 837 (53)| 00:00:11
| 1 | 2 |
--------------------------------------------------------------------------------
-----------------
Note
-----
- dynamic sampling used for this statement
统计信息
----------------------------------------------------------
0 recursive calls
0 db block gets
35328 consistent gets
0 physical reads
0 redo size
15092711 bytes sent via SQL*Net to client
370304 bytes received via SQL*Net from client
33631 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
504448 rows processed
SQL>
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