Oracle执行分析详细 - 数据库编程

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

| 0 | SELECT STATEMENT | | 107 | 7276 | 3 (0)| 00:00:01 | | 1 | TABLE ACCESS FULL| EMPLOYEES | 107 | 7276 | 3 (0)| 00:00:01 |

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Statistics

---------------------------------------------------------- 0 recursive calls

0 db block gets 15 consistent gets

0 physical reads 0 redo size

9997 bytes sent via SQL*Net to client 569 bytes received via SQL*Net from client

9 SQL*Net roundtrips to/from client 0 sorts (memory)

0 sorts (disk) 107 rows processed

SQL> select * from employees;

107 rows selected.


Execution Plan
----------------------------------------------------------
Plan hash value: 1445457117

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| Id  | Operation         | Name      | Rows  | Bytes | Cost (%CPU)| Time     |
-------------------------------------------------------------------------------
|   0 | SELECT STATEMENT  |           |   107 |  7276 |     3   (0)| 00:00:01 |
|   1 |  TABLE ACCESS FULL| EMPLOYEES |   107 |  7276 |     3   (0)| 00:00:01 |
-------------------------------------------------------------------------------


Statistics
----------------------------------------------------------
          0  recursive calls
          0  db block gets
         15  consistent gets
          0  physical reads
          0  redo size
       9997  bytes sent via SQL*Net to client
        569  bytes received via SQL*Net from client
          9  SQL*Net roundtrips to/from client
          0  sorts (memory)
          0  sorts (disk)
        107  rows processed

在第一次查询employees时，产生了1次recursive Call，第二次查询的时候，因为数据字典的信息信息已经放在cache里，所以第二次的recursive call 为0. 如果第二次也没有完全cache，那么也是会产生recursive call，但次数比第一次少。

其他的从字面上面就可以看出来了，不需要多解释了吧。

Oracle执行分析详细(三)