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案例:执行计划autotrace显示Statistics很多信息数值为0的原因

时间:2016-04-22 20:57   来源:Oracle研究中心   作者:惜分飞   点击:

天萃荷净 查看执行计划autotrace显示Statistics很多信息为0

一朋友使用autotrace查看数据库执行计划发现结果如下,Statistics中很多信息为0,这个肯定是不正常现象,什么都可以为0,consistent gets也不可能为0.

SQL> set autot on
SQL> select count(*) from RACV_DATA.PARTY_DUMMY;

  COUNT(*)
----------
        47

Elapsed: 00:00:00.00

Execution Plan
----------------------------------------------------------
Plan hash value: 3621440939

--------------------------------------------------------------------------
| Id  | Operation          | Name        | Rows  | Cost (%CPU)| Time     |
--------------------------------------------------------------------------
|   0 | SELECT STATEMENT   |             |     1 |     3   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE    |             |     1 |            |          |
|   2 |   TABLE ACCESS FULL| PARTY_DUMMY |    47 |     3   (0)| 00:00:01 |
--------------------------------------------------------------------------


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

解决方法

SQL>  select owner,object_name from dba_objects where object_name='PLAN_TABLE';

no rows selected

SQL> @?/rdbms/admin/utlxplan.sql

Table created.

重新查看Statistics信息

Statistics
----------------------------------------------------------
          0  recursive calls
          0  db block gets
          7  consistent gets
          0  physical reads
          0  redo size
        522  bytes sent via SQL*Net to client
        524  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
          0  sorts (memory)
          0  sorts (disk)
          1  rows processed

-----------------温馨提示--------------------
操作有风险,动手需谨慎
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最权威、专业的Oracle案例资源汇总之案例:执行计划autotrace显示Statistics很多信息数值为0的原因

本文由大师惜分飞原创分享,网址:http://www.oracleplus.net/arch/105.html

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关键词:

autotrace显示Statistics很多信息为0