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