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: 00:00:00.00Execution 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.sqlTable 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
|