Variable Size 37748736 bytes
Database Buffers 41943040 bytes
Redo Buffers 667648 bytes
Database mounted.
Database opened.
SQL>

 

3. 在特殊的情况下,你可能需要清除这个v$object_usage视图中的信息.

Oracle的说法是,在下一次收集该对象的索引使用情况时会自动覆盖上一次的信息,不提供清除手段.

稍微研究了一下.

v$object_usage是基于以下基表建立起来的:

create or replace view v$object_usage
(index_name, table_name, monitoring, used, start_monitoring, end_monitoring)
as
select io.name, t.name,
       decode(bitand(i.flags, 65536), 0, 'NO', 'YES'),
       decode(bitand(ou.flags, 1), 0, 'NO', 'YES'),
       ou.start_monitoring,
       ou.end_monitoring
from sys.obj$ io, sys.obj$ t, sys.ind$ i, sys.object_usage ou
where io.owner# = userenv('SCHEMAID')
  and i.obj# = ou.obj#
  and io.obj# = ou.obj#
  and t.obj# = i.bo#
/

                      

 

注意到v$object_usage关键信息来源于OBJECT_USAGE表.
另外我们可以注意一下,此处v$object_usage的查询基于userenv('SCHEMAID')建立.
所以以不同用户登录,你是无法看到其他用户的索引监视信息的,即使是dba,但是可以从object_usage表中得到.

 

SQL> select * from v$object_usage;



INDEX_NAME                     TABLE_NAME                     MON USE START_MONITORING    END_MONITORING

------------------------------ ------------------------------ --- --- ------------------- -------------------

PK_DEPT                        DEPT                           NO  YES 10/28/2004 10:55:19 10/28/2004 10:55:47



SQL> select * from object_usage;

select * from object_usage

              *

ERROR at line 1:

ORA-00942: table or view does not exist





SQL> connect /as sysdba

Connected.

SQL> /



      OBJ#      FLAGS START_MONITORING    END_MONITORING

---------- ---------- ------------------- -------------------

      6288          1 10/28/2004 10:55:19 10/28/2004 10:55:47     

                 

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