有网友在itpub上反应11g中查看EM dbconsole显示数据文件的使用量为负数,如图：     实际上导致(EM ( EM Home page -> Administration Tab -> Storage -> Datafiles ))显示负的使用量的Bug在11g和10g中均存在，这里将这些bug列出来以供参考:   10g Enterprise Manager Shows Negative Utilisation For An Oracle Datafile.

Applies to:
Oracle Server - Enterprise Edition - Version: 10.2.0.1 to 10.2.0.3
This problem can occur on any platform.
Symptoms

EM ( EM Home page -> Administration Tab -> Storage -> Datafiles ) shows negative
utilization for some files. Value in Used (MB) column is negative.

Cause
This is because of Bug:5083393.

If the object is dropped and not purged, the value of FILE_ID / REL_FNO may be wrong in
DBA_FREE_SPACE and this cause EM to display wrong value in Used (MB) column.

Solution
If available, download Patch:5083393 to resolve this issue.
Note that this patch is available on 10.2.0.2/10.2.0.3 for some platforms at the
time of this writing this article (JULY 2007).

Workaround :
-------------
Purge all objects from the recycle bin.

$sqlplus "/as sysdba"
sql> purge dba_recyclebin

Hdr: 5083393 10.1.0.4 RDBMS 10.1.0.4 SPACE PRODID-5 PORTID-912
Abstract: VALUE OF FILE_ID AND RELATIVE_FNO OF DBA_FREE_SPACE IS DIFFERENT

PROBLEM:
--------
When the table is dropped, the value of the FILE_ID column and
the RELATIVE_FNO column of dba_free_space might be different.

SQL> select * from dba_free_space where tablespace_name = 'TBS_TEST1';

TABLESPACE_NAME FILE_ID BLOCK_ID    BYTES BLOCKS RELATIVE_FNO
--------------- ------- -------- -------- ------ ------------