BYTES/1024/1024
        16          0 ONLINE                     .000114441             .000114441          0
11 rows selected.
---------------
        12          0 ONLINE                     .000114441             .000114441          0
         5          1            1.22946167             1.22946167          0
空间已经释放。
ASMCMD> exit
       USN      XACTS STATUS          RSSIZE/1024/1024/1024 HWMSIZE/1024/1024/1024    SHRINKS
        19          0 ONLINE                     .000114441             .000114441          0
检查数据库表空间占用空间情况:
TABLESPACE_NAME                        GB
HY_DS_DEFAULT                           1

1.确认文件

         3          0             .13722229              .13722229          0
  3  union all
         4          1            1.27895355             1.27895355          0

6.删除原UNDO表空间

       USN      XACTS STATUS          RSSIZE/1024/1024/1024 HWMSIZE/1024/1024/1024    SHRINKS
TABLESPACE_NAME                        GB
3.创建新的UNDO表空间
USERS                          .004882813
---------- ---------- --------------------- ---------------------- ----------
ORA-1653: unable to extend table SYSMAN.MGMT_SYSTEM_ERROR_LOG by 8 in  tablespace SYSAUX
12 rows selected.
---------- ---------- --------------- --------------------- ---------------------- ----------
        17          0 ONLINE                     .000114441             .000114441          0
         6          0 PENDING OFFLINE             2.9671936              2.9671936          0
Used_MB      Mirror_used_MB
------------------------------ ----------
ORA-1237 signalled during: alter database datafile '+ORADG/danaly/datafile/sysaux.266.600173881' resize 800m...

         6          0             2.9671936              2.9671936          0
        11          0 ONLINE                     .000114441             .000114441          0
        20          0 ONLINE                     .000114441             .000114441          0
ORA-1653: unable to extend table SYSMAN.MGMT_SYSTEM_ERROR_LOG by 8 in  tablespace SYSAUX
         2          0            .071517944             .071517944          0
------------------------------ ----------
         0          0 ONLINE                     .000358582             .000358582          0

ORA-1653: unable to extend table SYSMAN.MGMT_SYSTEM_ERROR_LOG by 8 in  tablespace SYSAUX

11:32:11 SQL> /
  21625               21625
OS:Red Hat Enterprise Linux AS release 4 (Nahant)
SQL> select usn,xacts,rssize/1024/1024/1024,hwmsize/1024/1024/1024,shrinks
5.等待原UNDO表空间所有UNDO SEGMENT OFFLINE
         1          0            2.02474976             2.02474976          0
        15          1 ONLINE                     .000114441             .000114441          0
创建了新的UNDO表空间以后，如果不知道系统使用的是pfile还是spfile文件，应使用参数both,会同时修改spfile文件，避免出现冲突。

11 rows selected.

（本人经测试觉得其实是否可以用drop tablespace undotbs1 including contents and datafiles;直接连硬盘里面的dbf文件件一起删除）
       USN      XACTS STATUS          RSSIZE/1024/1024/1024 HWMSIZE/1024/1024/1024    SHRINKS
SYSTEM                         .478515625
          27810
  4  select tablespace_name,sum(bytes)/1024/1024/1024 GB

Tue Nov 29 23:31:38 2005
         0          0 ONLINE                     .000358582             .000358582          0
SQL> select tablespace_name,sum(bytes)/1024/1024/1024 GB
SYSAUX                         .634765625
         0          0            .000358582             .000358582          0
  2  where tablespace_name like 'UNDOTBS1';

CM_TS_DEFAULT                           5
不幸的发现，UNDO表空间已经扩展至27G，而TEMP表空间也扩展至20G，这2个表空间加起来占用了47G的磁盘空间,导致了空间不足。
SQL> alter system set undo_tablespace=undotbs2 scope=both;
SQL> create undo tablespace undotbs2 ;
SQL> select usn,xacts,status,rssize/1024/1024/1024,hwmsize/1024/1024/1024,shrinks
FILE_NAME
        14          0 ONLINE                     .000114441             .000114441          0
MMS_TS_DATA2                        1.375

登陆检查，发现是SYSAUX表空间空间用尽,不能扩展,尝试手工扩展SYSAUX表空间:
+ORADG/danaly/datafile/undotbs1.265.600173875
DB:Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
  5  from dba_temp_files group by tablespace_name order by GB;
[oracle@danaly ~]$ asmcmd
ORA-1653: unable to extend table SYSMAN.MGMT_SYSTEM_ERROR_LOG by 8 in  tablespace SYSAUX



MMS_TS_DATA1                            2
MMS_TS_DEFAULT                          2
一台Oracle10gR2数据库报出如下错误:
ASMCMD> du
---------- ---------- --------------- --------------------- ---------------------- ----------
是谁"偷偷的"用了那么多空间呢(本来有几十个G的Free磁盘空间的)?
        10          0            .625144958             .625144958          0
        12          0 ONLINE                     .000114441             .000114441          0
        18          0 ONLINE                     .000114441             .000114441          0
  2  from v$rollstat order by rssize;
  2  from dba_data_files group by tablespace_name
        19          0 ONLINE                     .000114441             .000114441          0

Tablespace dropped.
MMS_IDX_SJH                             2
15 rows selected.
ORA-1653: unable to extend table SYSMAN.MGMT_SYSTEM_ERROR_LOG by 8 in  tablespace SYSAUX
 alter database datafile '+ORADG/danaly/datafile/sysaux.266.600173881' resize 800m
---------- ---------- --------------- --------------------- ---------------------- ----------


TEMP                           20.5498047
再看:

Elapsed: 00:00:03.13

环境:
[oracle@danaly ~]$ export ORACLE_SID=+ASM
SQL> select file_name,bytes/1024/1024 from dba_data_files

         9          0            .236984253             .236984253          0
IVRCN_TS_DATA                           2
        13          0 ONLINE                     .000114441             .000114441          0
        17          0 ONLINE                     .000114441             .000114441          0
现在我们可以采用如下步骤回收UNDO空间:
        11          0 ONLINE                     .000114441             .000114441          0
4.切换UNDO表空间为新的UNDO表空间

出现ORA-1237错误，提示空间不足。这时候我才认识到是磁盘空间可能被用完了.

UNDOTBS1                       27.1582031
       USN      XACTS RSSIZE/1024/1024/1024 HWMSIZE/1024/1024/1024    SHRINKS
显然曾经有大事务占用了大量的UNDO表空间和Temp表空间，Oracle的AUM(Auto Undo Management)从出生以来就经常出现只扩展,不收缩(shrink)的情况(通常我们可以设置足够的UNDO表空间大小,然后取消其自动扩展属性).
        16          0 ONLINE                     .000114441             .000114441          0
  2 from v$rollstat order by rssize;
        20          0 ONLINE                     .000114441             .000114441          0
MINT_TS_DEFAULT                         1
System altered.

7.检查空间情况
--------------------------------------------------------------------------------
        13          0 ONLINE                     .000114441             .000114441          0
Tablespace created.
2.检查UNDO Segment状态
        15          1 ONLINE                     .000114441             .000114441          0

         8          0            1.27175903             1.27175903          0
UNDOTBS2                        .09765625
由于我使用的ASM管理,可以使用10gR2提供的信工具asmcmd来察看空间占用情况.
        14          0 ONLINE                     .000114441             .000114441          0
         7          0            1.56770325             1.56770325          0
（经测试，在9i环境下后面还要加上datafile '/opt/..../undotbs2.dbf' size 1024M）
        18          0 ONLINE                     .000114441             .000114441          0

11:34:00 SQL> drop tablespace undotbs1 including contents;
Elapsed: 00:00:00.00
WAPCM_TS_VISIT_DETAIL            .9765625