有关缩小undotbs1表空间的datafile大小

oracle硬盘没有空间了，oracle不能启动，报错如下：
[oracle@rewin-db oracle]$ sqlplus "/as sysdba"

SQL*Plus: Release 9.2.0.1.0 - Production on Wed Mar 19 15:05:35 2008

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

ERROR:
ORA-09817: Write to audit file failed.
Linux Error: 28: No space left on device
ORA-09945: Unable to initialize the audit trail file
Linux Error: 28: No space left on device

解决办法：
把 /oracle/ora9.2/rdbms/audit 目录下的文件删掉

启动后查看oracle重做表空间占用空闲空间较大，为15G，表空间被用过了,收不回去,创建一个换过去!

顾UNDO的表空间最好不要设为UNLIMITED!方法如下：


-- 创建备用undo表空间
SQL> create undo tablespace UNDOTBS2 datafile '/ora_disk/rewin/UNDOTBS2.dbf' size 1000m;
需要设置一下自动增长？？

Tablespace created

-- 切换undo表空间

SQL> alter system set undo_tablespace=UNDOTBS2 scope=spfile;

SQL> shutdown immediate

- drop原表空间
drop tablespace UNDOTBS1 including contents and datafiles;

-- 创建原undo表空间
SQL> create undo tablespace UNDOTBS1 datafile '/ora_disk/rewin/UNDOTBS1.dbf' size 1000m;

Tablespace created

-- 切换undo表空间
SQL> alter system set undo_tablespace=UNDOTBS1 scope=spfile;

System altered.

-- 关闭重起并把备用undo表空间drop
SQL> shutdown immediate
/
SQL> startup
/
SQL> drop tablespace UNDOTBS2 including contents and datafiles;

有关缩小表空间的方法2:
注意在使用OEM查看表空间时要看清是否只有一个dbf文件.
alter database datafile '/u03/oradata/undotbs01.dbf' resize 2000M