Table Space Query
select SEGMENT_NAME,bytes/1024/1024,a.* from dba_segments a
UNDO Table Space Size Full
数据库重启
SQL> shutdown abort
ORACLE 例程已经关闭。
SQL> quit
从 Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options 断
开
只有退出sqlplus环境，才能更改回滚段数据文件，删除回滚数据文件，模拟回滚段丢失
C:Documents and SettingsAdministrator>sqlplus "/as sysdba"
SQL*Plus: Release 10.2.0.4.0 - Production on 星期四 9月 9 22:23:50 2010
Copyright (c) 1982, 2007, Oracle. All Rights Reserved.
已连接到空闲例程。
SQL> startup
ORACLE 例程已经启动。
Total System Global Area 574619648 bytes
Fixed Size 1297944 bytes
Variable Size 234881512 bytes
Database Buffers 331350016 bytes
Redo Buffers 7090176 bytes
数据库装载完毕。
SQL> show parameter undo
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS1
SQL> alter system set undo_tablespace='undotbs4' scope=spfile;
http://www.itpub.net/thread-1346904-1-1.html
undo_management 设置与查询
3.问题处理
如果将UNDO置于自动管理模式下呢？这与undo_management参数（该参数的Oracle官方文档参考信息请访问：http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/initparams221.htm#CHDBHHJC）有关，该参数默认是MANUAL，需要手工将其调整为AUTO。
SQL> show parameter undo_management
NAME TYPE VALUE
------------------------------------ ----------- ---------------
undo_management string MANUAL
SQL> alter system set undo_management=AUTO scope=spfile;
System altered.
SQL> startup force nomount;
ORACLE instance started.
Total System Global Area 314572800 bytes
Fixed Size 1219184 bytes
Variable Size 96470416 bytes
Database Buffers 213909504 bytes
Redo Buffers 2973696 bytes
SQL> show parameter undo_management
NAME TYPE VALUE
------------------------------------ ----------- ---------------
undo_management string AUTO