数据库的临时文件和undo文件不需要做备份,丢失后可以恢复,数据不会有丢失.一,临时表空间的文件丢失后,在数据库启动后自动创建,不

数据库的临时文件和undo文件不需要做备份,丢失后可以恢复,数据不会有丢失.

一,临时表空间的文件丢失后,在数据库启动后自动创建,不需要做干预.

模拟:在数据库shutdown后将临时文件删除,启动的时候发现自动创建.

二,undo表空间对应的文件丢失.

模拟:在数据库shutdown后将undo文件删除,启动的时候出错:

ORA-01157: cannot identify/lock data file 2 - see DBWR trace file
ORA-01110: data file 2: 'D:\Oracle\PRODUCT\10.2.0\ORADATA\ORCL\UNDOTBS01.DBF'

恢复步骤:因为undo文件不保存数据,可以直接drop 后重建.

1,drop undo文件.

SQL> alter database datafile 'D:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\UNDOTBS01.DBF' offline drop;
Database altered.

2,将undo管理改为manual

SQL> alter system set undo_management='MANUAL' scope=spfile;

System altered.

3,重新启动数据库

SQL> shutdown immediate;
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.

SQL> startup
ORACLE instance started.
Total System Global Area 612368384 bytes
Fixed Size 1250428 bytes
Variable Size 2244100 bytes
Database Buffers 339738624 bytes
Redo Buffers 7135232 bytes
Database mounted.
Database opened.
4,将丢失文件的undo表空间drop后重建

SQL> drop tablespace undotbs1;
Tablespace dropped.

SQL> create undo tablespace UNDOTBS1 datafile 'D:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\UNDOTBS01.DBF' size 20M;
Tablespace created.
5,查看目前的数据库undo设置,需要将undo_management 改为auto.
SQL> show parameter undo
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string MANUAL
undo_retention integer 900
undo_tablespace string UNDOTBS1
SQL> alter system set undo_management='AUTO' scope=spfile;

SQL> alter system set undo_management='AUTO' scope=spfile;
System altered.
6,重新启动,数据库恢复成undo自动管理.

SQL> shutdown immediate;
SQL> startup