非归档数据文件offline的恢复
本文主要介绍非归档模式下offline数据文件的恢复，测试过程如下：
SQL> select * from v$version where rownum<3;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bi
PL/SQL Release 10.2.0.5.0 - Production
SQL> archive log list;
Database log mode No Archive Mode
Automatic archival Disabled
Archive destination /u01/prod_arch
Oldest online log sequence 17
Current log sequence 19
---控件文件中的SCN
SQL> select file#,status,checkpoint_change# from v$datafile order by 1;
FILE# STATUS CHECKPOINT_CHANGE#
---------- ------- ------------------
1 SYSTEM 554606
2 ONLINE 554606
3 ONLINE 554606
4 ONLINE 554606
5 ONLINE 554606
--数据文件头中的SCN
SQL> select file#,status,checkpoint_change# from v$datafile_header order by 1;
FILE# STATUS CHECKPOINT_CHANGE#
---------- ------- ------------------
1 ONLINE 554606
2 ONLINE 554606
3 ONLINE 554606
4 ONLINE 554606
5 ONLINE 554606
--日志文件的情况
SQL> select * from v$Log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
1 1 19 52428800 1 NO CURRENT 543593 29-OCT-13
2 1 17 52428800 1 YES INACTIVE 500547 29-OCT-13
3 1 18 52428800 1 YES INACTIVE 521183 29-OCT-13
--offline数据文件5，在为进行日志切换的i情况下直接rcover然后在online就可以恢复。
SQL> alter database datafile 5 offline drop;
Database altered.
SQL> alter database datafile 5 online;
alter database datafile 5 online
*
ERROR at line 1:
ORA-01113: file 5 needs media recovery if it was restored from backup, or END BACKUP if it was not
ORA-01110: data file 5: '/u01/app/oracle/oradata/ptod/zxy01.dbf'
SQL> recover datafile 5;
Media recovery complete.
SQL> alter database datafile 5 online;
Database altered.
二、在日志被覆盖的情况下：
SQL>
alter system switch logfile;
System altered.
SQL> select file#,checkpoint_change# from v$datafile;
FILE# CHECKPOINT_CHANGE#
---------- ------------------
1 554973
2 554973
3 554973
4 554973
5 554973
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
1 1 22 52428800 1 NO INACTIVE 554969 30-OCT-13
2 1 23 52428800 1 NO INACTIVE 554971 30-OCT-13
3 1 24 52428800 1 NO CURRENT 554973 30-OCT-13
SQL> alter database datafile 5 offline drop;
Database altered.
SQL> alter system switch logfile;
System altered.
SQL> alter system switch logfile;
System altered.
SQL> alter system switch logfile;
System altered.
SQL> alter system switch logfile;
System altered.
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
1 1 28 52428800 1 NO CURRENT 555067 30-OCT-13
2 1 26 52428800 1 NO INACTIVE 555052 30-OCT-13
3 1 27 52428800 1 NO INACTIVE 555055 30-OCT-13
SQL> alter database datafile 5 online;
alter database datafile 5 online
*
ERROR at line 1:
ORA-01113: file 5 needs media recovery if it was restored from backup, or END BACKUP if it was not
ORA-01110: data file 5: '/u01/app/oracle/oradata/ptod/zxy01.dbf'
SQL> recover datafile 5;
ORA-00279: change 554973 generated at 10/30/2013 23:28:26 needed for thread 1
ORA-00289: suggestion : /u01/prod_arch/1_24_829999096.dbf
ORA-00280: change 554973 for thread 1 is in sequence #24
Specify log: {=suggested