[小e笔记]之一步一步学习备份恢复——第三篇 数据库恢复案例(Part 5)

5 其他情况备份恢复

案例 1：归档模式下数据文件的丢失且无备份的恢复

方案：用户管理备份恢复

(1) 模拟数据

SQL> select * from test;
no rows selected
SQL> insert into test values(1,dbms_flashback.get_system_change_number);
1 row created.
SQL> commit;
Commit complete.
SQL> alter system switch logfile;
System altered.
SQL> select * from test;
ID SCN
---------- ----------
1 606740
2 606751
3 606758
4 606765
5 606771
(2) 损坏数据文件

[oracle@elvis elvis]$ rm -f test01.dbf
继续模拟数据
SQL> insert into test values(6,dbms_flashback.get_system_change_number);
insert into test values(6,dbms_flashback.get_system_change_number)
*
ERROR at line 1:
ORA-00376: file 5 cannot be read at this time
ORA-01110: data file 5: '/u01/oracle/oradata/elvis/test01.dbf'
(3) 重启数据库&恢复数据文件

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 598437888 bytes
Fixed Size 1338140 bytes
Variable Size 394265828 bytes
Database Buffers 197132288 bytes
Redo Buffers 5701632 bytes
Database mounted.
Database opened.
能开启数据库，是操作系统的原因（主要是linux），进程还是误判断了那个数据文件正常存在，大部分情况下是不能正常开启的，这个实验居然意外碰到了这个情况。

默认表空间如下：

[oracle@elvis elvis]$ ll
total 1747280
drwxr-xr-x 2 oracle oinstall 4096 Oct 8 08:58 bak
-rw-r----- 1 oracle oinstall 9748480 Oct 8 09:07 control01.ctl
-rw-r----- 1 oracle oinstall 52429312 Oct 8 09:07 redo01.log--重做日志文件丢失当前的会直接宕掉
-rw-r----- 1 oracle oinstall 52429312 Oct 8 09:07 redo02.log
-rw-r----- 1 oracle oinstall 52429312 Oct 8 09:07 redo03.log
-rw-r----- 1 oracle oinstall 629153792 Oct 8 09:07 sysaux01.dbf
-rw-r----- 1 oracle oinstall 734011392 Oct 8 09:07 system01.dbf
-rw-r----- 1 oracle oinstall 71311360 Oct 8 08:50 temp01.dbf
-rw-r----- 1 oracle oinstall 235937792 Oct 8 09:07 undotbs01.dbf
-rw-r----- 1 oracle oinstall 5251072 Oct 8 09:07 users01.dbf
红色部分是核心数据文件
看下test数据文件的状态

SQL> col file_name format a30
SQL> select file_name,file_id,tablespace_name,status,online_status from dba_data_files;
FILE_NAME FILE_ID TABLESPACE STATUS ONLINE_
------------------------------ ---------- ---------- --------- -------
/u01/oracle/oradata/elvis/syst 1 SYSTEM AVAILABLE SYSTEM
em01.dbf
/u01/oracle/oradata/elvis/sysa 2 SYSAUX AVAILABLE ONLINE
ux01.dbf
/u01/oracle/oradata/elvis/undo 3 UNDOTBS1 AVAILABLE ONLINE
tbs01.dbf
/u01/oracle/oradata/elvis/user 4 USERS AVAILABLE ONLINE
s01.dbf
FILE_NAME FILE_ID TABLESPACE STATUS ONLINE_
------------------------------ ---------- ---------- --------- -------
/u01/oracle/oradata/elvis/test 5 TEST AVAILABLE RECOVER
01.dbf
因为无备份只能这样

SQL> alter database create datafile '/u01/oracle/oradata/elvis/test01.dbf' as '/u01/oracle/oradata/elvis/test01.dbf';
Database altered.
SQL> recover datafile 5;
ORA-00279: change 511184 generated at 10/06/2012 18:29:47 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_06/o1_mf_1_50_870370r3_.arc
ORA-00280: change 511184 for thread 1 is in sequence #50
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
auto
ORA-00279: change 512064 generated at 10/06/2012 18:50:08 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_06/o1_mf_1_51_87037h5v_.arc
ORA-00280: change 512064 for thread 1 is in sequence #51
ORA-00279: change 512072 generated at 10/06/2012 18:50:23 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_06/o1_mf_1_52_87037wmo_.arc
ORA-00280: change 512072 for thread 1 is in sequence #52
ORA-00279: change 512080 generated at 10/06/2012 18:50:36 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_06/o1_mf_1_53_870388kw_.arc
ORA-00280: change 512080 for thread 1 is in sequence #53
ORA-00279: change 512087 generated at 10/06/2012 18:50:48 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_06/o1_mf_1_54_8703vpz3_.arc
ORA-00280: change 512087 for thread 1 is in sequence #54
ORA-00279: change 512548 generated at 10/06/2012 19:01:10 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_06/o1_mf_1_55_870ckxlg_.arc
ORA-00280: change 512548 for thread 1 is in sequence #55
ORA-00279: change 535327 generated at 10/06/2012 21:12:27 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_07/o1_mf_1_56_8729khvn_.arc
ORA-00280: change 535327 for thread 1 is in sequence #56
ORA-00279: change 558605 generated at 10/07/2012 14:50:19 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_07/o1_mf_1_57_872b169o_.arc
ORA-00280: change 558605 for thread 1 is in sequence #57
ORA-00279: change 561793 generated at 10/07/2012 14:58:46 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_07/o1_mf_1_58_872b1xrq_.arc
ORA-00280: change 561793 for thread 1 is in sequence #58
ORA-00279: change 561804 generated at 10/07/2012 14:59:09 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_07/o1_mf_1_59_872b2bfj_.arc
ORA-00280: change 561804 for thread 1 is in sequence #59
ORA-00279: change 561814 generated at 10/07/2012 14:59:22 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_07/o1_mf_1_60_872bgg4o_.arc
ORA-00280: change 561814 for thread 1 is in sequence #60
ORA-00279: change 562423 generated at 10/07/2012 15:05:50 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_07/o1_mf_1_61_872cd40l_.arc
ORA-00280: change 562423 for thread 1 is in sequence #61
ORA-00279: change 582475 generated at 10/07/2012 15:21:37 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_08/o1_mf_1_62_8748srx8_.arc
ORA-00280: change 582475 for thread 1 is in sequence #62
ORA-00279: change 606365 generated at 10/08/2012 08:49:57 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_08/o1_mf_1_63_87492gqg_.arc
ORA-00280: change 606365 for thread 1 is in sequence #63
ORA-00279: change 606750 generated at 10/08/2012 08:54:38 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_08/o1_mf_1_64_87492rtz_.arc
ORA-00280: change 606750 for thread 1 is in sequence #64
ORA-00279: change 606757 generated at 10/08/2012 08:54:48 needed for thread 1
ORA-00289: suggestion : /u01/oracle/flash_recovery_area/ELVIS/archivelog/2012_10_08/o1_mf_1_65_874933jv_.arc
ORA-00280: change 606757 for thread 1 is in sequence #65
Log applied.
Media recovery complete.
但恢复需要使数据文件和表空间online

SQL> select tablespace_name,status from dba_tablespaces;
TABLESPACE STATUS
---------- ---------
SYSTEM ONLINE
SYSAUX ONLINE
UNDOTBS1 ONLINE
TEMP ONLINE
USERS ONLINE
TEST ONLINE
6 rows selected.
SQL> col file_name format a50
SQL> select file_name,tablespace_name,status,online_status from dba_data_files;
FILE_NAME TABLESPACE STATUS ONLINE_
-------------------------------------------------- ---------- --------- -------
/u01/oracle/oradata/elvis/system01.dbf SYSTEM AVAILABLE SYSTEM
/u01/oracle/oradata/elvis/sysaux01.dbf SYSAUX AVAILABLE ONLINE
/u01/oracle/oradata/elvis/undotbs01.dbf UNDOTBS1 AVAILABLE ONLINE
/u01/oracle/oradata/elvis/users01.dbf USERS AVAILABLE ONLINE
/u01/oracle/oradata/elvis/test01.dbf TEST AVAILABLE OFFLINE
SQL> select file#,status from v$datafile;
FILE# STATUS
---------- -------
1 SYSTEM
2 ONLINE
3 ONLINE
4 ONLINE
5 OFFLINE
使数据文件online
SQL> alter database datafile 5 online;
Database altered.
SQL> select file_name,tablespace_name,status,online_status from dba_data_files;
FILE_NAME TABLESPACE STATUS ONLINE_
-------------------------------------------------- ---------- --------- -------
/u01/oracle/oradata/elvis/system01.dbf SYSTEM AVAILABLE SYSTEM
/u01/oracle/oradata/elvis/sysaux01.dbf SYSAUX AVAILABLE ONLINE
/u01/oracle/oradata/elvis/undotbs01.dbf UNDOTBS1 AVAILABLE ONLINE
/u01/oracle/oradata/elvis/users01.dbf USERS AVAILABLE ONLINE
/u01/oracle/oradata/elvis/test01.dbf TEST AVAILABLE ONLINE
SQL> select * from test;
ID SCN
---------- ----------
1 606740
2 606751
3 606758
4 606765
5 606771
数据全部恢复过来

总结：

在控制文件，日志文件，归档文件都完好的情况下，未备份的数据文件可以恢复且数据也不会丢失，但如果中间有resetlogs或者控制文件重建，这个就麻烦了。一定要做好备份，这种情况能恢复是运气好，且及时发现，要不肯定得丢失数据，总之做好有效备份才是硬道理。

elvis

2012.10.8

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