使用bbed修改檔案頭，推進scn，恢複offline drop的資料檔案，bbedscn

使用bbed修改檔案頭，推進scn，恢複offline drop的資料檔案，bbedscn

 

 

最近處理了一起由於使用者操作錯誤導致的資料庫無法開啟的情況。

 

使用者資料庫為windows 64bit，資料庫版本為11.2.0.1，非歸檔模式。由於異常斷電，資料庫無法正常開啟，而且經過使用者的判斷使用了錯誤的offline drop操作。導致資料庫開啟後，記錄檔切換過多，無法使用recover命令。

因為中間沒有做其他動作，所以接到case後，這裡將受損的幾個資料檔案copy到linux下使用bbed進行修改，再copy回windows，成功跳過recover，開啟了offline drop的資料檔案。

 

情景還原：

 

 

sys@UTF8A> select name ,checkpoint_change# from v$datafile ; NAME                                              CHECKPOINT_CHANGE#--------------------------------------------------------------------/u01/apps/oracle/oradata/utf8a/system01.dbf                   1040256/u01/apps/oracle/oradata/utf8a/sysaux01.dbf                   1040256/u01/apps/oracle/oradata/utf8a/undotbs01.dbf                  1040256/u01/apps/oracle/oradata/utf8a/users01.dbf                    1039896  sys@UTF8A> select sequence#, group#,first_change#,statusfrom v$log ;  SEQUENCE#    GROUP# FIRST_CHANGE# STATUS---------- ---------- -----------------------------       19          1       1040256 CURRENT       17          2       1040250 INACTIVE       18          3       1040253 INACTIVE  sys@UTF8A> recover datafile 4  ;ORA-00279: change 1039896 generated at03/30/2015 09:31:05 needed for thread 1ORA-00289: suggestion :/u01/apps/oracle/product/11.2.0/dbhome_1/dbs/arch1_12_827004096.dbfORA-00280: change 1039896 for thread 1 isin sequence #12  Specify log: {<RET>=suggested |filename | AUTO | CANCEL}autoORA-00308: cannot open archived log'/u01/apps/oracle/product/11.2.0/dbhome_1/dbs/arch1_12_827004096.dbf'ORA-27037: unable to obtain file statusLinux-x86_64 Error: 2: No such file ordirectoryAdditional information: 3  ORA-00308: cannot open archived log'/u01/apps/oracle/product/11.2.0/dbhome_1/dbs/arch1_12_827004096.dbf'ORA-27037: unable to obtain file statusLinux-x86_64 Error: 2: No such file ordirectoryAdditional information: 3

 

 

sequence已經過去，無法執行恢複，所以這裡只能使用bbed修改檔案頭了。歸檔以及備份真的很重要。

 

block為8192。

flist：

 

1/u01/apps/oracle/oradata/utf8a/system01.dbf 754974720

2/u01/apps/oracle/oradata/utf8a/sysaux01.dbf 566231040

3/u01/apps/oracle/oradata/utf8a/undotbs01.dbf 83886080

4/u01/apps/oracle/oradata/utf8a/users01.dbf 9175040

 

 

如何初始化bbed環境，以及各種bbed版本的下載，見我的部落格

http://blog.csdn.net/renfengjun/article/details/7944629

 

這裡不再重複贅述。

 

 

先關閉資料庫並且啟動到mount狀態。

 

 

 

sys@UTF8A> selectfile#,change#,online_status from v$recover_file ;     FILE#    CHANGE# ONLINE_---------- ---------- -------        4    1039896 OFFLINE sys@UTF8A> select name ,checkpoint_change# from v$datafile ; NAME                                              CHECKPOINT_CHANGE#--------------------------------------------------------------------/u01/apps/oracle/oradata/utf8a/system01.dbf                   1041564/u01/apps/oracle/oradata/utf8a/sysaux01.dbf                   1041564/u01/apps/oracle/oradata/utf8a/undotbs01.dbf                  1041564/u01/apps/oracle/oradata/utf8a/users01.dbf                    1039896

 

 

記得修改前先備份所有的資料庫檔案。

 

 

BBED> set file 4       FILE#           4 BBED> p kcvfhckpstruct kcvfhckp, 36 bytes                   @484      struct kcvcpscn, 8 bytes                @484          ub4 kscnbas                           @484      0x000fde18     ub2 kscnwrp                          @488      0x0000  ub4 kcvcptim                            @492      0x34321859  ub2 kcvcpthr                            @496      0x0001  union u, 12 bytes                       @500         struct kcvcprba, 12 bytes            @500            ub4 kcrbaseq                      @500      0x0000000c        ub4 kcrbabno                      @504      0x00000015        ub2 kcrbabof                      @508      0x0010  ub1 kcvcpetb[0]                          @512      0x02  ub1 kcvcpetb[1]                         @513      0x00  ub1 kcvcpetb[2]                         @514      0x00  ub1 kcvcpetb[3]                         @515      0x00  ub1 kcvcpetb[4]                         @516      0x00  ub1 kcvcpetb[5]                         @517      0x00  ub1 kcvcpetb[6]                         @518      0x00  ub1 kcvcpetb[7]                         @519      0x00 

 注意offset 484 ， kscnbas為資料檔案現在的scn。

使用計算機計算後0x000fde18，得到的十進位數字為1039896，確認無誤，只要修改scn為最新的1041564，即可開啟損壞的資料檔案。

 

 

BBED> d /v dba 4,1 offset 484 count 16 File: /u01/apps/oracle/oradata/utf8a/users01.dbf(4) Block: 1      Offsets:  484 to  499 Dba:0x01000001------------------------------------------------------- 18de0f00 00000000 59183234 01000000 l ......Y.24....  <16 bytes per line> 

 

因為是這裡為linux x64 ，為little endian。

1039896=18de0f00

1041564=9ce40f00

 

 

直接修改即可。

 

 

BBED> set mode edit       MODE            Edit BBED> m /x 9ce40f dba 4,1 offset 484 File:/u01/apps/oracle/oradata/utf8a/users01.dbf (4) Block: 1                Offsets:  484 to 499           Dba:0x01000001------------------------------------------------------------------------ 9ce40f00 00000000 59183234 01000000  <32 bytes per line>   BBED> m /x 9ce40f dba 4,1 offset 484 File: /u01/apps/oracle/oradata/utf8a/users01.dbf(4) Block: 1                Offsets:  484 to 499           Dba:0x01000001------------------------------------------------------------------------ 9ce40f00 00000000 59183234 01000000  <32 bytes per line> BBED> sumCheck value for File 4, Block 1:current = 0x5f67, required = 0x65e3 BBED> sum applyCheck value for File 4, Block 1:current = 0x65e3, required = 0x65e3

 

 

 完成任務

 

 sys@UTF8A> alter database datafile 4online ; Database altered. sys@UTF8A> selectfile#,change#,online_status from v$recover_file ;     FILE#    CHANGE# ONLINE_---------- ---------- -------        4    1041564 ONLINE sys@UTF8A> alter database datafile 4online ; Database altered. sys@UTF8A> alter database open ;alter database open*ERROR at line 1:ORA-01113: file 4 needs media recoveryORA-01110: data file 4:'/u01/apps/oracle/oradata/utf8a/users01.dbf'  sys@UTF8A> recover datafile 4 ;Media recovery complete.sys@UTF8A> alter database open ; Database altered. sys@UTF8A> select * from scott.emp where rownum<2 ;      EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM    DEPTNO---------- ---------- --------- ---------- --------- -------------------- ----------      7369 SMITH      CLERK           7902 17-DEC-80        800                    20

 

 

 完成後記得邏輯匯出所有使用者資料，並且完善備份計劃。