rman制造坏块,bbed修复坏块

发表于 2013 年 2 月 21 日 由 惜分飞

在rman中有隐藏的命令clear,可以标记数据块为corrupt,从而实现数据库坏块试验,本篇blog通过dbv,bbed,table select来验证坏块的出现和修复
创建测试表

SQL>  create table t_xifenfei as  
  2   select object_id,object_name from dba_objects where rownum<10;

Table created.

SQL>  select rowid,
  2   dbms_rowid.rowid_relative_fno(rowid) rel_fno,
  3   dbms_rowid.rowid_block_number(rowid) block
  4   from chf.t_xifenfei;

ROWID                 REL_FNO      BLOCK
------------------ ---------- ----------
AAAStAAAEAAAACrAAA          4        171
AAAStAAAEAAAACrAAB          4        171
AAAStAAAEAAAACrAAC          4        171
AAAStAAAEAAAACrAAD          4        171
AAAStAAAEAAAACrAAE          4        171
AAAStAAAEAAAACrAAF          4        171
AAAStAAAEAAAACrAAG          4        171
AAAStAAAEAAAACrAAH          4        171
AAAStAAAEAAAACrAAI          4        171

9 rows selected.

SQL> alter system checkpoint;

System altered.

dbv验证坏块

[oracle@xifenfei ~]$ dbv file=/u01/oracle/oradata/ora11g/users01.dbf

DBVERIFY: Release 11.2.0.3.0 - Production on Sun Jan 20 09:12:16 2013

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

DBVERIFY - Verification starting : FILE = /u01/oracle/oradata/ora11g/users01.dbf


DBVERIFY - Verification complete

Total Pages Examined         : 7680
Total Pages Processed (Data) : 3776
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 167
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 744
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 2993
Total Pages Marked Corrupt   : 0
Total Pages Influx           : 0
Total Pages Encrypted        : 0
Highest block SCN            : 1006717955 (2956.1006717955)

这里创建了t_xifenfei表,数据存储在file 4 block 171中,现在该block一切正常,本试验就是要通过rman来使得该block corrupt,然后通过bbed来修复

bbed查看kcbh

BBED> set block 171
        BLOCK#          171

BBED> p kcbh
struct kcbh, 20 bytes                       @0       
   ub1 type_kcbh                            @0        0x06
   ub1 frmt_kcbh                            @1        0xa2
   ub1 spare1_kcbh                          @2        0x00
   ub1 spare2_kcbh                          @3        0x00
   ub4 rdba_kcbh                            @4        0x010000ab
   ub4 bas_kcbh                             @8        0x3c014bfe
   ub2 wrp_kcbh                             @12       0x0b8c
   ub1 seq_kcbh                             @14       0x02
   ub1 flg_kcbh                             @15       0x04 (KCBHFCKV)
   ub2 chkval_kcbh                          @16       0x6e0c  <--重点关注
   ub2 spare3_kcbh                          @18       0x0000

rman标记坏块

RMAN> BLOCKRECOVER DATAFILE 4 block 171 clear;

Starting recover at 20-JAN-13
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=18 device type=DISK
Finished recover at 20-JAN-13

dbv再次检查坏块

[oracle@xifenfei ~]$ dbv file=/u01/oracle/oradata/ora11g/users01.dbf

DBVERIFY: Release 11.2.0.3.0 - Production on Sun Jan 20 09:53:16 2013

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

DBVERIFY - Verification starting : FILE = /u01/oracle/oradata/ora11g/users01.dbf
Page 171 is marked corrupt
Corrupt block relative dba: 0x010000ab (file 4, block 171)
Bad check value found during dbv: 
Data in bad block:
 type: 6 format: 2 rdba: 0x010000ab
 last change scn: 0x0b8c.3c014bfe seq: 0x2 flg: 0x04
 spare1: 0x0 spare2: 0x0 spare3: 0x0
 consistency value in tail: 0x4bfe0602
 check value in block header: 0x6e0c
 computed block checksum: 0xb5bc


DBVERIFY - Verification complete

Total Pages Examined         : 7680
Total Pages Processed (Data) : 3775
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 167
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 744
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 2993
Total Pages Marked Corrupt   : 1
Total Pages Influx           : 1
Total Pages Encrypted        : 0
Highest block SCN            : 1006717955 (2956.1006717955)

尝试查询数据

SQL> select count(*) from t_xifenfei;
select count(*) from t_xifenfei
                     *
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 4, block # 171)
ORA-01110: data file 4: '/u01/oracle/oradata/ora11g/users01.dbf'

bbed验证坏块

BBED> set block 171
        BLOCK#          171

BBED> p kcbh
struct kcbh, 20 bytes                       @0       
   ub1 type_kcbh                            @0        0x06
   ub1 frmt_kcbh                            @1        0xa2
   ub1 spare1_kcbh                          @2        0x00
   ub1 spare2_kcbh                          @3        0x00
   ub4 rdba_kcbh                            @4        0x010000ab
   ub4 bas_kcbh                             @8        0x3c014bfe
   ub2 wrp_kcbh                             @12       0x0b8c
   ub1 seq_kcbh                             @14       0x02
   ub1 flg_kcbh                             @15       0x04 (KCBHFCKV)
   ub2 chkval_kcbh                          @16       0x6e0c  <--注意该值未变化
   ub2 spare3_kcbh                          @18       0x0000

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/users01.dbf
BLOCK = 171

Block 171 is corrupt
Corrupt block relative dba: 0x010000ab (file 0, block 171)
Bad check value found during verification
Data in bad block:
 type: 6 format: 2 rdba: 0x010000ab
 last change scn: 0x0b8c.3c014bfe seq: 0x2 flg: 0x04
 spare1: 0x0 spare2: 0x0 spare3: 0x0
 consistency value in tail: 0x4bfe0602
 check value in block header: 0x6e0c
 computed block checksum: 0xb5bc


DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 0
Total Blocks Failing   (Data) : 0
Total Blocks Processed (Index): 0
Total Blocks Failing   (Index): 0
Total Blocks Empty            : 0
Total Blocks Marked Corrupt   : 1
Total Blocks Influx           : 0
Message 531 not found;  product=RDBMS; facility=BBED

这里通过dbv,bbed,select table都证明rman能够标记block为Corrupt.
这里需要分析:block已经被标记,那证明该块肯定有修改,也就是说chkval_kcbh一定要变化,但是这里没有变化,证明该处异常

bbed修复rman生成坏块

BBED> sum apply
Warning: contents of previous BIFILE will be lost. Proceed? (Y/N) y
Check value for File 0, Block 171:
current = 0xdbb0, required = 0xdbb0

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/users01.dbf
BLOCK = 171


DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 1
Total Blocks Failing   (Data) : 0
Total Blocks Processed (Index): 0
Total Blocks Failing   (Index): 0
Total Blocks Empty            : 0
Total Blocks Marked Corrupt   : 0
Total Blocks Influx           : 0
Message 531 not found;  product=RDBMS; facility=BBED

bbed测试坏块已经修复

dbv验证坏块

[oracle@xifenfei ~]$ dbv file=/u01/oracle/oradata/ora11g/users01.dbf

DBVERIFY: Release 11.2.0.3.0 - Production on Sun Jan 20 10:01:46 2013

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

DBVERIFY - Verification starting : FILE = /u01/oracle/oradata/ora11g/users01.dbf

DBVERIFY - Verification complete

Total Pages Examined         : 7680
Total Pages Processed (Data) : 3776
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 167
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 744
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 2993
Total Pages Marked Corrupt   : 0
Total Pages Influx           : 0
Total Pages Encrypted        : 0
Highest block SCN            : 1006717955 (2956.1006717955)

dbv测试坏块也被修复

查询表验证

SQL> select count(*) from t_xifenfei;

  COUNT(*)
----------
         9

数据也可以正常查询,证明rman的坏块问题通过bbed解决

总结说明
1.我们可以通过rman的clear命令来标记坏块(BLOCKRECOVER DATAFILE file# BLOCK block1#, block2#, block3#… CLEAR ;)
2.我们可以通过bbed的sum apply命令来修复该类型坏块

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ORA-600 kghstack_free2异常恢复

发表于 2013 年 2 月 20 日 由 惜分飞

今天接触一案例ORA-00600[kghstack_free2],恢复起来很简单,顺便记录下，供其他人遇到类似情况参考.

Wed Feb 20 15:05:04 2013
SMON: enabling cache recovery
Wed Feb 20 15:05:05 2013
Successfully onlined Undo Tablespace 1.
Wed Feb 20 15:05:05 2013
SMON: enabling tx recovery
Wed Feb 20 15:05:06 2013
Errors in file f:\oracle\product\10.2.0\admin\cksoltp\bdump\cksoltp_smon_3556.trc:
ORA-00600: internal error code, arguments: [kghstack_free2], [], [], [], [], [], [], []

Wed Feb 20 15:05:06 2013
Database Characterset is AL32UTF8
replication_dependency_tracking turned off (no async multimaster replication found)
Wed Feb 20 15:05:08 2013
Errors in file f:\oracle\product\10.2.0\admin\cksoltp\bdump\cksoltp_smon_3556.trc:
ORA-07445: exception encountered: core dump [ACCESS_VIOLATION] [_kghstack_err+101] 
[PC:0x603CC77F] [ADDR:0x59004E04] [UNABLE_TO_READ] []
ORA-00600: internal error code, arguments: [kghstack_free2], [], [], [], [], [], [], []

Starting background process QMNC
QMNC started with pid=18, OS id=3504
Wed Feb 20 15:05:13 2013
Errors in file f:\oracle\product\10.2.0\admin\cksoltp\bdump\cksoltp_pmon_4064.trc:
ORA-00474: SMON process terminated with error

这个错误很明显是因为smon在回滚事务的时候，遇到异常从而出现ORA-00600[kghstack_free2]错误，使得数据库不能被正常open，通过分析trace文件发现回滚段36中有事务未提交，需要回滚，针对这样的数据库恢复方法很简单:1.屏蔽事务回滚，2.屏蔽回滚段强制offline等
1) EVENT=”10513 trace name context forever”
2）_offline_rollback_segments= _SYSSMU36$
数据库启动后，通过分析trace文件，找出来异常对象，然后重建该对象,除掉event/_offline_rollback_segments即可

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通过rowid获取segment header坏块数据

发表于 2013 年 2 月 19 日 由 惜分飞

在上篇(table中各种坏块对select/dml操作影响)中说到如果segment header异常了，不能通过ctas来获得相关数据，在群的讨论中，EZIO说到可以通过rowid方式来获得相关数据，通过测试证明，确实可以通过该方法获得数据，以后遇到此类错误，大家也不必惊慌.
创建测试表

SQL> create table t_xifenfei
  2  as
  3  select * from dba_objects where object_id is not null;


SQL> alter table t_xifenfei
  2  add constraint PK_t_xifenfei primary key (object_id)
  3  ;

Table altered.

SQL> alter system checkpoint;

System altered.

SQL> select count(*) from chf.t_xifenfei;

  COUNT(*)
----------
     74762

SQL> select header_file,header_block from 
  2  DBA_SEGments where segment_name='T_XIFENFEI' AND OWNER='CHF';

HEADER_FILE HEADER_BLOCK
----------- ------------
          4          170

dump block

alter system dump datafile 4 block 170;

Dump of buffer cache at level 4 for tsn=4 rdba=16777386
Block dump from disk:
buffer tsn: 4 rdba: 0x010000aa (4/170)
scn: 0x0b8c.3c0092e4 seq: 0x01 flg: 0x04 tail: 0x91e42301
frmt: 0x02 chkval: 0xa531 type: 0x23=PAGETABLE SEGMENT HEADER

通过header_block和dump block确定block 170即为PAGETABLE SEGMENT HEADER

bbed制造SEGMENT HEADER坏块

BBED> set block 170
        BLOCK#          170

BBED> set offset 8188
        OFFSET          8188

BBED> d
 File: /u01/oracle/oradata/ora11g/users01.dbf (0)
 Block: 170              Offsets: 8188 to 8191           Dba:0x00000000
------------------------------------------------------------------------
 0123e492 

 <32 bytes per line>

BBED> m /x 0123e491
Warning: contents of previous BIFILE will be lost. Proceed? (Y/N) y
 File: /u01/oracle/oradata/ora11g/users01.dbf (0)
 Block: 170              Offsets: 8188 to 8191           Dba:0x00000000
------------------------------------------------------------------------
 0123e491 

 <32 bytes per line>

BBED> sum apply 
Check value for File 0, Block 170:
current = 0xa531, required = 0xa531

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/users01.dbf
BLOCK = 170

Block 170 is corrupt
Corrupt block relative dba: 0x010000aa (file 0, block 170)
Fractured block found during verification
Data in bad block:
 type: 35 format: 2 rdba: 0x010000aa
 last change scn: 0x0b8c.3c0092e4 seq: 0x1 flg: 0x04
 spare1: 0x0 spare2: 0x0 spare3: 0x0
 consistency value in tail: 0x91e42301
 check value in block header: 0xa531
 computed block checksum: 0x0


DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 0
Total Blocks Failing   (Data) : 0
Total Blocks Processed (Index): 0
Total Blocks Failing   (Index): 0
Total Blocks Empty            : 0
Total Blocks Marked Corrupt   : 1
Total Blocks Influx           : 2
Message 531 not found;  product=RDBMS; facility=BBED

测试segment header坏块后select操作

SQL> select * from chf.t_xifenfei;
select * from chf.t_xifenfei
                         *
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 4, block # 170)
ORA-01110: data file 4: '/u01/oracle/oradata/ora11g/users01.dbf'

SQL> select /*+index(t PK_T_XIFENFEI)*/  count(rowid) from chf.t_xifenfei t;

COUNT(ROWID)
------------
       74762

基于rowid获取segment header 坏块对象数据

SQL> create table chf.bad_rows (table_name varchar2(60),
   2 row_id rowid, oracle_error_code number);

Table created.

SQL> DECLARE
  2   TYPE RowIDTab IS TABLE OF ROWID INDEX BY BINARY_INTEGER;
  3   CURSOR c1 IS  select /*+index(t PK_T_XIFENFEI)*/ rowid from chf.t_xifenfei t;
  4   r RowIDTab;
  5   rows  NATURAL := 20000;
  6   bad_rows number := 0 ;
  7   errors number;
  8   error_code number;
  9   myrowid rowid;
 10  BEGIN
 11   OPEN c1;
 12   LOOP
 13     FETCH  c1 BULK COLLECT INTO r LIMIT rows;
 14     EXIT WHEN r.count=0;
 15     BEGIN
 16      FORALL i IN r.FIRST..r.LAST SAVE EXCEPTIONS
 17       insert into chf.t_xifenfei_new
 18       select /*+ ROWID(A) */ *
 19       from chf.t_xifenfei A where rowid = r(i);
 20     EXCEPTION
 21     when OTHERS then
 22      BEGIN
 23       errors := SQL%BULK_EXCEPTIONS.COUNT;
 24       FOR err1 IN 1..errors LOOP
 25           error_code := SQL%BULK_EXCEPTIONS(err1).ERROR_CODE;
 26           myrowid := r(SQL%BULK_EXCEPTIONS(err1).ERROR_INDEX);
 27           bad_rows := bad_rows + 1;
 28           insert into chf.bad_rows values('chf.t_xifenfei',myrowid, error_code);
 29       END LOOP;
 30       END;
 31     END;
 32    commit;
 33   END LOOP;
 34   commit;
 35   CLOSE c1;
 36   dbms_output.put_line('Total Bad Rows: '||bad_rows);
 37  END;
 38  /
Total Bad Rows: 0

PL/SQL procedure successfully completed.

SQL> select count(*) from chf.t_xifenfei_new;

  COUNT(*)
----------
     74762

通过上面pl/sql，基于rowid成功获得segment header 异常对象中的所有数据记录.如果没有主键的表出现该问题,可以参考:使用plsql抢救数据

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