Monthly Archives: 八月 2012

bbed 删除 cluster table 记录

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对应cluster table使用bbed删除其中的部分记录,一直没有被攻克的难关,今天突发灵感,解决了cluster table 通过bbed删除记录后验证不能通过的难题.主要修改操作:oracle在index cluster中删除一条记录实际上只是把这条记录的行头由0x6c修改为0x7c,并且把这条记录所对应的聚簇键所在行的行头中记录的comc减1;修改验证信息
模拟cluster table 环境

SQL> create cluster clu_xff(id number(4));

Cluster created.

SQL> create table t_xifenfei
  2  (id number(4) 
  3  ,name      varchar2(25)
  4  )CLUSTER clu_xff (id);

Table created.

SQL> create index ind_clu_xff ON CLUSTER clu_xff;

Index created.

SQL> insert into t_xifenfei values(1,'xifenfei');

1 row created.

SQL> insert into t_xifenfei values(2,'www.orasos.com');

1 row created.

SQL> insert into t_xifenfei values(3,'XIFENFEI');

1 row created.

SQL> insert into t_xifenfei values(4,'WWW.XIFENFEI.COM');

1 row created.

SQL> insert into t_xifenfei values(2,'WWW.xifenfei.COM');

1 row created.

SQL> insert into t_xifenfei values(3,'XFF_CHF');

1 row created.

SQL> COMMIT;

Commit complete.

SQL> select t.*,
  2  dbms_rowid.rowid_relative_fno(rowid)||'_'||dbms_rowid.rowid_block_number(rowid) location 
  3  from t_xifenfei t;

        ID NAME                      LOCATION
---------- ------------------------- ----------
         2 www.orasos.com          4_171
         2 WWW.xifenfei.COM          4_171
         3 XIFENFEI                  4_172
         3 XFF_CHF                   4_172    <----需要删除记录
         4 WWW.XIFENFEI.COM          4_174
         1 xifenfei                  4_175

6 rows selected.

SQL> alter system checkpoint;

System altered.

SQL> conn / as sysdba
Connected.
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.

bbed删除记录操作

[oracle@xifenfei ~]$ bbed listfile=listfile mode=edit password=blockedit 

BBED: Release 2.0.0.0.0 - Limited Production on Thu Aug 9 09:33:58 2012

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

************* !!! For Oracle Internal Use only !!! ***************

BBED> set file 4 block 172
        FILE#           4
        BLOCK#          172

BBED> map
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 172                                   Dba:0x010000ac
------------------------------------------------------------
 KTB Data Block (Table/Cluster)

 struct kcbh, 20 bytes                      @0       

 struct ktbbh, 72 bytes                     @20      

 struct kdbh, 14 bytes                      @100     

 struct kdbt[2], 8 bytes                    @114     

 sb2 kdbr[3]                                @122     

 ub1 freespace[8013]                        @128     

 ub1 rowdata[47]                            @8141    

 ub4 tailchk                                @8188    

--查看该块的相关数据值
BBED> p kdbr
sb2 kdbr[0]                                 @122      8066
sb2 kdbr[1]                                 @124      8053
sb2 kdbr[2]                                 @126      8041

BBED> p *kdbr[0]
rowdata[25]
-----------
ub1 rowdata[25]                             @8166     0xac

BBED> x /rn
rowdata[25]                                 @8166    
-----------
flag@8166: 0xac (KDRHFL, KDRHFF, KDRHFH, KDRHFK)
lock@8167: 0x00
cols@8168:    1
kref@8169:    2
mref@8171:    2
hrid@8173:0x010000ac.0
nrid@8179:0x010000ac.0

col    0[2] @8185: 3 


BBED> p *kdbr[1]
rowdata[12]
-----------
ub1 rowdata[12]                             @8153     0x6c

BBED> x /rc
rowdata[12]                                 @8153    
-----------
flag@8153: 0x6c (KDRHFL, KDRHFF, KDRHFH, KDRHFC)
lock@8154: 0x00
cols@8155:    1

col    0[8] @8157: XIFENFEI


BBED> p *kdbr[2]
rowdata[0]
----------
ub1 rowdata[0]                              @8141     0x6c

BBED> x /rc
rowdata[0]                                  @8141    
----------
flag@8141: 0x6c (KDRHFL, KDRHFF, KDRHFH, KDRHFC)
lock@8142: 0x02
cols@8143:    1

col    0[7] @8145: XFF_CHF   <----需要删除记录


BBED> m /x 7c offset 8141
Warning: contents of previous BIFILE will be lost. Proceed? (Y/N) y
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 172              Offsets: 8141 to 8191           Dba:0x010000ac
------------------------------------------------------------------------
 7c020100 07584646 5f434846 6c000100 08584946 454e4645 49ac0001 02000200 
 010000ac 00000100 00ac0000 02c10402 066c1d 

 <32 bytes per line>

BBED> m /x 01 offset 8171
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 172              Offsets: 8171 to 8191           Dba:0x010000ac
------------------------------------------------------------------------
 01000100 00ac0000 010000ac 000002c1 0402066c 1d 

 <32 bytes per line>

BBED> p *kdbr[0]
rowdata[25]
-----------
ub1 rowdata[25]                             @8166     0xac

BBED> x /rn
rowdata[25]                                 @8166    
-----------
flag@8166: 0xac (KDRHFL, KDRHFF, KDRHFH, KDRHFK)
lock@8167: 0x00
cols@8168:    1
kref@8169:    2
mref@8171:    1
hrid@8173:0x010000ac.0
nrid@8179:0x010000ac.0

col    0[2] @8185: 3 

BBED> sum apply
Check value for File 4, Block 172:
current = 0x8f87, required = 0x8f87

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/users01.dbf
BLOCK = 172

Block Checking: DBA = 16777388, Block Type = KTB-managed data block
data header at 0xb53ed264
kdbchk: the amount of space used is not equal to block size   <----数据块使用空间错误
        used=67 fsc=0 avsp=8013 dtl=8088
Block 172 failed with check code 6110

DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 1
Total Blocks Failing   (Data) : 1
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> p kdbh
struct kdbh, 14 bytes                       @100     
   ub1 kdbhflag                             @100      0x00 (NONE)
   sb1 kdbhntab                             @101      2
   sb2 kdbhnrow                             @102      3
   sb2 kdbhfrre                             @104     -1
   sb2 kdbhfsbo                             @106      28
   sb2 kdbhfseo                             @108      8041
   sb2 kdbhavsp                             @110      8013
   sb2 kdbhtosp                             @112      8013

BBED> m /x 551f offset 110
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 172              Offsets:  110 to  126           Dba:0x010000ac
------------------------------------------------------------------------
 551f4d1f 00000100 01000200 821f751f  

 <32 bytes per line>

BBED>  p kdbh
struct kdbh, 14 bytes                       @100     
   ub1 kdbhflag                             @100      0x00 (NONE)
   sb1 kdbhntab                             @101      2
   sb2 kdbhnrow                             @102      3
   sb2 kdbhfrre                             @104     -1
   sb2 kdbhfsbo                             @106      28
   sb2 kdbhfseo                             @108      8041
   sb2 kdbhavsp                             @110      8021
   sb2 kdbhtosp                             @112      8013

BBED> sum apply
Check value for File 4, Block 172:
current = 0x8f9f, required = 0x8f9f

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/users01.dbf
BLOCK = 172

Block Checking: DBA = 16777388, Block Type = KTB-managed data block
data header at 0xb53ed264
kdbchk: avsp(8021) > tosp(8013)           <----avsp 不能大于tosp
Block 172 failed with check code 6128

DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 1
Total Blocks Failing   (Data) : 1
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>  m /x 551f offset 112     
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 172              Offsets:  112 to  128           Dba:0x010000ac
------------------------------------------------------------------------
 551f0000 01000100 0200821f 751f691f 

 <32 bytes per line>

BBED> sum apply
Check value for File 4, Block 172:
current = 0x8f87, required = 0x8f87

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/users01.dbf
BLOCK = 172

Block Checking: DBA = 16777388, Block Type = KTB-managed data block
data header at 0xb53ed264
kdbchk: space available on commit is incorrect
        tosp=8021 fsc=0 stb=4 avsp=8021        <----tosp值不合适
Block 172 failed with check code 6111

DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 1
Total Blocks Failing   (Data) : 1
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> set count 64
        COUNT           64

BBED> m /x 591f offset 112
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 172              Offsets:  112 to  175           Dba:0x010000ac
------------------------------------------------------------------------
 591f0000 01000100 0200821f 751f691f 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>

BBED> sum apply
Check value for File 4, Block 172:
current = 0x8f8b, required = 0x8f8b

--修改块工作完成
BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/users01.dbf
BLOCK = 172


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

启动库验证

SQL> startup
ORACLE instance started.

Total System Global Area  313860096 bytes
Fixed Size                  1344652 bytes
Variable Size             260049780 bytes
Database Buffers           46137344 bytes
Redo Buffers                6328320 bytes
Database mounted.
Database opened.
SQL> conn chf/xifenfei
Connected.
SQL> select * from t_xifenfei;

        ID NAME
---------- -------------------------
         2 www.orasos.com
         2 WWW.xifenfei.COM
         3 XIFENFEI
         4 WWW.XIFENFEI.COM
         1 xifenfei
--XFF_CHF记录被删除

SQL> insert into t_xifenfei values(3,'惜分飞');

1 row created.

SQL> delete from t_xifenfei where name='XIFENFEI';

1 row deleted.

SQL> commit;

Commit complete.

SQL> select * from t_xifenfei;

        ID NAME
---------- -------------------------
         2 www.orasos.com
         2 WWW.xifenfei.COM
         3 惜分飞
         4 WWW.XIFENFEI.COM
         1 xifenfei
--证明XFF_CHF所在数据块其他dml操作正常,证明修改正确

bbed 恢复 GLOBAL_NAME 为空故障

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看到dbsnake关于UPDATE GLOBAL_NAME为空之后的恢复写的不是很完整,自己通过试验和对bbed的研究,完善他的blog内容(泄露一点内部的东西)
模拟错误

SQL> select * from v$version;

BANNER
------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - Production
PL/SQL Release 11.2.0.3.0 - Production
CORE    11.2.0.3.0      Production
TNS for Linux: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production

SQL> select * from global_name ;

GLOBAL_NAME
--------------------------------------------------------------------
ORA11G

SQL> update global_name set global_name='';

1 row updated.

SQL> COMMIT;

Commit complete.

SQL> SHUTDOWN IMMEDIATE
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> STARTUP
ORACLE instance started.

Total System Global Area  313860096 bytes
Fixed Size                  1344652 bytes
Variable Size             260049780 bytes
Database Buffers           46137344 bytes
Redo Buffers                6328320 bytes
Database mounted.
ORA-01092: ORACLE instance terminated. Disconnection forced
ORA-00600: internal error code, arguments: [18062], [], [], [], [], [], [], [],
[], [], [], []
Process ID: 28306
Session ID: 125 Serial number: 5

alert日志

Errors in file /u01/oracle/diag/rdbms/ora11g/ora11g/trace/ora11g_ora_28306.trc  (incident=20556):
ORA-00600: internal error code, arguments: [18062], [], [], [], [], [], [], [], [], [], [], []
Incident details in: /u01/oracle/diag/rdbms/ora11g/ora11g/incident/incdir_20556/ora11g_ora_28306_i20556.trc
Wed Aug 08 23:21:48 2012
Use ADRCI or Support Workbench to package the incident.
See Note 411.1 at My Oracle Support for error and packaging details.
Errors in file /u01/oracle/diag/rdbms/ora11g/ora11g/trace/ora11g_ora_28306.trc:
ORA-00600: internal error code, arguments: [18062], [], [], [], [], [], [], [], [], [], [], []
Errors in file /u01/oracle/diag/rdbms/ora11g/ora11g/trace/ora11g_ora_28306.trc:
ORA-00600: internal error code, arguments: [18062], [], [], [], [], [], [], [], [], [], [], []
Error 600 happened during db open, shutting down database
USER (ospid: 28306): terminating the instance due to error 600
Instance terminated by USER, pid = 28306
ORA-1092 signalled during: ALTER DATABASE OPEN...
opiodr aborting process unknown ospid (28306) as a result of ORA-1092
Wed Aug 08 23:21:48 2012
ORA-1092 : opitsk aborting process

找出global_name相关信息(另外库中)

SQL> SET LONG 1000
SQL> select dbms_metadata.get_ddl('VIEW','GLOBAL_NAME','SYS') from dual;

DBMS_METADATA.GET_DDL('VIEW','GLOBAL_NAME','SYS')
--------------------------------------------------------------------------------

  CREATE OR REPLACE FORCE VIEW "SYS"."GLOBAL_NAME" ("GLOBAL_NAME") AS
  select value$ from sys.props$ where name = 'GLOBAL_DB_NAME'

SQL> select * from props$ where value$='XIFENFEI';

NAME                           VALUE$
------------------------------ ----------------------------------------
COMMENT$
--------------------------------------------------------------------------
GLOBAL_DB_NAME                 XIFENFEI
Global database name

SQL> select dump('GLOBAL_DB_NAME','16') from dual;

DUMP('GLOBAL_DB_NAME','16')
--------------------------------------------------------
Typ=96 Len=14: 47,4c,4f,42,41,4c,5f,44,42,5f,4e,41,4d,45
--得出GLOBAL_DB_NAME存储字16进制字符串为:0e474c4f42414c5f44425f4e414d45

bbed操作

--通过第三方工具定位props$表中的GLOBAL_DB_NAME列在数据块0x00400321的31行上

[oracle@xifenfei ~]$ bbed listfile=listfile mode=edit password=blockedit

BBED: Release 2.0.0.0.0 - Limited Production on Thu Aug 9 00:26:12 2012

Copyright (c) 1982, 2007, Oracle.  All rights reserved.

************* !!! For Oracle Internal Use only !!! ***************

BBED> info
 File#  Name                                                        Size(blks)
 -----  ----                                                        ----------
     1  /u01/oracle/oradata/ora11g/system01.dbf                              0
     2  /u01/oracle/oradata/ora11g/sysaux01.dbf                              0
     3  /u01/oracle/oradata/ora11g/undotbs01.dbf                             0
     4  /u01/oracle/oradata/ora11g/users01.dbf                               0

BBED> set block 801
        BLOCK#          801

BBED> map
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801                                   Dba:0x00400321
------------------------------------------------------------
 KTB Data Block (Table/Cluster)

 struct kcbh, 20 bytes                      @0       

 struct ktbbh, 72 bytes                     @20      

 struct kdbh, 14 bytes                      @92      

 struct kdbt[1], 4 bytes                    @106     

 sb2 kdbr[37]                               @110     

 ub1 freespace[5771]                        @184     

 ub1 rowdata[2233]                          @5955    

 ub4 tailchk                                @8188    

BBED>  p *kdbr[31]
rowdata[0]
----------
ub1 rowdata[0]                              @5955     0x2c

BBED> x /rccc
rowdata[0]                                  @5955    
----------
flag@5955: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@5956: 0x02
cols@5957:    3

col   0[14] @5958: GLOBAL_DB_NAME
col    1[0] @5973: *NULL*
col   2[20] @5974: Global database name

BBED> set count 64
        COUNT           64

BBED> f /x 0e474c4f
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets: 5958 to 6021           Dba:0x00400321
------------------------------------------------------------------------
 0e474c4f 42414c5f 44425f4e 414d45ff 14476c6f 62616c20 64617461 62617365 
 206e616d 652c0003 0e474c4f 42414c5f 44425f4e 414d4506 4f524131 31471447 

 <32 bytes per line>

BBED> f
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets: 5998 to 6061           Dba:0x00400321
------------------------------------------------------------------------
 0e474c4f 42414c5f 44425f4e 414d4506 4f524131 31471447 6c6f6261 6c206461 
 74616261 7365206e 616d652c 00030a44 4254494d 455a4f4e 45053030 3a30300c 

 <32 bytes per line>

BBED> f
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets: 6460 to 6523           Dba:0x00400321
------------------------------------------------------------------------
 0e474c4f 42414c5f 44425f4e 414d4508 53454544 44415441 14476c6f 62616c20 
 64617461 62617365 206e616d 652c0003 114e4c53 5f524442 4d535f56 45525349 

 <32 bytes per line>

BBED> f
BBED-00212: search string not found

BBED> d /v offset 5958
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801     Offsets: 5958 to 6021  Dba:0x00400321
-------------------------------------------------------
 0e474c4f 42414c5f 44425f4e 414d45ff l .GLOBAL_DB_NAME.
 14476c6f 62616c20 64617461 62617365 l .Global database
 206e616d 652c0003 0e474c4f 42414c5f l  name,...GLOBAL_
 44425f4e 414d4506 4f524131 31471447 l DB_NAME.ORA11G.G

 <16 bytes per line>

BBED> d /v offset 5998
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801     Offsets: 5998 to 6061  Dba:0x00400321
-------------------------------------------------------
 0e474c4f 42414c5f 44425f4e 414d4506 l .GLOBAL_DB_NAME.
 4f524131 31471447 6c6f6261 6c206461 l ORA11G.Global da
 74616261 7365206e 616d652c 00030a44 l tabase name,...D
 4254494d 455a4f4e 45053030 3a30300c l BTIMEZONE.00:00.

 <16 bytes per line>

BBED> d /v offset 6460
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801     Offsets: 6460 to 6523  Dba:0x00400321
-------------------------------------------------------
 0e474c4f 42414c5f 44425f4e 414d4508 l .GLOBAL_DB_NAME.
 53454544 44415441 14476c6f 62616c20 l SEEDDATA.Global 
 64617461 62617365 206e616d 652c0003 l database name,..
 114e4c53 5f524442 4d535f56 45525349 l .NLS_RDBMS_VERSI

 <16 bytes per line>
--通过时上面的查找可以知道数据库对GLOBAL_DB_NAME有进行两次update操作
--GLOBAL_DB_NAME初始化值SEEDDATA,第一次更新为ORA11G,第二次更新为null

BBED> p  kdbr[31]
sb2 kdbr[31]                                @172      5863
--这里可以发现我们看到offset 5995开始有值,但是row directory却指向了5863

BBED> d offset 5863 count 128
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets: 5863 to 5990           Dba:0x00400321
------------------------------------------------------------------------
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 2c02030e 
 474c4f42 414c5f44 425f4e41 4d45ff14 476c6f62 616c2064 61746162 61736520 

 <32 bytes per line>
--通过dump看到row directory指向的值和实际的数据相差(5995-5863),都是0

BBED> d /v offset 5900
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801     Offsets: 5900 to 6027  Dba:0x00400321
-------------------------------------------------------
 00000000 00000000 00000000 00000000 l ................
 00000000 00000000 00000000 00000000 l ................
 00000000 00000000 00000000 00000000 l ................
 00000000 0000002c 02030e47 4c4f4241 l .......,...GLOBA
 4c5f4442 5f4e414d 45ff1447 6c6f6261 l L_DB_NAME..Globa
 6c206461 74616261 7365206e 616d652c l l database name,
 00030e47 4c4f4241 4c5f4442 5f4e414d l ...GLOBAL_DB_NAM
 45064f52 41313147 14476c6f 62616c20 l E.ORA11G.Global 

 <16 bytes per line>
--需要指定的新值前面也存在同样的0,所以模仿的处理方法,让row directory同样向前偏移92

BBED> m /x 0f17 offset 172
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets:  172 to  299           Dba:0x00400321
------------------------------------------------------------------------
 0f176018 16189a17 5e173d17 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>

BBED> p kdbr[31]
sb2 kdbr[31]                                @172      5903

BBED> p *kdbr[31]
rowdata[40]
-----------
ub1 rowdata[40]                             @5995     0x2c

BBED> x /rccc
rowdata[40]                                 @5995    
-----------
flag@5995: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@5996: 0x00
cols@5997:    3

col   0[14] @5998: GLOBAL_DB_NAME
col    1[6] @6013: ORA11G
col   2[20] @6020: Global database name

修改lock信息
BBED> m /x 02 offset 5996
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets: 5996 to 6123           Dba:0x00400321
------------------------------------------------------------------------
 02030e47 4c4f4241 4c5f4442 5f4e414d 45064f52 41313147 14476c6f 62616c20 
 64617461 62617365 206e616d 652c0003 0a444254 494d455a 4f4e4505 30303a30 
 300c4442 2074696d 65207a6f 6e652c00 02174e4f 5f555345 5249445f 56455249 
 46494552 5f53414c 54203633 39364335 38414231 37414530 30374539 41373238 

 <32 bytes per line>

BBED> d offset 5955
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets: 5955 to 6082           Dba:0x00400321
------------------------------------------------------------------------
 2c02030e 474c4f42 414c5f44 425f4e41 4d45ff14 476c6f62 616c2064 61746162 
 61736520 6e616d65 2c02030e 474c4f42 414c5f44 425f4e41 4d45064f 52413131 
 4714476c 6f62616c 20646174 61626173 65206e61 6d652c00 030a4442 54494d45 
 5a4f4e45 0530303a 30300c44 42207469 6d65207a 6f6e652c 0002174e 4f5f5553 

 <32 bytes per line>

BBED> m /x 2c00  
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets: 5955 to 6082           Dba:0x00400321
------------------------------------------------------------------------
 2c00030e 474c4f42 414c5f44 425f4e41 4d45ff14 476c6f62 616c2064 61746162 
 61736520 6e616d65 2c02030e 474c4f42 414c5f44 425f4e41 4d45064f 52413131 
 4714476c 6f62616c 20646174 61626173 65206e61 6d652c00 030a4442 54494d45 
 5a4f4e45 0530303a 30300c44 42207469 6d65207a 6f6e652c 0002174e 4f5f5553 

 <32 bytes per line>

--验证块
BBED> sum apply
Check value for File 1, Block 801:
current = 0xe836, required = 0xe836

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/system01.dbf
BLOCK = 801

Block Checking: DBA = 4195105, Block Type = KTB-managed data block
data header at 0xb677b25c
kdbchk: the amount of space used is not equal to block size
        used=2056 fsc=6 avsp=6040 dtl=8096
Block 801 failed with check code 6110

DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 1
Total Blocks Failing   (Data) : 1
Total Blocks Processed (Index): 0
Total Blocks Failing   (Index): 0
Total Blocks Empty            : 0
Total Blocks Marked Corrupt   : 0
Total Blocks Influx           : 0

--修改_ktbitfsc信息，让其通过块验证
BBED> p ktbbhitl
struct ktbbhitl[0], 24 bytes                @44      
   struct ktbitxid, 8 bytes                 @44      
      ub2 kxidusn                           @44       0x0004
      ub2 kxidslt                           @46       0x000e
      ub4 kxidsqn                           @48       0x000001d4
   struct ktbituba, 8 bytes                 @52      
      ub4 kubadba                           @52       0x00c00a93
      ub2 kubaseq                           @56       0x0083
      ub1 kubarec                           @58       0x33
   ub2 ktbitflg                             @60       0x8000 (KTBFCOM)
   union _ktbitun, 2 bytes                  @62      
      b2 _ktbitfsc                          @62       0
      ub2 _ktbitwrp                         @62       0x0000
   ub4 ktbitbas                             @64       0x000c78fe
struct ktbbhitl[1], 24 bytes                @68      
   struct ktbitxid, 8 bytes                 @68      
      ub2 kxidusn                           @68       0x000a
      ub2 kxidslt                           @70       0x0016
      ub4 kxidsqn                           @72       0x000001eb
   struct ktbituba, 8 bytes                 @76      
      ub4 kubadba                           @76       0x00c0015b
      ub2 kubaseq                           @80       0x008f
      ub1 kubarec                           @82       0x0d
   ub2 ktbitflg                             @84       0x0001 (NONE)
   union _ktbitun, 2 bytes                  @86      
      b2 _ktbitfsc                          @86       6
      ub2 _ktbitwrp                         @86       0x0006
   ub4 ktbitbas                             @88       0x00000000

BBED> m /x 00 offset 86
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets:   86 to  213           Dba:0x00400321
------------------------------------------------------------------------
 00000000 00000001 25000600 5c00e716 98179e17 00002500 701f571e 92189c1e 
 101efb1d ffff981d 551d0f1d d91cb71c 941c731c 4a1c1a1c ef1bc51b 9c1b701b 
 471b191b d61a931a 3c1a101a ee19bc19 86194e19 0d190f17 60181618 9a175e17 
 3d170000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>

BBED> sum apply
Check value for File 1, Block 801:
current = 0xe830, required = 0xe830

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/system01.dbf
BLOCK = 801

Block Checking: DBA = 4195105, Block Type = KTB-managed data block
data header at 0xb677b25c
kdbchk: space available on commit is incorrect
        tosp=6046 fsc=0 stb=0 avsp=6040
Block 801 failed with check code 6111

DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 1
Total Blocks Failing   (Data) : 1
Total Blocks Processed (Index): 0
Total Blocks Failing   (Index): 0
Total Blocks Empty            : 0
Total Blocks Marked Corrupt   : 0
Total Blocks Influx           : 0

--修改kdbhtosp信息
BBED> p kdbh
struct kdbh, 14 bytes                       @92      
   ub1 kdbhflag                             @92       0x00 (NONE)
   b1 kdbhntab                              @93       1
   b2 kdbhnrow                              @94       37
   sb2 kdbhfrre                             @96       6
   sb2 kdbhfsbo                             @98       92
   sb2 kdbhfseo                             @100      5863
   b2 kdbhavsp                              @102      6040
   b2 kdbhtosp                              @104      6046

BBED> d offset 102
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets:  102 to  229           Dba:0x00400321
------------------------------------------------------------------------
 98179e17 00002500 701f571e 92189c1e 101efb1d ffff981d 551d0f1d d91cb71c 
 941c731c 4a1c1a1c ef1bc51b 9c1b701b 471b191b d61a931a 3c1a101a ee19bc19 
 86194e19 0d190f17 60181618 9a175e17 3d170000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>

BBED> d offset 104
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets:  104 to  231           Dba:0x00400321
------------------------------------------------------------------------
 9e170000 2500701f 571e9218 9c1e101e fb1dffff 981d551d 0f1dd91c b71c941c 
 731c4a1c 1a1cef1b c51b9c1b 701b471b 191bd61a 931a3c1a 101aee19 bc198619 
 4e190d19 0f176018 16189a17 5e173d17 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>

BBED> m /x 98
 File: /u01/oracle/oradata/ora11g/system01.dbf (1)
 Block: 801              Offsets:  104 to  231           Dba:0x00400321
------------------------------------------------------------------------
 98170000 2500701f 571e9218 9c1e101e fb1dffff 981d551d 0f1dd91c b71c941c 
 731c4a1c 1a1cef1b c51b9c1b 701b471b 191bd61a 931a3c1a 101aee19 bc198619 
 4e190d19 0f176018 16189a17 5e173d17 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>

--至此修改row directory指针完成
BBED> sum apply
Check value for File 1, Block 801:
current = 0xe836, required = 0xe836

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/system01.dbf
BLOCK = 801


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

重新启动数据库

SQL> startup 
ORACLE instance started.

Total System Global Area  313860096 bytes
Fixed Size                  1344652 bytes
Variable Size             260049780 bytes
Database Buffers           46137344 bytes
Redo Buffers                6328320 bytes
Database mounted.
Database opened.
SQL> select * from global_name ;

GLOBAL_NAME
--------------------------------------------------------
ORA11G

SQL>

利用bbed找回ORACLE更新前值

Posted on by

模拟数据块更新

SQL> create table t_xifenfei(id number,name varchar2(10));

Table created.

SQL> insert into t_xifenfei values(1,'XFF');

1 row created.

SQL> insert into t_xifenfei values(2,'CHF');

1 row created.

SQL> commit; 

Commit complete.

SQL> alter system checkpoint;

System altered.

SQL> select id,rowid,
  2  dbms_rowid.rowid_relative_fno(rowid)rel_fno,
  3  dbms_rowid.rowid_block_number(rowid)blockno,
  4  dbms_rowid.rowid_row_number(rowid) rowno
  5  from t_xifenfei;

        ID ROWID                 REL_FNO    BLOCKNO      ROWNO
---------- ------------------ ---------- ---------- ----------
         1 AAASc+AAEAAAACvAAA          4        175          0
         2 AAASc+AAEAAAACvAAB          4        175          1

SQL> select dump(1,'16') from dual;

DUMP(1,'16')
-----------------
Typ=2 Len=2: c1,2

SQL> select dump(2,'16') from dual;

DUMP(2,'16')
-----------------
Typ=2 Len=2: c1,3

SQL> select dump('XFF','16') FROM DUAL;

DUMP('XFF','16')
----------------------
Typ=96 Len=3: 58,46,46

SQL> SELECT DUMP('CHF','16') FROM DUAL;

DUMP('CHF','16')
----------------------
Typ=96 Len=3: 43,48,46

SQL> update t_xifenfei set name='XIFENFEI' where id=1;

1 row updated.

SQL> commit;

Commit complete.

SQL> select dump('XIFENFEI','16') from dual;

DUMP('XIFENFEI','16')
-------------------------------------
Typ=96 Len=8: 58,49,46,45,4e,46,45,49

SQL> alter system checkpoint;

System altered.

SQL> select * from t_xifenfei;

        ID NAME
---------- ----------
         1 XIFENFEI
         2 CHF

这里我们对数据库进行了一次更新操作,并且dump出来对应值,为了方便定位到相应记录

bbed查看相关值

[oracle@xifenfei ~]$ bbed listfile=listfile mode=edit password=blockedit

BBED: Release 2.0.0.0.0 - Limited Production on Wed Aug 8 20:50:47 2012

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

************* !!! For Oracle Internal Use only !!! ***************

BBED> set file 4 block 175
        FILE#           4
        BLOCK#          175

BBED> map
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175                                   Dba:0x010000af
------------------------------------------------------------
 KTB Data Block (Table/Cluster)

 struct kcbh, 20 bytes                      @0       

 struct ktbbh, 72 bytes                     @20      

 struct kdbh, 14 bytes                      @100     

 struct kdbt[1], 4 bytes                    @114     

 sb2 kdbr[2]                                @118     

 ub1 freespace[8031]                        @122     

 ub1 rowdata[35]                            @8153    

 ub4 tailchk                                @8188 

BBED> p kdbr
sb2 kdbr[0]                                 @118      8053
sb2 kdbr[1]                                 @120      8068

BBED> p *kdbr[1]
rowdata[15]
-----------
ub1 rowdata[15]                             @8168     0x2c

BBED> x /rnc
rowdata[15]                                 @8168    
-----------
flag@8168: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@8169: 0x00
cols@8170:    2

col    0[2] @8171: 2 
col    1[3] @8174: CHF

BBED> p *kdbr[0]
rowdata[0]
----------
ub1 rowdata[0]                              @8153     0x2c

BBED> x /rnc
rowdata[0]                                  @8153    
----------
flag@8153: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@8154: 0x02
cols@8155:    2

col    0[2] @8156: 1 
col    1[8] @8159: XIFENFEI

BBED> set count 64
        COUNT           64

 <32 bytes per line>

BBED> d /v
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175     Offsets: 8153 to 8191  Dba:0x010000af
-------------------------------------------------------
 2c020202 c1020858 4946454e 4645492c l ,......XIFENFEI,
 000202c1 03034348 462c0002 02c10203 l ......CHF,......
 58464602 068de8                     l XFF....

 <16 bytes per line>

使用bbed找回历史值

--准备工作,通过dump出来的值,推算出来第一条记录的起点02c10203584646,
--在这个值的基础上offset-3得到offset值为8078

BBED> p kdbr
sb2 kdbr[0]                                 @118      8053
sb2 kdbr[1]                                 @120      8068

--修改row directory指针位置
BBED> m /x 8e1f
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175              Offsets:  118 to  181           Dba:0x010000af
------------------------------------------------------------------------
 8e1f841f 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>

BBED> p kdbr
sb2 kdbr[0]                                 @118      8078
sb2 kdbr[1]                                 @120      8068

BBED> sum apply
Check value for File 4, Block 175:
current = 0xdff8, required = 0xdff8

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/users01.dbf
BLOCK = 175

Block Checking: DBA = 16777391, Block Type = KTB-managed data block
data header at 0xb53cd264
kdbchk: xaction header lock count mismatch
        trans=2 ilk=1 nlo=0     --提示事务锁错误
Block 175 failed with check code 6108

DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 1
Total Blocks Failing   (Data) : 1
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> p *kdbr[0] 
rowdata[25]
-----------
ub1 rowdata[25]                             @8178     0x2c

BBED> d
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175              Offsets: 8178 to 8191           Dba:0x010000af
------------------------------------------------------------------------
 2c000202 c1020358 46460206 8de8 

 <32 bytes per line>

BBED> x /rnc
rowdata[25]                                 @8178    
-----------
flag@8178: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@8179: 0x00  --被更新前的记录事务锁标识为0,而更新后的事务锁标识为2
cols@8180:    2

col    0[2] @8181: 1 
col    1[3] @8184: XFF

--修改事务锁标识为2
BBED> m /x 02 offset 8179
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175              Offsets: 8179 to 8191           Dba:0x010000af
------------------------------------------------------------------------
 020202c1 02035846 4602068d e8 

 <32 bytes per line>

BBED> set offset 8153
        OFFSET          8153

BBED> d
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175              Offsets: 8153 to 8191           Dba:0x010000af
------------------------------------------------------------------------
 2c020202 c1020858 4946454e 4645492c 000202c1 03034348 462c0202 02c10203 
 58464602 068de8 

 <32 bytes per line>

--把更新后值的事务锁标识改为0
BBED> m /x 00 offset +1
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175              Offsets: 8154 to 8191           Dba:0x010000af
------------------------------------------------------------------------
 000202c1 02085849 46454e46 45492c00 0202c103 03434846 2c020202 c1020358 
 46460206 8de8 

 <32 bytes per line>

BBED> sum apply
Check value for File 4, Block 175:
current = 0xddfa, required = 0xddfa

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/users01.dbf
BLOCK = 175

Block Checking: DBA = 16777391, Block Type = KTB-managed data block
data header at 0xb53cd264
kdbchk: the amount of space used is not equal to block size
        used=42 fsc=0 avsp=8041 dtl=8088   -->提示块的空间使用不正确
Block 175 failed with check code 6110

DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 1
Total Blocks Failing   (Data) : 1
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> p ktbbh
struct ktbbh, 72 bytes                      @20      
   ub1 ktbbhtyp                             @20       0x01 (KDDBTDATA)
   union ktbbhsid, 4 bytes                  @24      
      ub4 ktbbhsg1                          @24       0x0001273e
      ub4 ktbbhod1                          @24       0x0001273e
   struct ktbbhcsc, 8 bytes                 @28      
      ub4 kscnbas                           @28       0x0000e88a
      ub2 kscnwrp                           @32       0x0002
   sb2 ktbbhict                             @36       2
   ub1 ktbbhflg                             @38       0x32 (NONE)
   ub1 ktbbhfsl                             @39       0x00
   ub4 ktbbhfnx                             @40       0x010000a8
   struct ktbbhitl[0], 24 bytes             @44      
      struct ktbitxid, 8 bytes              @44      
         ub2 kxidusn                        @44       0x0006
         ub2 kxidslt                        @46       0x001e
         ub4 kxidsqn                        @48       0x000002c6
      struct ktbituba, 8 bytes              @52      
         ub4 kubadba                        @52       0x00c000d9
         ub2 kubaseq                        @56       0x0086
         ub1 kubarec                        @58       0x2a
      ub2 ktbitflg                          @60       0x8000 (KTBFCOM)
      union _ktbitun, 2 bytes               @62      
         sb2 _ktbitfsc                      @62       2   
         ub2 _ktbitwrp                      @62       0x0002
      ub4 ktbitbas                          @64       0x0000e550
   struct ktbbhitl[1], 24 bytes             @68      
      struct ktbitxid, 8 bytes              @68      
         ub2 kxidusn                        @68       0x0006
         ub2 kxidslt                        @70       0x0008
         ub4 kxidsqn                        @72       0x000002c7
      struct ktbituba, 8 bytes              @76      
         ub4 kubadba                        @76       0x00c000da
         ub2 kubaseq                        @80       0x0086
         ub1 kubarec                        @82       0x12
      ub2 ktbitflg                          @84       0x2001 (KTBFUPB)
      union _ktbitun, 2 bytes               @86      
         sb2 _ktbitfsc                      @86       0
         ub2 _ktbitwrp                      @86       0x0000
      ub4 ktbitbas                          @88       0x0000e88d

--所有的_ktbitfsc修改为0
BBED> m /x 00 offset 62
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175              Offsets:   62 to  125           Dba:0x010000af
------------------------------------------------------------------------
 000050e5 00000600 0800c702 0000da00 c0008600 12000120 00008de8 00000000 
 00000000 00000001 0200ffff 1600751f 691f691f 00000200 8e1f841f 00000000 

 <32 bytes per line>

BBED> sum apply
Check value for File 4, Block 175:
current = 0xddf8, required = 0xddf8

BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/users01.dbf
BLOCK = 175

Block Checking: DBA = 16777391, Block Type = KTB-managed data block
data header at 0xb53cd264
kdbchk: the amount of space used is not equal to block size
        used=42 fsc=0 avsp=8041 dtl=8088
Block 175 failed with check code 6110

DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 1
Total Blocks Failing   (Data) : 1
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> p kdbh
struct kdbh, 14 bytes                       @100     
   ub1 kdbhflag                             @100      0x00 (NONE)
   sb1 kdbhntab                             @101      1
   sb2 kdbhnrow                             @102      2
   sb2 kdbhfrre                             @104     -1
   sb2 kdbhfsbo                             @106      22
   sb2 kdbhfseo                             @108      8053
   sb2 kdbhavsp                             @110      8045
   sb2 kdbhtosp                             @112      8045

--修改kdbhtosp和kdbhavsp值
BBED>  m /x 6e1f  offset 112
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175              Offsets:  112 to  175           Dba:0x010000af
------------------------------------------------------------------------
 6e1f0000 02008e1f 841f0000 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>

BBED> m /x  6e1f  offset 110
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175              Offsets:  110 to  173           Dba:0x010000af
------------------------------------------------------------------------
 6e1f6e1f 00000200 8e1f841f 00000000 00000000 00000000 00000000 00000000 
 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 

 <32 bytes per line>

BBED> sum apply
Check value for File 4, Block 175:
current = 0xddf8, required = 0xddf8

--数据块验证通过
BBED> verify
DBVERIFY - Verification starting
FILE = /u01/oracle/oradata/ora11g/users01.dbf
BLOCK = 175


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

重启数据库

SQL> shutdown abort
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area  313860096 bytes
Fixed Size                  1344652 bytes
Variable Size             251661172 bytes
Database Buffers           54525952 bytes
Redo Buffers                6328320 bytes
Database mounted.
Database opened.

--找回更新前值
SQL> select * from chf.t_xifenfei;

        ID NAME
---------- ----------
         1 XFF
         2 CHF

ORACLE update 操作内部原理

Posted on by

对于oracle的update操作,在数据块中具体是如何出来,是直接更新原来值,还是通过插入新值修改指针的方法实现.下面通过证明:
模拟表插入数据

SQL> create table t_xifenfei(id number,name varchar2(10));

Table created.

SQL> insert into t_xifenfei values(1,'XFF');

1 row created.

SQL> insert into t_xifenfei values(2,'CHF');

1 row created.

SQL> commit; 

Commit complete.

SQL> alter system checkpoint;

System altered.

SQL> select id,rowid,
  2  dbms_rowid.rowid_relative_fno(rowid)rel_fno,
  3  dbms_rowid.rowid_block_number(rowid)blockno,
  4  dbms_rowid.rowid_row_number(rowid) rowno
  5  from t_xifenfei;

        ID ROWID                 REL_FNO    BLOCKNO      ROWNO
---------- ------------------ ---------- ---------- ----------
         1 AAASc+AAEAAAACvAAA          4        175          0
         2 AAASc+AAEAAAACvAAB          4        175          1

SQL> alter system dump datafile 4 block 175;

System altered.

SQL>  select value from v$diag_info where name='Default Trace File';

VALUE
--------------------------------------------------------------------------------
/u01/oracle/diag/rdbms/ora11g/ora11g/trace/ora11g_ora_24625.trc

数据存储对应16进制值

SQL> select dump(1,'16') from dual;

DUMP(1,'16')
-----------------
Typ=2 Len=2: c1,2

SQL> select dump(2,'16') from dual;

DUMP(2,'16')
-----------------
Typ=2 Len=2: c1,3

SQL> select dump('XFF','16') FROM DUAL;

DUMP('XFF','16')
----------------------
Typ=96 Len=3: 58,46,46

SQL> SELECT DUMP('CHF','16') FROM DUAL;

DUMP('CHF','16')
----------------------
Typ=96 Len=3: 43,48,46

得出第一条记录对应值为:02c10203584646;第二条记录对应值为:02c10303434846

dump 数据块得到记录

bdba: 0x010000af
data_block_dump,data header at 0xb683c064
===============
tsiz: 0x1f98
hsiz: 0x16
pbl: 0xb683c064
     76543210
flag=--------
ntab=1
nrow=2
frre=-1
fsbo=0x16
fseo=0x1f84
avsp=0x1f6e
tosp=0x1f6e
0xe:pti[0]      nrow=2  offs=0
0x12:pri[0]     offs=0x1f8e    ---->8078
0x14:pri[1]     offs=0x1f84    ---->8068
block_row_dump:
tab 0, row 0, @0x1f8e
tl: 10 fb: --H-FL-- lb: 0x1  cc: 2
col  0: [ 2]  c1 02
col  1: [ 3]  58 46 46
tab 0, row 1, @0x1f84
tl: 10 fb: --H-FL-- lb: 0x1  cc: 2
col  0: [ 2]  c1 03
col  1: [ 3]  43 48 46
end_of_block_dump
End dump data blocks tsn: 4 file#: 4 minblk 175 maxblk 175

bbed查看相关记录

BBED> p kdbr
sb2 kdbr[0]                                 @118      8078 <--第一条row directory指针位置
sb2 kdbr[1]                                 @120      8068 <--第二条row directory指针位置

BBED> p *kdbr[0] 
rowdata[10]
-----------
ub1 rowdata[10]                             @8178     0x2c

BBED> x /rnc  
rowdata[10]                                 @8178    
-----------
flag@8178: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@8179: 0x01
cols@8180:    2

col    0[2] @8181: 1 
col    1[3] @8184: XFF


BBED> p *kdbr[1]
rowdata[0]
----------
ub1 rowdata[0]                              @8168     0x2c

BBED> x /rnc
rowdata[0]                                  @8168    
----------
flag@8168: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@8169: 0x01
cols@8170:    2

col    0[2] @8171: 2 
col    1[3] @8174: CHF


BBED> d
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175              Offsets: 8168 to 8191           Dba:0x010000af
------------------------------------------------------------------------
 2c010202 c1030343 48462c01 0202c102 03584646 010650e5 

 <32 bytes per line>

这里可以得到结论如下:
1.数据是从块的底部开始往上存储
2.在每一条记录的头部分别有flag/lock/cols对应这里的2c0102
3.这里的偏移量和dump出来的数据可以看出来两条记录是连续在一起(偏移量分别为:8168和8178)

更新一条记录

SQL> update t_xifenfei set name='XIFENFEI' where id=1;

1 row updated.

SQL> commit;

Commit complete.

SQL> alter system checkpoint;

System altered.

SQL> alter system dump datafile 4 block 175;

System altered.

SQL> select dump('XIFENFEI','16') from dual;

DUMP('XIFENFEI','16')
-------------------------------------
Typ=96 Len=8: 58,49,46,45,4e,46,45,49

我们可以但看到值有XFF改变为XIFENFEI,存储长度变大

dump数据块信息

bdba: 0x010000af
data_block_dump,data header at 0xb683c064
===============
tsiz: 0x1f98
hsiz: 0x16
pbl: 0xb683c064
     76543210
flag=--------
ntab=1
nrow=2
frre=-1
fsbo=0x16
fseo=0x1f75
avsp=0x1f69
tosp=0x1f69
0xe:pti[0]      nrow=2  offs=0
0x12:pri[0]     offs=0x1f75    ---->8053
0x14:pri[1]     offs=0x1f84    ---->8068
block_row_dump:
tab 0, row 0, @0x1f75
tl: 15 fb: --H-FL-- lb: 0x2  cc: 2
col  0: [ 2]  c1 02
col  1: [ 8]  58 49 46 45 4e 46 45 49
tab 0, row 1, @0x1f84
tl: 10 fb: --H-FL-- lb: 0x0  cc: 2
col  0: [ 2]  c1 03
col  1: [ 3]  43 48 46
end_of_block_dump
End dump data blocks tsn: 4 file#: 4 minblk 175 maxblk 175

通过对比第一次dump出来的数据块发现:row 0的值和偏移量发生了变化

bbed查看相关记录

BBED> set file 4 block 175
        FILE#           4
        BLOCK#          175

BBED> map
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175                                   Dba:0x010000af
------------------------------------------------------------
 KTB Data Block (Table/Cluster)

 struct kcbh, 20 bytes                      @0       

 struct ktbbh, 72 bytes                     @20      

 struct kdbh, 14 bytes                      @100     

 struct kdbt[1], 4 bytes                    @114     

 sb2 kdbr[2]                                @118     

 ub1 freespace[8031]                        @122     

 ub1 rowdata[35]                            @8153    

 ub4 tailchk                                @8188    

BBED> p kdbr
sb2 kdbr[0]                                 @118      8053   <--第一条row directory指针位置
sb2 kdbr[1]                                 @120      8068   <--第二条row directory指针位置

BBED> p *kdbr[1]
rowdata[15]
-----------
ub1 rowdata[15]                             @8168     0x2c

BBED> x /rnc
rowdata[15]                                 @8168    
-----------
flag@8168: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@8169: 0x00
cols@8170:    2

col    0[2] @8171: 2 
col    1[3] @8174: CHF


BBED> p *kdbr[0]
rowdata[0]
----------
ub1 rowdata[0]                              @8153     0x2c


BBED> x /r
rowdata[0]                                  @8153    
----------
flag@8153: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@8154: 0x02
cols@8155:    2

col    0[2] @8156:  0xc1  0x02 
col    1[8] @8159:  0x58  0x49  0x46  0x45  0x4e  0x46  0x45  0x49 

BBED> set count 64
        COUNT           64

 <32 bytes per line>

BBED> d /v
 File: /u01/oracle/oradata/ora11g/users01.dbf (4)
 Block: 175     Offsets: 8153 to 8191  Dba:0x010000af
-------------------------------------------------------
 2c020202 c1020858 4946454e 4645492c l ,......XIFENFEI,
 000202c1 03034348 462c0002 02c10203 l ......CHF,......
 58464602 068de8                     l XFF....

 <16 bytes per line>

从这里可以看到
1.这里可以看到三个值(XFF,CHF,XIFENFEI)均存在,但是通过p kdbr和dump block不能看到,因为row directory中无指针指定到该值上
2.也是通过row directory指针使得我们从原先看到的第一条记录处于数据块最底部变成了现在相对而言的数据部分最上层,
3.绝大多数情况:数据库更新一条记录,不是直接修改数据值,而是重新插入一条新记录,然后修改row directory指针指定到新的offset上
4.不是直接update,而是insert+指针来实现,这样做的好处:1)如果修改记录update值的长度发生变化(变大或者变小)那么该值之前的数据都要发生变动,对数据库来说成本太高.2)如果直接更新值可能导致其他数据变动,使得其他行受到影响.
5.由于是修改row directory指针,所以该处理方法的rowid值不会发生变化

使用oradebug修改数据库scn

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闲着无事看到几篇文章介绍了使用oradebug修改数据库scn的案例,这里也做了两个测试,发现该功能确实很巧妙,通过修改内存中的scn值,然后写入控制文件和数据文件,实现修改scn的方法,不过同样该方法的危害性极大,这里仅供测试使用,生产环境切不可乱使用,可能引起很严重后果
数据库版本信息

SQL> select * from v$version;

BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - Prod
PL/SQL Release 10.2.0.4.0 - Production
CORE    10.2.0.4.0      Production
TNS for Linux: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - Production

SQL> select '惜分飞' XIFENFEI FROM DUAL;

XIFENF
------
惜分飞

在open库中修改scn

SQL> oradebug setmypid
Statement processed.

--查看当前scn
SQL>  oradebug DUMPvar SGA kcsgscn_
kcslf kcsgscn_ [20009228, 20009248) = 00000000 0007A09F 00000019 00000000 00000000 00000000 00000000 20009034
SQL>  select CHECKPOINT_CHANGE# a from v$datafile;

         A
----------
    499314
    499314
    499314
    499314

SQL> select dbms_flashback.get_system_change_number a from dual;

         A
----------
    499877

SQL> select to_number('7A09F','xxxxxxxxx') from dual;

TO_NUMBER('7A09F','XXXXXXXXX')
------------------------------
                        499871

--修改内存中scn值(十进制)
SQL>  oradebug poke 0x20009228 4 8
BEFORE: [20009228, 2000922C) = 00000000
AFTER:  [20009228, 2000922C) = 00000008
SQL> oradebug DUMPvar SGA kcsgscn_
kcslf kcsgscn_ [20009228, 20009248) = 00000008 0007A0D8 00000052 00000000 00000000 00000000 00000000 20009034

SQL> col a for 999999999999999
SQL> select dbms_flashback.get_system_change_number a from dual;

         A
------------
34360238301

SQL> select to_number('8','xx')*4294967296+to_number('0007A0D8','xxxxxxxx') a from dual;

               A
----------------
     34360238296

--做一个checkpoint为了内存中的scn值写入控制文件和数据文件
SQL>  alter system checkpoint;

System altered.

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area  318767104 bytes
Fixed Size                  1267236 bytes
Variable Size              96471516 bytes
Database Buffers          213909504 bytes
Redo Buffers                7118848 bytes
Database mounted.
Database opened.

SQL> col a for 999999999999999
SQL> select CHECKPOINT_CHANGE# a from v$datafile;

               A
----------------
     34360238496
     34360238496
     34360238496
     34360238496

SQL> select CHECKPOINT_CHANGE# a from v$datafile_header;

               A
----------------
     34360238496
     34360238496
     34360238496
     34360238496

在mount库中修改scn

SQL> startup mount
ORACLE instance started.

Total System Global Area  318767104 bytes
Fixed Size                  1267236 bytes
Variable Size              96471516 bytes
Database Buffers          213909504 bytes
Redo Buffers                7118848 bytes
Database mounted.
SQL> oradebug setmypid
Statement processed.
--因为数据库是mount状态不能看到scn值
SQL>  oradebug DUMPvar SGA kcsgscn_
kcslf kcsgscn_ [20009228, 20009248) = 00000000 00000000 00000000 00000000 00000000 00000000 00000000 20009034
SQL>  col a for 999999999999999
SQL> select CHECKPOINT_CHANGE# a from v$datafile_header;

               A
----------------
     34360240739
     34360240739
     34360240739
     34360240739

--求出WRAP SCN值
SQL> select 34360240739/4294967296 from dual;

34360240739/4294967296
----------------------
            8.00011697

--修改内存中scn值(十六进制)
SQL> oradebug poke 0x20009228 4 0x0000000a
BEFORE: [20009228, 2000922C) = 00000000
AFTER:  [20009228, 2000922C) = 0000000A
SQL> oradebug DUMPvar SGA kcsgscn_
kcslf kcsgscn_ [20009228, 20009248) = 0000000A 00000000 00000000 00000000 00000000 00000000 00000000 20009034

SQL> alter database open;

Database altered.

SQL> select dbms_flashback.get_system_change_number a from dual
  2  ;

               A
----------------
     42949673074

--注意:使用此种方法修改BASE SCN如果不指定,会从0开始计数
SQL>  oradebug DUMPvar SGA kcsgscn_
kcslf kcsgscn_ [20009228, 20009248) = 0000000A 00000077 0000001C 00000000 00000000 00000000 00000000 20009034
SQL> select to_number('A','xx')*4294967296+to_number('00000077','xxxxxxxx') a from dual;

               A
----------------
     42949673079

SQL> alter system checkpoint;

System altered.

SQL> select CHECKPOINT_CHANGE# a from v$datafile_header;

               A
----------------
     42949673095
     42949673095
     42949673095
     42949673095

SQL> select CHECKPOINT_CHANGE# a from v$datafile;

               A
----------------
     42949673095
     42949673095
     42949673095
     42949673095

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area  318767104 bytes
Fixed Size                  1267236 bytes
Variable Size              96471516 bytes
Database Buffers          213909504 bytes
Redo Buffers                7118848 bytes
Database mounted.
Database opened.
SQL> select CHECKPOINT_CHANGE# a from v$datafile_header;

               A
----------------
     42949673231
     42949673231
     42949673231
     42949673231

在oradebug推进scn的过程中，需要注意不同平台，不同位数的ORACLE数据库可能推进方式有一定的区别，操作前最好在系统平台位数上进行测试，否则有可能导致恢复后果更加麻烦