月归档：三月 2013

undo异常事务回滚规则分析

发表于 2013 年 3 月 10 日 由 惜分飞

undo事务具体是如何回滚,这里提供了大概的异常undo事务回滚的一个过程(更加准确的说，这个过程是在以下几种情况中发生的过程：1.数据库非正常关闭后启动,2.事务未提交会话终止)，数据库先扫描所有回滚段，然后发现有事务未提交回滚段,然后根据这个回滚段定位到undo block,然后定位到data block，当一个undo block回滚完成之后，利用undo的链表规则完成下一个undo block的回滚操作，依次类此，从而实现数据库的回滚操作；回滚的过程是先回滚后操作的块(先进后出原则)
创建测试表

SQL> create table chf.t_xifenfei(a varchar2(4000));

Table created.

SQL> insert into chf.t_xifenfei values (lpad('www.xifenfei.com',4000,'a'));

1 row created.

SQL> insert into chf.t_xifenfei values (lpad('www.xifenfei.com',4000,'b'));

1 row created.

SQL> commit;

Commit complete.

SQL> update chf.t_xifenfei set a=lpad('www.xifenfei.com',4000,'F');

2 rows updated.

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

   REL_FNO   BLOCK_NO
---------- ----------
         9        421
         9        422

确保表中有两条记录,存储在两个block中

查询测试表相关信息

SQL> select object_id,data_object_id from dba_objects where owner='CHF' AND OBJECT_NAME='T_XIFENFEI';

 OBJECT_ID DATA_OBJECT_ID
---------- --------------
     53917          53917

SQL> SELECT TO_CHAR(53917,'XXXXX') FROM DUAL;

TO_CHA
------
  D29D

SQL> SELECT XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBASQN,UBAREC FROM v$transaction;

    XIDUSN    XIDSLOT     XIDSQN     UBAFIL     UBABLK     UBASQN     UBAREC
---------- ---------- ---------- ---------- ---------- ---------- ----------
         2         28        513          2       3627        253          1

SQL> select to_char(28,'xxx') from dual;

TO_C
----
  1c

SQL> select to_char(513,'xxx') from dual;

TO_C
----
 201

------------------------
--xid=0002.01c.00000201
------------------------

SQL> variable dba varchar2(30)
SQL> exec :dba := dbms_utility.make_data_block_address(2,3627);

PL/SQL procedure successfully completed.

SQL> print dba

DBA
--------------------------------
8392235

SQL> select to_char(253,'xxx') from dual;

TO_C
----
  fd
---------------------
--uda=800e2a.00fd.01
---------------------

通过这些查询可以得知:
1)chf.t_xifenfei的object_id/data_object_id的值为53917/D29D
2)xid=0002.01c.00000201(Xid=usn.slot.wrap)
3)uda=800e2a.00fd.01(Uba=undo block dba.undo record number.undo block sequence number)

dump rollback header

SQL> select * from v$rollname where usn=2;

       USN NAME
---------- ------------------------------
         2 _SYSSMU2$

SQL>  alter system dump undo header "_SYSSMU2$";

System altered.

 index  state cflags  wrap#    uel         scn            dba            parent-xid    nub     stmt_num    cmt
  ------------------------------------------------------------------------------------------------
0x00    9    0x00  0x0201  0x0012  0x0b2c.c02c9b85  0x00800e27  0x0000.000.00000000  0x00000001   0x00000000  1358780575
   ………………
0x1b    9    0x00  0x0201  0x0028  0x0b2c.c02c9bf4  0x00800e27  0x0000.000.00000000  0x00000001   0x00000000  1358780575
0x1c   10    0x80  0x0201  0x0002  0x0b2c.c02ca2a8  0x00800e2b  0x0000.000.00000000  0x00000002   0x00000000  0
0x1d    9    0x00  0x0200  0x0004  0x0b2c.c02c9a8b  0x00800e26  0x0000.000.00000000  0x00000001   0x00000000  1358780444
   ………………
0x2f    9    0x00  0x0201  0x001a  0x0b2c.c02ca1da  0x00800e29  0x0000.000.00000000  0x00000001   0x00000000  1358784176

------------------------------------------------------------------------------
==> Transaction Table 
==>  state      0 = IDLE 
                1 = Collecting       2 = Prepared            3 = Committed 
                4 = Forced Abort     5 = Forced Commit       6 = Forced Mixed 
                7 = try again later 
                9 = No TX (Committed)    10= 'a' = Active local TX 
==>  cflags     1 = TX has started storing collecting information 
 
                2 = TX has forced the collecting information 
                4 = Prepared TX needs distributed recovery 
                10= Rollback failed on this TX - mark SMON for recover 
                20= TX has rolled back its updates 
==>  wrap#      is incremented TX slot reuse. 
==>  uel        ? 
==>  scn        SCN for the TX prepare / commit 
==>  dba        is DBA of HEAD of the REDO - Ie: The MOST RECENT CHANG 
------------------------------------------------------------------------------

--通过上面的提示可以知道index为0x1c为未提交事务

SQL> select to_number('800e2b','xxxxxxx') from dual;

TO_NUMBER('800E2B','XXXXXXX')
-----------------------------
                      8392235

SQL> select dbms_utility.data_block_address_block(8392235) "block",
  2  dbms_utility.data_block_address_file(8392235)  "file" from dual;

     block       file
---------- ----------
      3627          2
--v$transaction表中查询出来的UBAFIL与UBABLK一致

dump undo block

SQL> alter system dump datafile 2 block 3627;

System altered.

UNDO BLK:  
xid: 0x0002.01c.00000201  seq: 0xfd  cnt: 0x1   irb: 0x1   icl: 0x0   flg: 0x0000
 
 Rec Offset      Rec Offset      Rec Offset      Rec Offset      Rec Offset
---------------------------------------------------------------------------
0x01 0x0fdc     
 
*-----------------------------
* Rec #0x1  slt: 0x1c  objn: 53917(0x0000d29d)  objd: 53917  tblspc: 9(0x00000009)
*       Layer:  11 (Row)   opc: 1   rci 0x00  <--- 表明指向下一个block 
Undo type:  Regular undo   Last buffer split:  No 
Temp Object:  No 
Tablespace Undo:  No 
rdba: 0x00800e2a   <--- 为下一个undo block rdba
*-----------------------------
KDO undo record:
KTB Redo 
op: 0x03  ver: 0x01  
op: Z
Array Update of 1 rows: 
tabn: 0 slot: 0(0x0) flag: 0x2c lock: 0 ckix: 71
ncol: 1 nnew: 1 size: 0
KDO Op code:  21 row dependencies Disabled
  xtype: XAxtype KDO_KDOM2 flags: 0x00000080  bdba: 0x024001a6  hdba: 0x024001a3
itli: 2  ispac: 0  maxfr: 4858

--bdba表示undo对应的data block,这里对应的是datafile 9 block 422
--hdba表示chf.t_xifenfei的extent 0的 first block(first mapbit)

SQL> select to_number('800e2a','xxxxxxx') from dual;

TO_NUMBER('800E2A','XXXXXXX')
-----------------------------
                      8392234

SQL> select dbms_utility.data_block_address_block(8392234) "block",
  2  dbms_utility.data_block_address_file(8392234)  "file" from dual;

     block       file
---------- ----------
      3626          2

SQL> alter system dump datafile 2 block 3626;

System altered.

UNDO BLK:  
xid: 0x0002.01c.00000201  seq: 0xfd  cnt: 0x1   irb: 0x1   icl: 0x0   flg: 0x0000
 
 Rec Offset      Rec Offset      Rec Offset      Rec Offset      Rec Offset
---------------------------------------------------------------------------
0x01 0x0fac     
 
*-----------------------------
* Rec #0x1  slt: 0x1c  objn: 53917(0x0000d29d)  objd: 53917  tblspc: 9(0x00000009)
*       Layer:  11 (Row)   opc: 1   rci 0x00   <--- 表明指向下一个block 
Undo type:  Regular undo    Begin trans    Last buffer split:  No 
Temp Object:  No 
Tablespace Undo:  No 
rdba: 0x00000000  <--- 下一个block为 0x00000000,表示事务到此为止
*-----------------------------
uba: 0x00800e29.00fd.24 ctl max scn: 0x0b2c.c02c99cc prv tx scn: 0x0b2c.c02c9a27
txn start scn: scn: 0x0b2c.c02ca0b3 logon user: 0
 prev brb: 8392230 prev bcl: 0
KDO undo record:
KTB Redo 
op: 0x03  ver: 0x01  
op: Z
Array Update of 1 rows: 
tabn: 0 slot: 0(0x0) flag: 0x2c lock: 0 ckix: 71
ncol: 1 nnew: 1 size: 0
KDO Op code:  21 row dependencies Disabled
  xtype: XAxtype KDO_KDOM2 flags: 0x00000080  bdba: 0x024001a5  hdba: 0x024001a3
itli: 2  ispac: 0  maxfr: 4858

--bdba表示undo对应的data block,这里对应的是datafile 9 block 421

XID: this is the transaction ID, which matches the value made up previously from the query on V$TRANSACTION.

CNT: this is the number of undo records in this block.

IRB: this is the index if the first record to be considered in case of a rollback.

OBJN: this is the object number being altered by the undo record. This matches the value previously queried from DBA_OBJECTS.

RCI: this is the next undo record in the chain to be examined. When rolling back transactions, these undo records are applied one by one on the data blocks to undo the changes.

1. undo链表的意思为:从IRB表示undo 回滚的开始，RCI表示未IRB对应的下一条记录，依次类推。当RCI为0,而且rdba不为0的时候，表示undo 记录关联到下一个block；当RCI为0，而且rdba也为0表示undo结束
2. undo事务回滚是倒序的,这里可以看到事务先读取block 422，再读取block 421

dump data block

SQL> alter system dump datafile 9 block 421;

System altered.

Block header dump:  0x024001a5
 Object id on Block? Y
 seg/obj: 0xd29d  csc: 0xb2c.c02ca2bc  itc: 2  flg: E  typ: 1 - DATA
     brn: 0  bdba: 0x24001a1 ver: 0x01 opc: 0
     inc: 0  exflg: 0
 
 Itl           Xid                  Uba         Flag  Lck        Scn/Fsc
0x01   0x0009.01d.00000232  0x0083dbe0.02be.22  C---    0  scn 0x0b2c.c02ca2a8
0x02   0x0002.01c.00000201  0x00800e2a.00fd.01  ----    1  fsc 0x0000.00000000

SQL> alter system dump datafile 9 block 422;

System altered.

Block header dump:  0x024001a6
 Object id on Block? Y
 seg/obj: 0xd29d  csc: 0xb2c.c02ca2bd  itc: 2  flg: E  typ: 1 - DATA
     brn: 0  bdba: 0x24001a1 ver: 0x01 opc: 0
     inc: 0  exflg: 0
 
 Itl           Xid                  Uba         Flag  Lck        Scn/Fsc
0x01   0x0009.01d.00000232  0x0083dbe0.02be.23  C---    0  scn 0x0b2c.c02ca2a8
0x02   0x0002.01c.00000201  0x00800e2b.00fd.01  ----    1  fsc 0x0000.00000000

这里可以看到Xid,Uba和上面计算出来的一致，看出来事务未提交标记和上述一致.

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关于blockrecover 解决坏块相关测试与总结

发表于 2013 年 3 月 1 日 由 惜分飞

悲剧的客户因为IBM p系列小机更换电源导致主机直接掉电,起来后发现数据库出现不少坏块,而且还有部分坏块中含有回滚事务,导致alert日志一直报smon回滚遇到坏块错误，该数据库版本是9.2.0.8 RAC,根据客户的备份情况,为了减少对业务的影响,决定使用blockrecover对其处理.这里通过10g数据库大概模拟出现含事务坏块的情况以及处理过程,重现了我们在处理的时候不确定的一些知识.
创建测试表

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> conn /as sysdba
Connected.
SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/XFF/archivelog
Oldest online log sequence     231
Next log sequence to archive   233
Current log sequence           233
SQL> conn chf/xifenfei
Connected.
SQL> create table t_xifenfei
  2  as
  3  select * 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
------------------ ---------- ----------
AAANIqAAEAAAAAcAAA          4         28
AAANIqAAEAAAAAcAAB          4         28
AAANIqAAEAAAAAcAAC          4         28
AAANIqAAEAAAAAcAAD          4         28
AAANIqAAEAAAAAcAAE          4         28
AAANIqAAEAAAAAcAAF          4         28
AAANIqAAEAAAAAcAAG          4         28
AAANIqAAEAAAAAcAAH          4         28
AAANIqAAEAAAAAcAAI          4         28

9 rows selected.

当前的seq是233(也就是说我在233归档上创建了t_xienfei表)

dbv检查block

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

DBVERIFY: Release 10.2.0.4.0 - Production on Sun Jan 20 22:16:16 2013

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

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


DBVERIFY - Verification complete

Total Pages Examined         : 1280
Total Pages Processed (Data) : 904
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 38
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 44
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 294
Total Pages Marked Corrupt   : 0
Total Pages Influx           : 0
Highest block SCN            : 3224018224 (2860.3224018224)

证明无任何坏块

切换归档

SQL> alter system switch logfile;

System altered.

SQL> /

System altered.

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/XFF/archivelog
Oldest online log sequence     233
Next log sequence to archive   235
Current log sequence           235

现在已经切换seq到235

rman备份我们需要测试block(file 4 block 28)对应的数据文件

RMAN>  backup datafile 4 format '/u01/oracle/oradata/xff_4.rman';

具体见:rman制造坏块,bbed修复坏块

模拟数据库进行其他操作

SQL> alter system switch logfile;

System altered.

SQL> /

System altered.

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/XFF/archivelog
Oldest online log sequence     235
Next log sequence to archive   237
Current log sequence           237
SQL> conn chf/xifenfei
Connected.
SQL> create table t_xff 
  2  as
  3  select * from dba_objects;

Table created.

SQL> alter system switch logfile;

System altered.

主要是为了模拟对其他block操作,对于block 28的恢复影响

对block 28进行操作

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/XFF/archivelog
Oldest online log sequence     237
Next log sequence to archive   239
Current log sequence           239
SQL> update chf.t_xifenfei set object_name='www.xifenfei.com';

9 rows updated.

SQL> commit;

Commit complete.

SQL> alter system switch logfile;

System altered.

SQL> /

System altered.

SQL> /

System altered.

在seq为239的时候对block 28进行了一次update操作

模拟其他业务操作

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/XFF/archivelog
Oldest online log sequence     240
Next log sequence to archive   242
Current log sequence           242
SQL> delete from chf.t_xff ;

50491 rows deleted.

SQL> commit;

Commit complete.

SQL> alter system switch logfile;

System altered.

SQL> /

System altered.

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/XFF/archivelog
Oldest online log sequence     242
Next log sequence to archive   244
Current log sequence           244
SQL>  alter system switch logfile;  

System altered.

SQL> /

System altered.

这里可以知道在seq为246的时候做了备份归档操作

备份归档操作

RMAN> backup archivelog all format '/u01/oracle/oradata/xff_arch_%U' delete input;

模拟继续操作

SQL> alter system switch logfile;

System altered.

SQL> /

System altered.

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/XFF/archivelog
Oldest online log sequence     248
Next log sequence to archive   250
Current log sequence           250

SQL> update chf.t_xifenfei set object_name='www.orasos.com' where rownum<5;

4 rows updated.

这里可以发现,在seq为250的时候我们再次对block 28进行了操作

使用rman制造坏块

RMAN> BLOCKRECOVER DATAFILE 4 block 28 clear;

dbv检查坏块

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

DBVERIFY: Release 10.2.0.4.0 - Production on Sun Jan 20 23:01:24 2013

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

DBVERIFY - Verification starting : FILE = /u01/oracle/oradata/XFF/users01.dbf
Page 28 is influx - most likely media corrupt
Corrupt block relative dba: 0x0100001c (file 4, block 28)
Fractured block found during dbv: 
Data in bad block:
 type: 6 format: 2 rdba: 0x0100001c
 last change scn: 0x0b2c.c02ab081 seq: 0x1 flg: 0x04
 spare1: 0x0 spare2: 0x0 spare3: 0x0
 consistency value in tail: 0xb0c4a6ea
 check value in block header: 0x393f
 computed block checksum: 0xc917



DBVERIFY - Verification complete

Total Pages Examined         : 1280
Total Pages Processed (Data) : 903
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 38
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 47
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 291
Total Pages Marked Corrupt   : 1
Total Pages Influx           : 1
Highest block SCN            : 3224022228 (2860.3224022228)

强制kill数据库

[oracle@xifenfei ~]$ ps -ef|grep pmon
oracle    9744  9638  0 23:03 pts/1    00:00:00 grep pmon
oracle   32156     1  0 14:17 ?        00:00:10 ora_pmon_XFF
[oracle@xifenfei ~]$ kill -9 32156
[oracle@xifenfei ~]$ ps -ef|grep pmon
oracle    9751  9638  0 23:03 pts/1    00:00:00 grep pmon

为了模拟含事务的block出现坏块

启动数据库

SQL> startup mount
ORACLE instance started.

Total System Global Area  306184192 bytes
Fixed Size                  1267164 bytes
Variable Size             109054500 bytes
Database Buffers          188743680 bytes
Redo Buffers                7118848 bytes
Database mounted.
SQL> ALTER DATABASE OPEN;

Database altered.

数据库启动正常

查询坏块

SQL> select count(*) from chf.t_xifenfei;
select count(*) from chf.t_xifenfei
                         *
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 4, block # 28)
ORA-01110: data file 4: '/u01/oracle/oradata/XFF/users01.dbf'

alert日志

Sun Jan 20 23:04:37 2013
SMON: enabling tx recovery
Sun Jan 20 23:04:37 2013
Database Characterset is ZHS16GBK
Sun Jan 20 23:04:37 2013
Hex dump of (file 4, block 28) in trace file /u01/oracle/admin/XFF/bdump/xff_smon_9775.trc
Corrupt block relative dba: 0x0100001c (file 4, block 28)
Fractured block found during buffer read
Data in bad block:
 type: 6 format: 2 rdba: 0x0100001c
 last change scn: 0x0b2c.c02ab081 seq: 0x1 flg: 0x04
 spare1: 0x0 spare2: 0x0 spare3: 0x0
 consistency value in tail: 0xb0c4a6ea
 check value in block header: 0x393f
 computed block checksum: 0xc917
Reread of rdba: 0x0100001c (file 4, block 28) found same corrupted data
ORACLE Instance XFF (pid = 8) - Error 1578 encountered while recovering transaction (9, 37) on object 53802.
Sun Jan 20 23:04:38 2013
Errors in file /u01/oracle/admin/XFF/bdump/xff_smon_9775.trc:
ORA-01578: ORACLE data block corrupted (file # 4, block # 28)
ORA-01110: data file 4: '/u01/oracle/oradata/XFF/users01.dbf'

通过试验步骤和alert日志可以发现因为block有事务,但是被标记为了坏块,所以smon无法回滚该事务,从而出现alert中类似提示

继续切换归档

SQL> alter system switch logfile;

System altered.

SQL> /

System altered.

SQL> /

System altered.

SQL> /

System altered.

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/XFF/archivelog
Oldest online log sequence     252
Next log sequence to archive   254
Current log sequence           254

移走归档

[oracle@xifenfei archivelog]$ ls -l
total 2224
-rw-r----- 1 oracle oinstall  360960 Jan 20 22:59 1_247_792679299.dbf
-rw-r----- 1 oracle oinstall    1024 Jan 20 22:59 1_248_792679299.dbf
-rw-r----- 1 oracle oinstall 1630208 Jan 20 23:04 1_249_792679299.dbf
-rw-r----- 1 oracle oinstall  249344 Jan 20 23:09 1_250_792679299.dbf
-rw-r----- 1 oracle oinstall    1024 Jan 20 23:09 1_251_792679299.dbf
-rw-r----- 1 oracle oinstall    4608 Jan 20 23:09 1_252_792679299.dbf
-rw-r----- 1 oracle oinstall    1024 Jan 20 23:09 1_253_792679299.dbf
[oracle@xifenfei archivelog]$ mkdir bak
[oracle@xifenfei archivelog]$ mv *.dbf bak
[oracle@xifenfei archivelog]$ ll
total 4
drwxr-xr-x 2 oracle oinstall 4096 Jan 20 23:11 bak

为了重现,当我们使用blockrecover恢复的时候,如果缺少归档会怎么样

尝试blockrecover

RMAN> BLOCKRECOVER DATAFILE 4 block 28;

Starting blockrecover at 20-JAN-13
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=135 devtype=DISK
allocated channel: ORA_DISK_2
channel ORA_DISK_2: sid=126 devtype=DISK
allocated channel: ORA_DISK_3
channel ORA_DISK_3: sid=125 devtype=DISK
allocated channel: ORA_DISK_4
channel ORA_DISK_4: sid=124 devtype=DISK

channel ORA_DISK_1: restoring block(s)
channel ORA_DISK_1: specifying block(s) to restore from backup set
restoring blocks of datafile 00004
channel ORA_DISK_1: reading from backup piece /u01/oracle/oradata/xff_4.rman
channel ORA_DISK_1: restored block(s) from backup piece 1
piece handle=/u01/oracle/oradata/xff_4.rman tag=TAG20130120T222333
channel ORA_DISK_1: block restore complete, elapsed time: 00:00:01

starting media recovery

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of blockrecover command at 01/20/2013 23:11:41
RMAN-06053: unable to perform media recovery because of missing log
RMAN-06025: no backup of log thread 1 seq 253 lowscn 12286830510311 found to restore
RMAN-06025: no backup of log thread 1 seq 252 lowscn 12286830510307 found to restore
RMAN-06025: no backup of log thread 1 seq 251 lowscn 12286830510305 found to restore
RMAN-06025: no backup of log thread 1 seq 250 lowscn 12286830509979 found to restore
RMAN-06025: no backup of log thread 1 seq 249 lowscn 12286830489543 found to restore
RMAN-06025: no backup of log thread 1 seq 248 lowscn 12286830489541 found to restore
RMAN-06025: no backup of log thread 1 seq 247 lowscn 12286830489279 found to restore

alert日志记录

Sun Jan 20 23:11:38 2013
alter database recover datafile list clear
Sun Jan 20 23:11:38 2013
Completed: alter database recover datafile list clear
Sun Jan 20 23:11:38 2013
Starting block media recovery
Sun Jan 20 23:11:39 2013
Media Recovery Log /u01/oracle/oradata/XFF/archivelog/1_235_792679299.dbf
Sun Jan 20 23:11:41 2013
alter database recover cancel
Sun Jan 20 23:11:41 2013
Media Recovery Canceled
Completed: alter database recover cancel

blockrecover恢复途中或者异常终止,dbv检测

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

DBVERIFY: Release 10.2.0.4.0 - Production on Sun Jan 20 23:18:29 2013

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

DBVERIFY - Verification starting : FILE = /u01/oracle/oradata/XFF/users01.dbf
Page 28 is marked corrupt
Corrupt block relative dba: 0x0100001c (file 4, block 28)
Bad check value found during dbv: 
Data in bad block:
 type: 6 format: 2 rdba: 0x0100001c
 last change scn: 0x0b2c.c02b0248 seq: 0x1 flg: 0x04
 spare1: 0x0 spare2: 0x0 spare3: 0x0
 consistency value in tail: 0x02480601
 check value in block header: 0x13fc
 computed block checksum: 0x663b



DBVERIFY - Verification complete

Total Pages Examined         : 1280
Total Pages Processed (Data) : 903
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 38
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 47
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 291
Total Pages Marked Corrupt   : 1
Total Pages Influx           : 0
Highest block SCN            : 3224022228 (2860.3224022228)

在blockrecover处理过程，或者处理失败的后,block依然是坏块，如果遇到这类情况,没有事务可以直接指定seq/scn/time的方法来恢复,如果有事务,需要指定恢复时间点过该事务的时间点,让smon能够正常回滚,从而使得smon进程正常工作

还原归档后继续测试

[oracle@xifenfei archivelog]$ mv bak/* ./

RMAN> BLOCKRECOVER DATAFILE 4 block 28;

starting media recovery
archive log thread 1 sequence 247 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_247_792679299.dbf
…………
media recovery complete, elapsed time: 00:00:01
Finished blockrecover at 20-JAN-13

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

DBVERIFY: Release 10.2.0.4.0 - Production on Sun Jan 20 23:15:43 2013

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

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


DBVERIFY - Verification complete

Total Pages Examined         : 1280
Total Pages Processed (Data) : 904
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 38
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 47
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 291
Total Pages Marked Corrupt   : 0
Total Pages Influx           : 0
Highest block SCN            : 3224023169 (2860.3224023169)

>
blockrecover处理alert日志

Sun Jan 20 23:15:01 2013
Media Recovery Log /u01/oracle/oradata/XFF/archivelog/1_250_792679299.dbf
Sun Jan 20 23:15:01 2013
Media Recovery Log /u01/oracle/oradata/XFF/archivelog/1_251_792679299.dbf
Sun Jan 20 23:15:01 2013
Recovery of Online Redo Log: Thread 1 Group 3 Seq 252 Reading mem 0
  Mem# 0: /u01/oracle/oradata/XFF/redo03.log
Sun Jan 20 23:15:01 2013
Recovery of Online Redo Log: Thread 1 Group 1 Seq 253 Reading mem 0
  Mem# 0: /u01/oracle/oradata/XFF/redo01.log
Sun Jan 20 23:15:01 2013
Recovery of Online Redo Log: Thread 1 Group 2 Seq 254 Reading mem 0
  Mem# 0: /u01/oracle/oradata/XFF/redo02.log
Sun Jan 20 23:15:02 2013
Completed block media recovery

补充说明
1.在9i中使用blockrecover会在Archive destination中生产block的备份文件,类似469_519791_3063_2442393528.bkd(file 469 block 519791),需要注意Archive destination目录结尾需要”/”,不然可能出现直接写入和该目录并列的Archive destination+blockrecover产生文件;10g中不生成该文件;如果该block在9i中未备份,也不会在生产相关文件,而是利用归档恢复.
2.blockrecover需要还原从该block从备份之后的所有归档(如果被备份起来需要还原出来),如果缺少归档可能导致恢复失败,包括基于scn/seq/time的等
3.blockrecover在执行过程中或者执行异常终止,该block依然是坏块,不会对其他block产生影响.在使用blockrecover出现异常终止后的block修复,在后续blog中提供解决方法
4.对于不含事务的坏块,如果数据允许丢失可以通过设置event跳过坏块(特殊block除外),然后重建对象;对于含event的block 坏块,建议使用blockrecover处理或者直接恢复数据文件,如果没有备份,考试使用event跳过事务回滚,然后屏蔽坏块处理

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