关于Dump redo log 的示例，MOS 上的文档：[ID 1031381.6] 有详细说明。Dump 有两种方式：
（1）使用'alter session' 命令dumpredo header。
（2）使用'alter system dump logfile' 命令dump logfile contents。
可以在mount，nomout和open状态下使用如上命令，并且使用以上命令需要'alter system' 的权限。 可以使用该命令dump onlie redo log 或者归档文件。 当操作系统系统相同的情况下，还可以dump其他db的log 文件。
有如下dump 方法：
1.To dump records based in DBA (Data Block Address)
2.To dump records based on RBA (Redo Block Address)
3.To dump records based on SCN
4.To dump records based on time
5.To dump records based on layer and opcode
6.Dump the file header information
7.Dump an entire log file:
关于DBA的说明，参考：
根据DBA进行dump，主要是根据file和block 号来进行dump。 这个的block 是一个范围值。
ALTER SYSTEM DUMP LOGFILE 'filename' DBA MIN fileno . blockno DBA MAX fileno . blockno;
ALTER SYSTEM DUMP LOGFILE 'filename' DBA MIN fileno blockno DBA MAX fileno blockno;
否则会报： ORA-01963: Must specify a block number 错误。
如：
SYS@anqing1(rac1)> select * fromv$version where rownum=1;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise EditionRelease 10.2.0.4.0 - Prod
SQL>select distinct dbms_rowid.rowid_relative_fno(rowid) rel_fno,
dbms_rowid.rowid_block_number(rowid)blockno from ta;
REL_FNO BLOCKNO
---------- ----------
1 294608
1 294609
1 294612
1 294614
1 294621
1 294635
1 294643
1 294654
1 294656
1 294657
6 10385
REL_FNO BLOCKNO
---------- ----------
6 10393
6 10410
6 10411
6 10415
6 10416
6 10458
6 10461
6 10464
6 10465
6 10468
6 10472
SYS@anqing1(rac1)> selecta.group#,a.status,b.member from v$log a,v$logfile b where a.group#=b.group#;
GROUP# STATUS MEMBER
---------- --------------------------------------------------------------------
3 INACTIVE +DATA/anqing/onlinelog/redo03.log
2 INACTIVE +DATA/anqing/onlinelog/redo02.log
1 CURRENT +DATA/anqing/onlinelog/group_1.277.751552735
1 CURRENT +FRA/anqing/onlinelog/group_1.426.751552739
4 CURRENT +DATA/anqing/onlinelog/group_4.282.751560131
5 INACTIVE +DATA/anqing/onlinelog/group_5.283.751560139
6 rows selected.
SYS@anqing1(rac1)>
System altered.
SYS@anqing1(rac1)>
Statement processed.
SYS@anqing1(rac1)>
/u01/app/oracle/admin/anqing/udump/anqing1_ora_30373.trc
SYS@anqing1(rac1)>
[oracle@rac1 ~]$
/u01/app/oracle/admin/anqing/udump/anqing1_ora_30373.trc
Oracle Database 10g Enterprise EditionRelease 10.2.0.4.0 - Production
With the Partitioning, Real ApplicationClusters, OLAP, Data Mining
and Real Application Testing options
ORACLE_HOME =/u01/app/oracle/product/10.2.0/db_1
System name: Linux
Node name: rac1
Release: 2.6.18-194.el5
Version: #1 SMP Tue Mar 16 21:52:43 EDT 2010
Machine: i686
Instance name: anqing1
Redo thread mounted by this instance: 1
Oracle process number: 28
Unix process pid: 30373, image: oracle@rac1(TNS V1-V3)
*** 2011-08-08 22:10:37.053
*** ACTION NAME:() 2011-08-08 22:10:37.052
*** MODULE NAME:(sqlplus@rac1 (TNS V1-V3))2011-08-08 22:10:37.052
*** SERVICE NAME:(SYS$USERS) 2011-08-0822:10:37.052
*** SESSION ID:(127.27077) 2011-08-0822:10:37.052
DUMP OF REDO FROM FILE'+data/anqing/onlinelog/redo02.log'
Opcodes *.*
DBAs: (file # 6, block # 10458) thru (file #6, block # 10472)
RBAs: 0x000000.00000000.0000 thru0xffffffff.ffffffff.ffff
SCNs: scn: 0x0000.00000000 thru scn:0xffff.ffffffff
Times: creation thru eternity
FILEHEADER:
Compatibility Vsn = 169870336=0xa200400
Db ID=715014091=0x2a9e3fcb, Db Name='ANQING'
Activation ID=682502900=0x28ae2af4
Control Seq=4261=0x10a5, File size=102400=0x19000
File Number=2, Blksiz=512, File Type=2 LOG
descrip:"Thread0001, Seq# 0000000119, SCN 0x0000006ab1bc-0x0000006e0c84"
thread: 1 nab: 0x18ffd seq: 0x00000077 hws:0x2 eot: 0 dis: 0
resetlogs count: 0x2ccbc8df scn:0x0000.000704fa (460026)
resetlogs terminal rcv count: 0x0 scn:0x0000.00000000
prevresetlogs count: 0x2ebbfe8f scn: 0x0000.0006ce7b (446075)
prevresetlogs terminal rcv count: 0x0 scn: 0x0000.00000000
Low scn: 0x0000.006ab1bc (6992316) 07/30/2011 05:39:17
Nextscn: 0x0000.006e0c84 (7212164) 08/03/2011 14:14:34
Enabled scn: 0x0000.000704fa (460026)05/19/2011 12:38:55
Thread closed scn: 0x0000.006ab1bc (6992316)07/30/2011 05:39:17
Diskcksum: 0xd530 Calc cksum: 0xd530
Terminal recovery stop scn: 0x0000.00000000
Terminal recovery 01/01/1988 00:00:00
Mostrecent redo scn: 0x0000.00000000
Largest LWN: 1874 blocks
End-of-redo stream : No
Unprotected mode
Miscellaneous flags: 0x0
Thread internal enable indicator: thr: 0, seq:0 scn: 0x0000.00000000
REDO RECORD - Thread:1 RBA:0x000077.00000cd6.017c LEN: 0x0048 VLD: 0x01
SCN: 0x0000.006ac8a9 SUBSCN: 1 07/30/2011 08:28:08
CHANGE #1 MEDIA RECOVERY MARKERSCN:0x0000.00000000 SEQ: 0 OP:18.3
Reuse redo entry
Range reuse: tsn=1 base=8542185 nblks=8
REDO RECORD - Thread:1 RBA:0x000077.00006e99.0078 LEN: 0x0044 VLD: 0x01
SCN: 0x0000.006b7ae1 SUBSCN: 1 07/31/2011 06:18:10
CHANGE #1 MEDIA RECOVERY MARKERSCN:0x0000.00000000 SEQ: 0 OP:17.4
Datafile resize marker - file: 2 old size:153600 new size: 156160
REDO RECORD - Thread:1 RBA:0x000077.00007884.017c LEN: 0x0048 VLD: 0x01
SCN: 0x0000.006b8d16 SUBSCN: 1 07/31/2011 08:33:09
CHANGE #1 MEDIA RECOVERY MARKERSCN:0x0000.00000000 SEQ: 0 OP:18.3
Reuse redo entry
Range reuse: tsn=1 base=8542217 nblks=1024
*** 2011-08-08 22:10:54.783
END OF REDO DUMP
----- Redo read statistics for thread 1-----
Read rate (ASYNC): 51197Kb in 17.78s =>2.81 Mb/sec
Total physical reads: 51197Kb
Longest record: 8Kb, moves: 0/85186 (0%)
Change moves: 30223/143291 (21%), moved:5Mb
Longest LWN: 937Kb, moves: 6/66426 (0%),moved: 0Mb
Last redo scn: 0x0000.006e087b (7211131)
----------------------------------------------
[oracle@rac1 ~]$