案例:Oracle dul数据挖掘 磁盘损坏dul提取数据文件中表的数据及l

Posted 2020-07-28 烟台天萃荷净

通过使用Oracle DUL工具提取损坏磁盘里的数据库文件中的表及lob字段中内容

在有次8i的库恢复中,因为硬盘损坏导致几个表出现很多诡异性坏块,尝试使用dul对其进行挖掘数据,当时使用dul 9 遇到一个难题:当一张表中有lob类型,同时又有varchar2类型,而且varchar2类型数据中包含回车键,使得解决起来很麻烦(因为export_mode=false支持lob,但是不支持字符串含回车;export_mode=true支持字符串含回车,但是不支持lob),最后放弃了对部分数据的挖掘.这个问题让我一直不甘心,今天测试dul 10 发现是用export_mode=true可以完美解决该问题

1.创建模拟表和插入数据

SQL> desc t_xff
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 C_BLOB                                             BLOB
 C_VARCHAR                                          VARCHAR2(4000)

SQL> declare
  2  a_blob BLOB;
  3  bfile_name BFILE := BFILENAME(‘ULTLOBDIR‘,‘awr_ora11g_2012-06-01_174_175.html‘);
  4  begin
  5  insert into t_xff(C_BLOB,C_VARCHAR) values (
  6  empty_blob())
 12  returning C_BLOB into a_blob;
 13  dbms_lob.fileopen(bfile_name);
 14  dbms_lob.loadfromfile(a_blob, bfile_name, dbms_lob.getlength(bfile_name));
 15  dbms_lob.fileclose(bfile_name);
 16  commit;
 17  end;
 18  /

PL/SQL procedure successfully completed.

SQL> select length(c_varchar),dbms_lob.getlength(c_blob) from t_xff;

LENGTH(C_VARCHAR) DBMS_LOB.GETLENGTH(C_BLOB)
----------------- --------------------------
               61                    4282573

SQL>  select c_varchar from t_xff;

C_VARCHAR
---------------------------------------------------------------

数据库异常恢复

2.dul 挖数据

[[email protected] dul]$ ./dul

Data UnLoader: 10.2.0.5.13 - Internal Only - on Mon Jul  2 04:29:10 2012
with 64-bit io functions

Copyright (c) 1994 2012 Bernard van Duijnen All rights reserved.

 Strictly Oracle Internal Use Only

DUL> bootstrap;
DUL> desc chf.t_xff;
Table CHF.T_XFF
obj#= 51353, dataobj#= 51353, ts#= 4, file#= 4, block#=67
      tab#= 0, segcols= 2, clucols= 0
Column information:
icol# 01 segcol# 01       C_BLOB len 4000 type 113 BLOB
  LOB Segment: dataobj#= 51354, ts#= 4, file#= 4, block#=75 chunk=1
  LOB Index: dataobj#= 51355, ts#= 4, file#= 4, block#=83
icol# 02 segcol# 02    C_VARCHAR len 4000 type  1 VARCHAR2 cs 852(ZHS16GBK)

--export_mode=false
DUL> unload table chf.t_xff;
. unloading (index organized) table     LOB01000053      65 rows unloaded
Preparing lob metadata from lob index
Reading LOB01000053.dat 65 entries loaded and sorted 65 entries
. unloading table                     T_XFF       1 row  unloaded

--导出数据文件
-rw-r--r-- 1 oracle oinstall 6.1K Jul  2 04:15 LOB01000053.dat
-rw-r--r-- 1 oracle oinstall  335 Jul  2 04:15 LOB01000053.ctl
-rw-r--r-- 1 oracle oinstall 8.2M Jul  2 04:15 CHF_T_XFF.dat
-rw-r--r-- 1 oracle oinstall  263 Jul  2 04:15 CHF_T_XFF.ctl

----export_mode=true
DUL> unload table chf.t_xff;
. unloading (index organized) table     LOB01000053
DUL: Warning: Recreating file "LOB01000053.ctl"
      65 rows unloaded
Preparing lob metadata from lob index
Reading LOB01000053.dat 65 entries loaded and sorted 65 entries
. unloading table                     T_XFF       1 row  unloaded

--导出数据文件
-rw-r--r-- 1 oracle oinstall    6229 Jul  2 04:29 LOB01000053.dat
-rw-r--r-- 1 oracle oinstall     335 Jul  2 04:29 LOB01000053.ctl
-rw-r--r-- 1 oracle oinstall 4285027 Jul  2 04:29 CHF_T_XFF.dmp

3.导入数据测试

sqlldr导入

SQL> truncate table chf.t_xff;

Table truncated.

[[email protected] dul]$ sqlldr chf/xifenfei control=CHF_T_XFF.ctl

SQL*Loader: Release 10.2.0.1.0 - Production on Mon Jul 2 04:23:18 2012

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

SQL*Loader-510: Physical record in data file (CHF_T_XFF.dat) is longer than the maximum(1048576)
SQL*Loader-2026: the load was aborted because SQL Loader cannot continue.
[[email protected] dul]$ sqlldr chf/xifenfei control=CHF_T_XFF.ctl readsize=20971520

SQL*Loader: Release 10.2.0.1.0 - Production on Mon Jul 2 04:26:50 2012

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

SQL> select length(c_varchar),dbms_lob.getlength(c_blob) from chf.t_xff;

no rows selected

--试验结果证明在出现表中同时有lob和varchar2列(含回车)时,export_mode=false不能正常工作

imp导入

SQL> drop table chf.t_xff;

Table dropped.

[[email protected] dul]$ imp chf/xifenfei file=CHF_T_XFF.dmp full=y

Import: Release 10.2.0.1.0 - Production on Mon Jul 2 04:30:30 2012

Copyright (c) 1982, 2005, Oracle.  All rights reserved.


Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options

Export file created by EXPORT:V07.00.07 via conventional path

Warning: the objects were exported by Bernard‘s DUL, not by you

. importing Bernard‘s DUL‘s objects into CHF
. importing Bernard‘s DUL‘s objects into CHF
. . importing table                        "T_XFF"          1 rows imported

SQL> select length(c_varchar),dbms_lob.getlength(c_blob) from t_xff;

LENGTH(C_VARCHAR) DBMS_LOB.GETLENGTH(C_BLOB)
----------------- --------------------------
               61                    4282573

SQL>  select c_varchar from t_xff;

C_VARCHAR
---------------------------------------------------------------

数据库异常恢复

--试验结果证明在出现表中同时有lob和varchar2列(含回车)时,export_mode=true正常工作

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Oracle dul数据挖掘

磁盘损坏dul提取数据文件中表中的数据及lob字段