Dul cannot load bootstrap to achieve unload table/user recovery, dulbootstrap

Dul cannot load bootstrap to achieve unload table/user recovery, dulbootstrap

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Title: dul cannot load bootstrap for unload table/user recovery

Author: XI Feifei

Recently, a friend accidentally caused a very big accident and almost went to court. during database migration, the system of the original database and other initial database files are deleted by remote misoperations. In addition, the disk space usage is very high and a small amount of data is written.

The final result is quite tragic. data files cannot be directly recovered at the file system level, and the database does not have any valid backup, table names, column names, and other information, in desperation, data files can only be recovered through underlying io block reorganization, but the tragedy once again, this disk also had a file such as system, finally, a relatively ideal data file is restored after multi-party restructuring.

However, the data files reorganized by third-party companies and the large amount of data recovered from undeleted business files have problems. We still need to further analyze and restore the data.

This article mainly describes how to use commands such as unload table/user to restore data as much as possible after dul cannot load the bootstrap command. you need to know the workload of hundreds of tables without table names/column names ......

Configure the system file in dul

D:\xifenfei\system01.dbfD:\TEMP\recover\dul\bak>dulData UnLoader: 11.2.0.0.4 - Internal Only - on Wed Sep 28 17:01:56 2016with 64-bit io functionsCopyright (c) 1994 2016 Bernard van Duijnen All rights reserved.Strictly Oracle Internal Use OnlyDUL> show datafiles;Sorry, no valid data files found in control.txt

Use the default data file configuration method in dul to make dul discover that the data file method is not feasible.

Arbitrary tablespace number and file number dul Identification

0 0 D:\xifenfei\system01.dbfD:\TEMP\recover\dul\bak>dulData UnLoader: 11.2.0.0.4 - Internal Only - on Wed Sep 28 17:00:27 2016with 64-bit io functionsCopyright (c) 1994 2016 Bernard van Duijnen All rights reserved.Strictly Oracle Internal Use OnlyDUL: Warning: File Type mismatch 1 != 8DUL: Warning: D:\xifenfei\system01.dbf Header tablespace number 3!= 0DUL: Warning: D:\xifenfei\system01.dbf Header relative file number 1 != 0Found db_id = 2948357999Found db_name = XIFENFEIDUL: Warning: Found mismatch while checking file D:\xifenfei\system01.dbfDUL: Warning: DUL osd_parameter or control.dul configuration errorDUL: Warning: Given file number(0) in control file does not match file# in dba(1)

Through this recognition, we can know that the tablespace number of system is 3 and the file number is 1.

Configure system again for dul Recognition

3 1 D:\xifenfei\system01.dbfD:\TEMP\recover\dul\bak>dulData UnLoader: 11.2.0.0.4 - Internal Only - on Wed Sep 28 17:03:46 2016with 64-bit io functionsCopyright (c) 1994 2016 Bernard van Duijnen All rights reserved.Strictly Oracle Internal Use OnlyDUL: Warning: File Type mismatch 1 != 8Found db_id = 2948357999Found db_name = XIFENFEIDUL> show datafiles;ts# rf# start blocks offs open err file name3 1 0 320257 0 1 0 D:\xifenfei\system01.dbf

Dul normally identifies the system file, but we know from experience that tablespace 3 is definitely faulty, so there are still many problems in subsequent operations.

An error occurred while trying to recover dul bootstrap.

DUL> bootstrap;Scanning SYSTEM tablespace to locate compatibility segment ...DUL: Warning: No files found for tablespace 0Reading EXT.dat 0 entries loaded and sorted 0 entriesReading SEG.dat 0 entries loadedReading COMPATSEG.dat 0 entries loadedReading SCANNEDLOBPAGE.dat 0 entries loaded and sorted 0 entriesDUL: Error: No compatibility segments found

Due to the tablespace number error, dul cannot load to the bootstrap $ table. In addition, bootstrap $ is lost in the system file recovered based on bbed analysis.

Try to manually load the data dictionary required by dul

DUL> unload table OBJ $2 storage (tablespace 3 segobjno 18 file 1 block 240 );. unloading table OBJ $79074 rows unloadedDUL> unload table TAB $ (OBJ # number, DATAOBJ # number, 2 cluster C_OBJ # (OBJ #) 3 storage (tablespace 3 segobjno 2 tabno 1 file 1 block 144 );. unloading table TAB $4482 rows unloadedDUL> unload table COL $ (OBJ # number, COL # number, SEGCOL # number, 2 cluster C_OBJ # (OBJ #) 3 storage (tablespace 3 segobjno 2 tabno 5 file 1 block 144 );. unloading table COL $114491 rows unloadedDUL> unload table USER $2 cluster C_USER # (USER #) 3 storage (tablespace 3 segobjno 10 tabno 1 file 1 block 208 );. unloading table USER $96 rows unloaded ---- Other tables are omitted and processed in sequence as neededTry to use dul to restore DataDUL> desc portal_emr.BASEELEMENT; Table PORTAL_EMR.BASEELEMENTobj # = 87200, dataobj # = 87200, ts # = 9, file # = 7, block # = 458tab # = 0, segcols = 8, clucols = 0 Column information: icol #01 segcol #01 BENAME len 30 type 1 VARCHAR2 cs 852 (ZHS16GBK) icol #02 segcol #02 TYPENAME len 30 type 1 VARCHAR2 cs 852 (ZHS16GBK) icol #03 segcol #03 TYPETYPE len 22 type 2 NUMBER (4000) icol #04 segcol #04 BEXMLTEXT len 852 type 1 VARCHAR2 cs (ZHS16GBK) icol #05 segcol #05 DEPTGROUPCODE len 30 type 1 VARCHAR2 cs 852 (ZHS16GBK) icol #06 segcol #06 ISCOMMON len 22 type 2 NUMBER) icol #07 segcol #07 BESPELL len 15 type 1 VARCHAR2 cs 852 (ZHS16GBK) icol #08 segcol #08 ELEMTYPE len 22 type 2 NUMBER (0) DUL> show datafiles; ts # rf # start blocks offs open err file name3 1 0 320257 0 1 0 D: \ xifenfei \ system01.dbf9 7 0 4170425 0 1 0 D: \ BaiduYunDownload \ PORTAL_EMRDUL> unload table portal_emr.BASEELEMENT ;. unloading table BASEELEMENT 1913 rows unloaded

After dul cannot load the bootstrap command, it is described that the normal unload table/user function can be implemented by manually loading the data dictionary. The general processing logic is discarded, and only the scan method can be used and the unload method has no table name, the column name processing method maximizes recovery.

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