Re: How does one manually corrupt a database (database file, redo logs and backups)

From: Radoulov, Dimitre <cichomitiko_at_gmail.com>
Date: Sun, 3 Sep 2006 09:24:01 +0200
Message-ID: <004e01c6cf29$eed6a150$6700a8c0@ETNOTEAM6XUQ9V>

>>>>echo "<somewhat string>" >> oracle_file
>>>>
>>>>This should alter the file offset (I don't know if this is
>>>>the correct technical term) for every binary file and thus
>>>>making it corrupted towards and Oracle db.
>>>>The command should also work for both unix and windows.
>
> try it, I doubt it..appending junk at the end of a datafile might
> not cause any headache until the next autoextend...

On Solaris:

09:18:51 SYS_at_ora10gr2> create tablespace test datafile '/app/oracle/oradata/ora10gr2/tes01.dbf' size 5m reuse;

Tablespace created.

09:18:59 SYS_at_ora10gr2> !dbv file=/app/oracle/oradata/ora10gr2/tes01.dbf

DBVERIFY: Release 10.2.0.2.0 - Production on Sun Sep 3 09:19:12 2006

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

DBVERIFY - Verification starting : FILE = /app/oracle/oradata/ora10gr2/tes01.dbf

DBVERIFY - Verification complete

Total Pages Examined         : 640
Total Pages Processed (Data) : 0
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 0
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 8
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 632
Total Pages Marked Corrupt   : 0
Total Pages Influx           : 0
Highest block SCN            : 8128994 (0.8128994)

09:19:12 SYS_at_ora10gr2> !echo "hello hello hello" >> /app/oracle/oradata/ora10gr2/tes01.dbf

09:19:18 SYS_at_ora10gr2> !dbv file=/app/oracle/oradata/ora10gr2/tes01.dbf

DBVERIFY: Release 10.2.0.2.0 - Production on Sun Sep 3 09:19:23 2006

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

DBVERIFY - Verification starting : FILE = /app/oracle/oradata/ora10gr2/tes01.dbf

DBVERIFY - Verification complete

Total Pages Examined         : 640
Total Pages Processed (Data) : 0
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 0
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 8
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 632
Total Pages Marked Corrupt   : 0
Total Pages Influx           : 0
Highest block SCN            : 8128994 (0.8128994)

09:19:23 SYS_at_ora10gr2> !dd if=/dev/null of=/app/oracle/oradata/ora10gr2/tes01.dbf count=1 seek=3 bs=8192 0+0 records in
0+0 records out

09:19:35 SYS_at_ora10gr2> !dbv file=/app/oracle/oradata/ora10gr2/tes01.dbf

DBVERIFY: Release 10.2.0.2.0 - Production on Sun Sep 3 09:19:41 2006

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

DBV-00102: File I/O error on FILE (/app/oracle/oradata/ora10gr2/tes01.dbf) during end read operation (-1)

09:19:41 SYS_at_ora10gr2> alter system checkpoint;

System altered.

09:19:57 SYS_at_ora10gr2> !dd if=/dev/null of=/app/oracle/oradata/ora10gr2/tes01.dbf count=1 seek=1 bs=8192 0+0 records in
0+0 records out

09:20:11 SYS_at_ora10gr2> alter system checkpoint;

System altered.

09:20:18 SYS_at_ora10gr2>

alert.log content:

Sun Sep 3 09:18:55 2006
create tablespace test datafile '/app/oracle/oradata/ora10gr2/tes01.dbf' size 5m reuse
Sun Sep 3 09:18:57 2006
Starting control autobackup
Control autobackup written to DISK device

        handle
'/siriofs/oracle/backup/ora10gr2_bck/control_c-3888264759-20060903-0a' Completed: create tablespace test datafile '/app/oracle/oradata/ora10gr2/tes01.dbf' size 5m reuse Sun Sep 3 09:19:57 2006
Beginning global checkpoint up to RBA [0xbe.14d9e.10], SCN: 8129034 Completed checkpoint up to RBA [0xbe.14d9e.10], SCN: 8129034 Sun Sep 3 09:20:17 2006
Beginning global checkpoint up to RBA [0xbe.14e15.10], SCN: 8129079 Sun Sep 3 09:20:18 2006
Errors in file /app/oracle/admin/ora10gr2/bdump/ora10gr2_ckpt_4436.trc:

ORA-01171: datafile 8 going offline due to error advancing checkpoint
ORA-01110: data file 8: '/app/oracle/oradata/ora10gr2/tes01.dbf'
ORA-01115: IO error reading block from file 8 (block # 1)
ORA-27063: number of bytes read/written is incorrect

Additional information: 8192
Completed checkpoint up to RBA [0xbe.14e15.10], SCN: 8129079

Regards
Dimitre

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Received on Sun Sep 03 2006 - 02:24:01 CDT