Re: Data corruption

From: Jared Still <jkstill_at_gmail.com>
Date: Mon, 18 Apr 2005 13:20:01 -0700
Message-ID: <bf4638050418132022d02e0b@mail.gmail.com>

Here's a method to corrupt a block on linux. create tablespace corrupt datafile '/u01/oradata/dv03/corrupt.dbf' size 5m reuse
extent management local uniform size 8k
/

• create a table with 2 blocks create table corrupt_objects tablespace corrupt as select * from all_objects where rownum < 70 /
• get the block id select segment_type, relative_fno, file_id, extent_id, block_id, blocks from dba_extents where segment_name = 'CORRUPT_OBJECTS' / 14:12:51 rsysdevdb.radisys.com <http://rsysdevdb.radisys.com> - js001292_at_dv03 SQL> @id

SEGMENT_TYPE RELATIVE_FNO FILE_ID EXTENT_ID BLOCK_ID BLOCKS

------------------ ------------ ---------- ---------- ---------- -----------

TABLE 10 10 0 9 2 1 row selected.

#corrupt one block
dd conv=notrunc if=/dev/zero of=/u01/oradata/dv03/corrupt.dbf bs=8192 seek=10 count=1

• check for corrupt block eclare v_corrupt_count integer; begin sys.dbms_repair.check_object ( schema_name => 'JS001292', object_name => 'CORRUPT_OBJECTS', repair_table_name => 'REPAIR_TABLE', object_type => sys.dbms_repair.table_object, corrupt_count => v_corrupt_count );

dbms_output.put_line('Corrupt Count: ' || v_corrupt_count); end;
/
14:16:11 rsysdevdb.radisys.com <http://rsysdevdb.radisys.com> - js001292_at_dv03 SQL> @check
Corrupt Count: 1

PL/SQL procedure successfully completed.

• examine corruptions SQL> select schema_name,object_name, corrupt_type 14:18:38 2 from sys.repair_table 14:18:42 3 /

14:18:11 rsysdevdb.radisys.com <http://rsysdevdb.radisys.com> - js001292_at_dv03 SQL> select schema_name,object_name, corrupt_type 14:18:38 2 from sys.repair_table
14:18:42 3 /

SCHEMA_NAME OBJECT NAME CORRUPT_TYPE

------------------------------ ------------------------------ ------------

JS001292 CORRUPT_OBJECTS 6148
JS001292 CORRUPT_OBJECTS 6148 2 rows selected.

14:18:42 rsysdevdb.radisys.com <http://rsysdevdb.radisys.com> - js001292_at_dv03 SQL>

There are 2 rows as I ran this scenario twice.

HTH Jared

On 4/18/05, Peter Dixon <peterdixon001_at_hotmail.com> wrote:
>
> I am wanting to test dbs_repair , but I need to corrupt a block within my
> test database.
>
> Anybody know how to do it?
>
> --
> http://www.freelists.org/webpage/oracle-l
>

-- 
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist

--
http://www.freelists.org/webpage/oracle-l

Received on Mon Apr 18 2005 - 16:24:08 CDT