DBV-00201: Block, DBA 224, marked corrupt for invalid redo application

Question

Hello Oracle gurus,
I ran a "dbv file=<datafile name>" against one of my datafiles that I suspected corruption in. it reported back with
DBV-00201: Block, DBA 224, marked corrupt for invalid redo application
DBV-00201: Block, DBA 243, marked corrupt for invalid redo application
DBV-00201: Block, DBA 244, marked corrupt for invalid redo application
DBV-00201: Block, DBA 245, marked corrupt for invalid redo application
DBV-00201: Block, DBA 246, marked corrupt for invalid redo application
Total Pages Marked Corrupt : 5
I then ran a "backup validate check logical database" in RMAN and it populated v$database_block_corruption with 2 rows, the same blocks as listed from the dbv output. I found the offending table, dropped it, and purged it from the recyclebin and ran another "backup validate check logical database". The v$database_block_corruption table returned no rows after this. However, when I run another "dbv file=<datafile name>", it is still reporting the same thing as before: DBV-00201: Block, DBA 224, marked corrupt for invalid redo application
Have I fixed the corruption problem? If yes, why is the dbv command still reporting corruption? If not, do I need to use dbms_repair?
Respectfully,
Mimi

Answer 1

DROP TABLE does not write on blocks/extents used by the dropped table (even with PURGE option). This explain why dropping the table does not remove the DBV error messages.
1* select tablespace_name, extent_management, allocation_type
from dba_tablespaces where tablespace_name='P1'
SQL> /
TABLESPACE_NAME                EXTENT_MAN ALLOCATIO
P1                             LOCAL      SYSTEM
SQL> select * from v$version;
BANNER
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
PL/SQL Release 11.2.0.1.0 - Production
CORE    11.2.0.1.0      Production
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production
SQL> create table t(x int) tablespace p1;
Table created.
SQL> alter tablespace p1 read only;
Tablespace altered.
SQL> drop table t purge;
Table dropped.
SQL> select * from t;
select * from t
ERROR at line 1:
ORA-00942: table or view does not exist
SQL> alter tablespace p1 read write;
Tablespace altered.But note also:
$ oerr dbv 201
201,    1, "Block, DBA %d, marked corrupt for invalid redo application"
// *Cause:  The block was marked corrupt by the Oracle database server
//          for invalid redo application, ex: media recovery of a NOLOGGING
//          object or direct loaded data.
// *Action: If the block is not currently allocated to a database object,
//          then no action is required. If the block is allocated, then
//          the object will need to be rebuilt, or data to be reloaded.If you are using NOLOGGING operations or direct loaded data and because you have dropped the related object,
you don't need to care about these errors.
Edited by: P. Forstmann on 20 juin 2010 20:17