Typically 1578s are due to hardware hickups or a known bug. Dbverify
will not capture all types of data corruption. The only truly safe way
to capture physical corruption of a datablock is to get it into the
buffer cache with a statement that exercises the datablock.
The easiest way to determine the extent of the corruption is to dump the
logical representation of the datablock(s) to a trace file. If this dump
is successful it will give you the content of the block in a very raw
format. It will also give you information regarding the type of block it
is. Here is that syntax while logged in as sysdba:
Alter system dump datafile 7 block 191659;
If this is really important data you may want to open a TAR with Oracle
Support as they have a tool that will interpret the data out of this
block for you. I would also suggest that you look for other possible
corruptions around this block by dumping them and selecting the data
appropriately. Proactively, you may want to select from all the data you
can that exists on that device.
If the data is corrupted beyond recognition then you can try to mine the
data out of related objects (e.g. if it is a table's datablock, then you
can look at the related index or visa versa). You just have to be
creative with your select statements (force the use of an index or not).
To learn more about what is affected you can run the following query:
SELECT tablespace_name, segment_type, owner, segment_name
FROM dba_extents
WHERE file_id = 7
and 191659 between block_id AND block_id + blocks - 1;
For more detail see the Oracle Metalink note number 28814.1.
Regards,
Michael Sale
Co-author: Oracle 9i on Windows 2000 Tips & Techniques
-----Original Message-----
Faroult
Sent: Tuesday, May 28, 2002 2:05 PM
To: Multiple recipients of list ORACLE-L
Kevin Lange wrote:
>
> Hey gang;
> I have an 8.0.5.0 database running on a Solaris platform.
>
> The developer is running a simple query which returns the error
>
> ERROR at line 1:
> ORA-01578: ORACLE data block corrupted (file # 7, block # 191659)
> ORA-01110: data file 7: '/u08/oradata/TTCT/dynamici01.dbf'
>
> So I run dbverify (dbv) against the file and it says all is OK.
>
> $ dbv file=dynamici01.dbf
> DBVERIFY: Release 8.0.5.0.0 - Production on Tue May 28 13:2:7 2002
> (c) Copyright 1998 Oracle Corporation. All rights reserved.
> DBVERIFY - Verification starting : FILE = dynamici01.dbf
> DBVERIFY - Verification complete
> Total Pages Examined : 409600
> Total Pages Processed (Data) : 0
> Total Pages Failing (Data) : 0
> Total Pages Processed (Index): 158376
> Total Pages Failing (Index): 0
> Total Pages Empty : 0
> Total Pages Marked Corrupt : 0
> Total Pages Influx : 0
>
> Does anyone have any suggestions about this other than rebuilding the
> database (it is a clone of our production ... it will just set the
> developer back if we have to clone it) ?
>
> Thanks
>
> Kevin
Kevin,
Try to check what kind of segment this block belongs to (DBA_EXTENTS
+ DBA_SEGMENTS - extents are identified by the block# of their first
block plus the number of contiguous blocks, so you have tolook for the
extent for which 191659 is >= first block and < first block + extent
size. It will tell you whether it's a table (and which one), index, temp
or rollback segment, and you will be better armed to take a decision.
There may be less time-costly than cloning the production database
again.
--
Regards,
Stephane Faroult
Oriole Software
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: Stephane Faroult
INET: [EMAIL PROTECTED]
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: Michael P Sale
INET: [EMAIL PROTECTED]
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