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RE: Help - Corrupted Block - Lob Segment - NOLOGGING

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Date: Mon, 23 Oct 2006 16:43:23 -0400
Message-ID: <>

I meant to include the release.

We are on Oracle We just upgraded from Oracle I think the problem originated as we were shutting down the Oracle version of the database in preparation for the migration (and getting users off the system).

Oracle Support said nothing about dropping RIDs in the block, just about updating them with empty_blob(). If I drop RIDs, I am concerned the block may still be corrupt, but will have 100% free space and thus be available for other insertion attempts, which I expect will fail with the same error. At least that is how I think it will work.

Thanks for the link to Tanel's presentation. I will have a look.


-----Original Message-----
From: Wolfson Larry - lwolfs [] Sent: Monday, October 23, 2006 2:49 PM
To: Sam Bootsma;
Subject: RE: Help - Corrupted Block - Lob Segment - NOLOGGING


        What release is this?

Here's a terrific presentation about LOBS from Tanel Poder. take a look at this.

Did OS say you could drop RIDs in that block, and if so, how will that effect your app?


-----Original Message-----
[] On Behalf Of Sam Bootsma Sent: Monday, October 23, 2006 1:47 PM
Subject: Help - Corrupted Block - Lob Segment - NOLOGGING

Our third-party version control software uses an Oracle database as its repository.

Documents are stored in a BLOB column in an Oracle table. It is NOT stored "in_row" and logging is turned off (for performance reasons they told me).

We recently encountered a bad block, and I have since determined there are additional bad blocks, but it is just one block that is continually giving us a problem.

When a user attempts to check an object into the repository, they often get the error message:

E03020003: Database Error: [CAI/PT][ODBC Oracle 8 driver][Oracle]ORA-01578: ORACLE data block corrupted (file # 31, block # 123533)
ORA-01110: data file 31: '/san1/oradata/PROD/harvestblob01.dbf' ORA-26040: Data block was loaded using the NOLOGGING option

This tells me the block still has free space to insert new data; i.e., the block is on the free list.

Here is some information about the tablespace housing this lob segment (from dba_tablespaces):
Allocation type='system'

Can somebody tell me what I need to do to allow users to continue to check items into this repository without receiving the error message and with minimal data loss; i.e., limiting data loss to the content of corrupted block# 123533. I think I can do this if I am able to permanently get this block off the free list, but how can I do that?

I have contacted Oracle Support, but they have been of limited assistance. They had me review metalink note 293515.1 "ORA-1578 ORA-26040 in a LOB segment - Script to solve the errors". But this has not helped our situation. The metalink note directs us to create a table with a single column of type rowid. Then run an Oracle procedure to populate this table with rowids for rows in the corrupted block. After this we set concat to "#", then update the lob column to "empty_blob". I did this and commited, but users receive the same error message.

Thanks for any and all suggestions.

Sam Bootsma
Oracle Database Administrator
Information Technology Services
George Brown College
Phone: 416-415-5000 x4933
Fax: 416-415-4836


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Received on Mon Oct 23 2006 - 15:43:23 CDT

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