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RE: 8i Standby Media Corrupt Blocks

From: Hitchman, Peter <Peter.Hitchman_at_thomson.com>
Date: Sat, 30 Oct 2004 14:58:41 +0100
Message-ID: <8D697B8FCEBB3744B3A1E4AE15E8331E4B882A@der-lon-msg-03.derwent.co.uk>


Hi Jack,
Are there any clob/blob(s) involved here? There is an 8.1.7.4 bug where by if the lob is marked as cache reads, nologging changes get generated, because in some cirumstances Oracle thinks it has read an inconsistent block in memory (Oracle have never released exact details.) The fix is to alter the lob setting just to "cache" or "no cache".

Regards

Pete

-----Original Message-----

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of JApplewhite_at_austin.isd.tenet.edu Sent: 28 October 2004 15:44
To: oracle-l_at_freelists.org
Subject: 8i Standby Media Corrupt Blocks

8.1.7.4 on HP-UX 11 64bit

I recently created a standby for one of our production databases. Got it in Managed Recovery mode, no problem. A couple of days later, the standby's Alert log started showing "Recovery is repairing media corrupt block X of file Y" errors for the 25 datafiles of our main application's (3rd Party COTS Student Info. package that doesn't work on 9i) tablespace.  No errors for the datafiles for System, RBS, Users, etc.

I checked and there are absolutely no tables or indexes in that tablespace with LOGGING = NO. In fact, the only tables in the entire database with LOGGING = NO are Global Temporary Tables.

I suspected the COTS app. of issuing "Alter Table...NoLogging" commands and slapped an After Alter database trigger on the primary. So far it has only caught the "Alter Tablespace Begin/End Backup" commands for our nightly hot backup - nothing else.

The Unrecoverable_Change# in v$Datafile continues to increment periodically in the primary for those 25 datafiles, leading me to believe that the NOLOGGING operations are continuing there. However, I'm at a loss to discover the source.

Am I an idiot? What am I missing?

I've created a TAR, but wanted to run this by the vast experience of this list for advice.

Thanks.

Jack C. Applewhite - Database Administrator Austin (Texas) Independent School District 512.414.9715 (wk)
512.935.5929 (pager)

   May have come a long way, but we got a long way to go.

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http://www.freelists.org/webpage/oracle-l Received on Sat Oct 30 2004 - 08:54:33 CDT

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