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RE: HELP URGENT CORRUPTED DATA

From: Freeman, Donald <dofreeman_at_state.pa.us>
Date: Fri, 19 May 2006 15:41:16 -0400
Message-ID: <51327ABA927BEF4B96590554CEA7832C060B957B@enhbgpri05.backup>


Paula, can you tell us exactly what error you are getting? How do you know that copy one and copy two are different? If we knew exactly how it was failing we might be able to provide more informed advice.

	-----Original Message-----
	From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Paula Stankus
	Sent: Friday, May 19, 2006 3:07 PM
	To: Alex Gorbachev
	Cc: oracle-l_at_freelists.org
	Subject: Re: HELP URGENT CORRUPTED DATA
	
	
	Alex,
	 
	Add to that that the system I have inherited had nologging and was not properly synchronizing their backups to nologging and wallah!  The problem is eye-balling the data we come up with no differences.  
	 
	My question is:  if there are hidden characters in data elements (so there are differences but we don't see them) - will a MINUS find them?
	 
	:)
	
	Alex Gorbachev <gorbyx_at_gmail.com> wrote:

		If you restore your database to a point in time in the past than
		transactional integrity is preserved. However, your application should
		be done in such a ways that business transaction is done as database
		transaction. This was the change is atomic. If your business
		transaction is done so that you have 10 commits for one business
		transaction than you might have got restored to the middle of this
		business transaction. Such inconsistencies shoule be than handled by
		application otherwise it's a design flaw. Often these might be
		bastches that are commiting work every so many records. For example,
		your purge batch might have purged half of your tables and introduced
		inconsistency.
		
		Also you didn't really say what exactly wrong with it and how you see
		the problem from application point of view - some query returns wrong
		result? Or it's just users see "something" wrong and you can't
		identify what's that. If the latter, than I would suggest to narrow
		down the area.
		
		Regarding point A - it's possible that index can be corrupted and you
		are correct in the way to detect it. Fix is to rebuild the index. Btw,
		PiT recovery should not cause index corruption becasue it's updated as
		part of the transaction and PiT recovery doesn't leave non-commited
		transactions on the half way.
		
		Point B - I am not sure about your question. Do you mean string comparison?
		
		Good luck!
		
		2006/5/19, Paula Stankus :

>
> Guys,
>
> We recovered a database, did a dbverify - everything looked good, exports
> are working fine. However, we recovered to an earlier point (few hours
> earlier) and on the "earlier" database we have no errors in a specific
> function of the application in the "later" one we have errors. We have been
> beating our hands against the brick wall doing comparisons of the data - the
> comparisons - table by table, column by column look okay. We have been
> working on this issue round-the-clock for days.
>
> Questions:
>
> A-Can an index be somehow causing this problem and can we use validate
> structure or something to be sure of the validity of the index? - analyze
> table validate structure...cascade...
>
> B-Can there be missing characters (characters we cannot visually see)
> causing the problem and can a "MINUS" find it if there is? :)
>
> Thanks,
>
> Paula
>
>
> ________________________________
> New Yahoo! Messenger with Voice. Call regular phones from your PC and save
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>
-- Best regards, Alex Gorbachev http://oracloid.blogspot.com

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Received on Fri May 19 2006 - 14:41:16 CDT

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