Re: Block Corruption in empty pages in Oracle 11g

From: joel garry <joel-garry_at_home.com>
Date: Thu, 5 Aug 2010 10:19:40 -0700 (PDT)
Message-ID: <ad71eab2-98d7-49d7-892a-ce703a5c9eef_at_v6g2000prd.googlegroups.com>

On Aug 5, 4:54 am, Mladen Gogala <gogala.mla..._at_gmail.com> wrote:
> On Wed, 04 Aug 2010 20:08:15 -0700, zigzagdna wrote:
> > Another strange thing I noticed:
> > 1. When doing export backup, export backup reports about corrupted
> > blocks.
>
> Export is not a backup.

It is a logical backup. Says so right there in the docs. It has its uses, transactional recovery is not one of them. http://download.oracle.com/docs/cd/E11882_01/backup.112/e10642/glossary.htm#i997880

>
> > 2. When I do expdp no errors are reported. So question is why is exp
> > command checking empty blocks?
>
> Because it's doing full table scans. Full table scan stops at HWM, not
> before. Also, exp utility is deprecated in 11.2. Do not use it.
>

Which high water mark? Blocks up to the low high watermark are formatted, from there to the high high watermark they are not. This situation can occur if you use the compact option of shrink space, and can be fixed by doing a shrink without the compact option. http://download.oracle.com/docs/cd/E11882_01/server.112/e10595/schema003.htm#ADMIN12625

There are a couple of exceptions to the deprecation. I like the 10g typo in the exceptions: http://download.oracle.com/docs/cd/E11882_01/server.112/e10701/original_export.htm#SUTIL3634

Of course, I don't have 11g, so this is all academic to me. I could just be making embarrassing noises.

jg

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Received on Thu Aug 05 2010 - 12:19:40 CDT