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Re: When database recovery is not an option

From: <mpir_at_compuserve.com>
Date: Tue, 20 Jul 1999 19:32:08 GMT
Message-ID: <7n2iro$5uh$1@nnrp1.deja.com>


Minor variation on the previous message:

When the corrupted block is detected, Oracle gives a message that identifies it (file, block, etc.) Using this, a routine to copy/access the affected table (only one table per block, remember, so only one object is at risk that you are aware of or at a time, but there may be others) using the rowids, which can be derived to skip the affected block.

In article <3791BC55.F9694E4D_at_sap-ag.de>,   Ralph Ganszky <ralph.ganszky_at_sap-ag.de> wrote:
> Hi Robert,
>
> if the DBA have enough space to restore a part of his database he can
> recover this part without problems. But he need space for the system
> tablespace, the tablespace with the rollback segments, may be the
> tablespace
> for temporary segments and the tablespace with the corrupted
datablocks.
> When he set all other tablespaces offline after he startup this
second
> database in mount status, then he can recover this tablespace to every
> point in time for that he have archived redo logs. Than he can export
> the data and import it into his production system.
>
> If he only needs a part of his table he can read around the corrupted
> blocks.
> He should reed an article in oracles technet DocID 108491.543 (Data
Block
> Corruption)
> who he can read around the corrupted blocks. The article is on
Oracle7 but
>
> I think he can translate it to Oracle8 if needed.
>
> If he is brave enough he can also set an event 10231 to skip corrupted
> blocks
> in the session which should read the table.
>
> Robert Chung wrote:
>
> > A DBA that I know has Oracle database with corrupt data blocks.
> > Database is in archive log mode and he does have backup, but cannot
> > recover database because his machine is under-powered (Last time
when
> > they experienced database failure and restored database, it took
THREE
> > DAYS just to restore data files from their cheap slow tape device
and
> > apply archive logs. The database was down for three days!)
> >
> > So he is trying to somehow extract data from his corrupt data files.
> > Oracle database reports corrupt data blocks and refuses to extract
any
> > more data from his tables. "export" utility is not working either.
> > Is there any way to get some of clean data back? Possibly reading
> > data file binary dump? He does not need to recover 100% of
database.
> > The company is willing to accept 90% of recovery or more. Thank you
> > in advance.
>
> --
> Best Regards,
>
> Ralph Ganszky
>
> * The above opinions are mine and do not represent any official
> * standpoints of my employer or third-party organizations.
>
>

--
Joseph R.P. Maloney, CCP,CSP,CDP
MPiR, Inc.
502-451-7404
some witty phrase goes here, I think.

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Share what you know. Learn what you don't. Received on Tue Jul 20 1999 - 14:32:08 CDT

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