Re: When database recovery is not an option

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.