Block Corruption

[Chucks_k]

Hi all,

We are getting to several occurences of ORA-01578: ORACLE data block corrupted (file # 9, block # 13)
ORA-01110: data file 9: '/oracle/dbs/tbs_91.f'

There are several block numbers which are mentioned. The alert log shows the what exactly is corrupt. It is a table. Now because of this our RMAN backups have failed too. So how do i recover the datafile?. Do i need to go back to the last successful backup restore the datafile and roll forward from there? if so, how do u tell RMAN which backup u need to restore from(just the datafile!)? Please help urgently!

Thanking u advance,
Chucks

[davey23uk]

yes you need to restore that datafile and roll forward

restore datafile 9; recover datafile 9; are the commands

[Chucks_k]

Davey,

Thanks for that, does this mean block corruption is ok (when recovery is complete)? or is it only ok if block corruption happens via media failure?

Thanks in advance

[davey23uk]

the restored file wont be corrupt and when rolled forward corruption shouldnt be introduced

[Thomasps]

Do i need to go back to the last successful backup restore the datafile and roll forward from there? if so, how do u tell RMAN which backup u need to restore from(just the datafile!)?
Chucks

You need not restore entire datafile rather use the feature BLOCKRECOVER to restore and recover in Oracle Block Level.

Eg.

BLOCKRECOVER DATAFILE 7 BLOCK 3 DATAFILE 2 BLOCK 235;

[Chucks_k]

Hi Thomas,

I thought of doing this. However i did not quite understand how it worked. Firstly, i had several corrupt blocks and secondly we had backups which were failing, hence the last good backup was about 7 days old. So i could have block recovered to the log sequence number of the of the last known good backup but then how would i have rolled forward to get it all in synch with the rest of the db?

BTW the datafile restore/recover worked fine. Thanks Davey for your help!

Thanks,
Chucks