Tablespace in backup mode

Printable View

03-01-2001, 07:34 AM
alexandre

Where oracle writes the changed blocks while the relative tablespace is in backup mode?
I had my production database on backup mode during 8 hours by mistake, and at the same time i got a lote of archive genereted. There are any relation between both?

Regards
Alexandre
03-01-2001, 07:39 AM
hrishy

yeah in hot backup mode the entire block information is written to the archived logs instead of writing the just the incremental change .hence what you just described is nothing surprising but a logical consequence.
03-01-2001, 07:41 AM
Dave_A

This site contains good information on the online backup issue:

http://www.backupcentral.com/oracle-hot-backup.html

HTH

David.
03-01-2001, 11:21 AM
tamilselvan

Hrishy, You are wrong. When the tablespace is in BACKUP mode, only the header is freezed, all transaction data is written into respective data block on the data files.
03-01-2001, 01:32 PM
jmodic

Quote:

Originally posted by tamilselvan
Hrishy, You are wrong. When the tablespace is in BACKUP mode, only the header is freezed, all transaction data is written into respective data block on the data files.

I think what Hrishy has said is totaly correct. He haven't said that db blocks are not written into db files. He only pointed out that during backup period whole db blocks are written into *redo logs*, hence the amount of redo logs filled during backup can be much higher than during normal operation.

I would just add that while tablespace is in backup mode, changed blocks are written to the red logs as whole blocks only at first change. In any subsequent change of the same block only the change vector is written to redo log.