Re: Hot backups vs. Offline Backups

Peter Moore <pt_at_chaff.demon.co.uk> wrote:
>Those people who think that you can't back up an open and active Oracle
>database are *WRONG*.
 

>If you are running Oracle7 you can backup a database while it is in use.
 

>There are only two provisos:
 

> 1) You are running in ARCHIVELOG mode.
> 2) You issue the ALTER TABLESPACE name BEGIN/END BACKUP commands
> before/after backing up the appropriate data files.
 

>As long as you ensure that you also take backups of your control files and
>archivelog files at the same time you will have no problems.

What happens to your database integrity in the following scenario:

1. you're in the middle of a hot backup of tablespace 'a'
2. during that backup, a transaction occurs that effects objects in tablspaces 'a' *and* 'b'?
3. you finsish the hot back up of 'a' and being a hot backup of tablespace 'b'.

If you have to restore both tablespaces, will you still have database integrity?

I could be wrong and please correct me if I am, but wouldn't the backup of tablespace 'a' be missing parts of the transaction that the backup of tablespace 'b' contains? And if so, then don't you have to do an ALTER TABLESPACE x BEGIN/END BACKUP on all tablespaces that might be updated during the backup?

--
Chuck Hamilton
chuckh_at_ix.netcom.com

Never share a foxhole with anyone braver than yourself!