Re: Hot Backup Consistency Question.

"Steve Roper" <s_r_roper_at_yahoo.com> wrote in message news:5dbecdba.0407160346.3bb04fa4_at_posting.google.com...
> Hello,
>
> I've read a fair amount about Hot Backups, but never had to perform
> them in practice.
>
> The question I have concerns hot backup of multiple tablespaces.
>
> By all accounts the way to do this is to perform serial backups i.e.
>
> Alter tablespace1 begin backup
> backup tablespace1
> alter tablespace1 end backup
>
> Alter tablespace2 begin backup
> backup tablespace2
> alter tablespace2 end backup
>
> Assuming that lots of DML is happening in both tablespaces, there may
> well be referential ties between the two.
>
> So the scenario is...
> 1) Tablespace1 backup started.
> 2) A trigger in tablespace2 updates a table in tablespace1
> 3) Tablespace1 backup finished.
> 4) Tablespace2 backup started and completed.
>
>
> I understand that thanks to the redo activity, that the live database
> will have consistent data.
>
> However, is it the case that the backup files created will have
> inconsistent data because the update actioned by the trigger will not
> have been recorded in the tablespace1 backup?
>
> And if you have to restore these, will this still be the case, or is
> there some process that I haven't seen yet that deals with this?
>
> regards
>
> Steve Roper

That is why you also back up the archive logs. Also do a log switch at the end of the backup and backup all the archive logs. They will be used in recovery.
Jim Received on Fri Jul 16 2004 - 07:00:17 CDT