Re: Hot backup questions

Just one clarification on Connor's comment: an entire block is only written the first time the block is changed. After that change vectors are logged as usual.

HTH. Pete

Connor McDonald wrote:

> Brian Peasland wrote:
> >
> > Jeremiah Wilton wrote:
> > >
> > > Tablespaces in backup mode are not out of sync, so they have no need to
> > > resync when they are taken out of backup mode. Blocks are written to
> > > the datafiles during backup mode as they are during normal operation.
> >
> > Is this true? Blocks are written to the datafiles during backup mode? If
> > so, then the datafile is changed while it is being backed up resulting
> > in an invalid backup of the datafile. If memory serves me right, while a
> > tablespace is in backup mode, any changes to it are written to the redo
> > logs. And the changes are written a block at a time. This means that the
> > redo logs might fill up faster if there is high volume. After the
> > tablespace is taken out of backup mode, the changes are then applied to
> > the datafiles.
> >
> > HTH,
> > Brian
>
> Nope - the datafiles are written to as the backup takes place...The
> reason the redo's fill up faster is that entire blocks are written
> instead of 'rows' whilst that tablespace is in backup mode...
>
> HTH
> --
> ===========================================
> Connor McDonald
> "These views mine, no-one elses etc etc"
> connor_mcdonald_at_yahoo.com
>
> "Some days you're the pigeon, and some days you're the statue."

Received on Tue Oct 26 1999 - 10:30:30 CDT