Re: "Resurrected" data files - problem?

On 08/11/2007, Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at> wrote:
>
> We use a tape backup software that does "incremental backups"
> as follows:
>
> - In a full backup, all files are backed up.
> - In an incremental backup, only the files with modification
> date after the last backup are backed up.
>
> Now when such a backup is restored, you first have to restore
> the full backup, and then the incremental backup.
>
> The problem is that files which were deleted between the full
> and the incremental backup will get "resurrected" after such a
> restore.
>
> So if we perform our database backups with incremental
> backups as described above, we could end up with additional
> files after the restore, because PostgreSQL files can get
> deleted (e.g. during DROP TABLE or TRUNCATE TABLE).
>
> My question is:
>
> Could such "resurrected" files (data files, files in
> pg_xlog, pg_clog or elsewhere) cause a problem for the database
> (other than the obvious one that there may be unnecessary files
> about that consume disk space)?
>
>
This will not work at all.

Try re-reading the instructions on backup in the manual.

oh and always, always, always test your backup works before you actually
need it!

Peter Childs