Re: Table updates during hot backups

In article <967210162.9931.0.nnrp-03.c2de6f3d_at_news.demon.co.uk>,   "Neil Cudd" <neil_at_cudd.demon.co.uk> wrote:
> Would I be right in saying that all changes made to a table in a
 specific
> tablespace, whilst that tablespace is in backup mode, are held in the
 online
> redo logs and applied only when the tablespace is bought back online
 (End
> Backup) ?
>
> If this is not the case, how are changes applied to the tablespace at
 the
> End Backup ?
>
> If you could refer me to any reference material on this subject (the
 Oracle
> Manuals are a little light on this subject), it would be appreciated.
>
> Thanks and regards,
>
> Neil Cudd.
>

Oracle applies changes to files in backup mode while the hot backup is in progress. That is why they refer to hot backups as fuzzy backups or images and the archive logs must be applied to the backup to bring the backup to a consistent point in time. Oracle stops updating the file header blocks while the file, tablespace, is in backup mode and when you issue the command to 'end backup' Oracle writes all dirty blocks for the affected files and updates the header block to bring the files to a consistent state relative to the scn number.

See the Backup and Recovery Manual for more detail.

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