Re: Backup history file should be replicated in Streaming Replication?

On Wed, Dec 23, 2009 at 7:50 PM, Heikki Linnakangas
<heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
> Ok. How about writing the history file in pg_stop_backup() for
> informational purposes only. Ie. never read it, but rely on the WAL
> records instead.

Sounds good. I'll make such change as a self-contained patch.

> I just realized that the current history file fails to recognize this
> scenario:
>
> 1. pg_start_backup()
> 2. cp -a $PGDATA data-backup
> 3. create data-backup/recovery.conf
> 4. postmaster -D data-backup
>
> That is, starting postmaster on a data directory, without ever calling
> pg_stop_backup(). Because pg_stop_backup() was not called, the history
> file is not there, and recovery won't complain about not reaching the
> safe starting point.
>
> That is of course a case of "don't do that!", but perhaps we should
> refuse to start up if the backup history file is not found? At least in
> the WAL-based approach, I think we should refuse to start up if we don't
> see the pg_stop_backup WAL record.

Agreed.

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center