Re: Remove Deprecated Exclusive Backup Mode

On Wed, Feb 27, 2019 at 2:27 AM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> On Tue, Feb 26, 2019 at 12:20 PM Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
> > So, let me clarify the situations;
> >
> > (1) If backup_label and recovery.signal exist, the recovery starts safely.
> > This is the normal case of recovery from the base backup.
> >
> > (2)If backup_label.pending and recovery.signal exist, as described above,
> > PANIC error happens at the start of recovery. This case can happen
> > if the operator forgets to rename backup_label.pending, i.e.,
> > operation mistake. So, after PANIC, the operator needs to fix her or
> > his mistake (i.e., rename backup_label.pending) and restart
> > the recovery.
> >
> > (3) If backup_label.pending exists but recovery.signal doesn't, the server
> > ignores (or removes) backup_label.pending and do the recovery
> > starting the pg_control's REDO location. This case can happen if
> > the server crashes while an exclusive backup is in progress.
> > So crash-in-the-middle-of-backup doesn't prevent the recovery from
> > starting in this idea.
>
> The if-conditions for 1 and 2 appear to be the same, which is confusing.

Using other name like backup_in_progress instead of backup_label.pending
may help a bit for your concern? That is,

(1) backup_label and recovery.signal
(2) backup_in_progress and recovery.signal

Regards,

--
Fujii Masao