Re: BUG #3110: Online Backup introduces Duplicate OIDs

On Thu, 2008-06-05 at 11:39 -0400, Tom Lane wrote:
> Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> > * In the release note comments, add that in a future release we will add
> > a parameter to recovery.conf "require_backup_label" which defaults to
> > "true".
>
> The problem that I'm having with that idea is that it breaks
> crash-recovery after replay starts, because we intentionally remove the
> backup label once we've read it. (And no, please do not suggest
> rewriting the config file ...)

LOL :-)

Hmm, seems we can check for the backup_label.old if the first check
fails. We don't actually remove the backup_label, we just move it out of
the way.

> Basically it seems that we need a more robust way to distinguish
> "beginning a recovery" from "resuming a recovery". Perhaps more state
> in pg_control is needed?

That would work also.

Which do you prefer? The former is back patchable eventually, the latter
is not, even if I like it as a cleaner solution.

Or should we just go with shouting DON'T REMOVE THE backup_label FILE in
the docs?

For that matter, it would be easier to list the files you *are* allowed
to remove *ever* somewhere prominent and leave it at that, rather than
try to explain all the various ways the other files are essential.

--
Simon Riggs www.2ndQuadrant.com
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