Re: Wierd quirk of HS/SR, probably not fixable

Simon Riggs wrote:
> On Tue, 2010-04-27 at 18:13 +0300, Heikki Linnakangas wrote:
>> Simon Riggs wrote:
>>> If pg_stop_backup() is run it creates the .backup file in the archive.
>>> In the absence of that file, we should be able to work out that
>>> pg_stop_backup() was not run.
>> It's just as likely that the file is there even though the backup didn't
>> finish, though.
>
> It's possible, but not likely. It would need to break at a very specific
> place for that to be the case. Whereas the test I explained would work
> for about 99% of the time between start and stop backup, except for the
> caveat I explained also.

I don't understand how you arrived at that figure. Roughly speaking,
there's two possibilities: backup_label is backed up before the bulk of
the data in base-directory or tablespaces, in which case it will almost
certainly be included in the backup, or it will be backed up after the
bulk of the data, in which case it will almost certainly not be included
if the backup is stopped prematurely. I don't know which is more common,
but both seem plausible.

> I'm not sure that pointing out a minor hole
> stops it being a worthwhile test? Surely if you care to fix the problem
> then a better test can only be a good thing?

Yeah, it might be worthwhile if it's not a lot of code.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com