Re: Allowing multiple concurrent base backups

Magnus Hagander <magnus(at)hagander(dot)net> writes:
> On Tue, Jan 11, 2011 at 19:51, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Seems like either one of these is fairly problematic in that you have to
>> have some monstrous kluge to get the backup_label file to appear with
>> the right name in the tarfile. How badly do we actually need this?
>> I don't think the use-case for concurrent base backups is all that large
>> in practice given the I/O hit it's going to involve.

> I think it can be done cleaner in the tar file injection - I've been
> chatting with Heikki offlist about that. Not sure, but I have a
> feeling it does.

One point that I'm particularly interested to see how you'll kluge it
is ensuring that the tarball contains only the desired temp data and not
also the "real" $PGDATA/backup_label, should there be a normal base
backup being done concurrently with the streamed one.

The whole thing just seems too fragile and dangerous to be worth dealing
with given that actual usage will be a corner case. *I* sure wouldn't
trust it to work when the chips were down.

regards, tom lane