Re: Add timeline to partial WAL segments

On Wed, Dec 12, 2018 at 1:13 PM David Steele <david(at)pgmasters(dot)net> wrote:
> On 12/11/18 11:06 PM, Robert Haas wrote:
> > On Wed, Dec 12, 2018 at 11:29 AM Michael Paquier <michael(at)paquier(dot)xyz> wrote:
> >> I really don't think that it is a good idea to link a future timeline
> >> within a segment which includes in its name a direct reference to its
> >> current timeline. Also I don't buy much the argument that those
> >> segments are a nuisance as well all the time. They may be for some
> >> tools, however not for others depending on the archiving strategy
> >> (distributed locations for example), and if they are a problem for your
> >> deployments, why not just discarding them within the archive command and
> >> be done with them?
> >
> > -1. Writing an archive_command already requires a PhD in
> > PostgreSQL-ology. The very last thing we should do is invent even
> > more ways for an archive command to be subtly wrong.
>
> The point here is to make archive commands simpler. As it is, the
> various backup tools are going to need to find ways to deal with the
> problem, and each solution will be different.
>
> The goal is to come up with a solution that works and that all archive
> commands can use, rather than each one rolling their own solution.

I understand. I'm more or less agreeing with you. Actually, I'm not
really sure whether your particular proposal is the best way of
handling this, but I disagree with Michael's suggestion that we should
just throw responsibility back on archive_command.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company