Re: [HACKERS] Replication documentation addition

Joshua D. Drake wrote:
> Bruce Momjian wrote:
> > Jim C. Nasby wrote:
> >> On Wed, Oct 25, 2006 at 08:42:07PM -0400, Bruce Momjian wrote:
> >>> Jim C. Nasby wrote:
> >>>> Something else worth doing though is to have a paragraph explaining why
> >>>> there's no built-in replication. I don't have time to write something
> >>>> right now, but I can do it later tonight if no one beats me to it.
> >>> I thought that was implied in the early paragraph about why there are
> >>> many solutions.
> >> I think we should explicitely spell it out, especially considering how
> >> many times people ask about it. How about...
> >>
> >> This multitude of choices is why PostgreSQL does not ship with a
> >> replication solution by default; any bundled solution would only
> >> satisfy a subset of replication needs.
> >
> > The problem is that we do have some solutions in our code, like doing
> > data partitioning in the application, warm standby, or using a shared
> > disk for failover, so how do we spell that out? I say there are
> > multiple solutions, but I don't see how I can say that all are external
> > and not included.
>
> None of those are replication solutions. So I would have to agree with
> Jim here.
>
> This isn't about what people do with their app, so that is not relevant.
>
> Warm standby is PITR which is a backup and recovery solution. It does
> not include a failover solution and is *not* replication. It technically
> does not provide an HA solution either as it will be almost always
> farther behind than a replication solution.
>
> Shared disk for failover could be used by anything it isn't special to a
> replication scenario it is standard for many HA.

The section is no longer titled only "replication", but is now
"Failover, Replication, Load Balancing, and Clustering Options", so it
is more a catch-all, and hence saying nothing is included doesn't make
sense. You could say no "replication" is included, but replication is
only one part of the section, so where do you put that, and why is it
worth it?

--
Bruce Momjian bruce(at)momjian(dot)us
EnterpriseDB http://www.enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +