Re: multimaster (was: Slightly OT.)

On Fri, Jun 01, 2007 at 08:40:13PM +0200, Alexander Staubo wrote:
> On 6/1/07, Andrew Sullivan <ajs(at)crankycanuck(dot)ca> wrote:
> >These are all different solutions to different problems, so it's not
> >surprising that they look different. This was the reason I asked,
> >"What is the problem you are trying to solve?"
>
> You mean aside from the obvious one, scalability?

Why is that the "obvious one"? If that's your problem, say so. I
have different problems. I don't need 30 back end machines to keep
my website running. Something obvious in one context is a misfeature
of pointless complication in another.

> appear a solution that could enable a database to scale horizontally
> with minimal impact on the application. In light of this need, I think
> we could be more productive by rephrasing the question "how/when we
> can implement multimaster replication?" as "how/when can we implement
> horizontal scaling?".

Indeed, this may well be a different problem. In fact, if what you
want is "to scale horizontally with minimal impact on the
application", I encourage you to go out and buy the first database
replication system that will actually do that for you. Not the one
that _tells_ you they can, the one that actually does.

I agree that horizontal scaling is a desirable feature, but I don't
think it obvious that multimaster replication, whatever that means,
is the thing that will solve that problem.

> I would love to see a discussion about how PostgreSQL could address
> these issues.

Well, a good start would be to list what exactly you do and do not
mean by horizontal scaling: what is the behaviour under various
scenarios. That's a good way to list at least what the problem is.
(Your mail was a good start, but only a start. Is RI required across
nodes? Why not? Why? What is allowed to break? &c.)

A
--
Andrew Sullivan | ajs(at)crankycanuck(dot)ca
The fact that technology doesn't work is no bar to success in the marketplace.
--Philip Greenspun