Re: Built-in Raft replication

* Greg Sabino Mullane <htamfids(at)gmail(dot)com> [25/04/15 18:08]:

> > If anyone is working on Raft already I'd be happy to discuss
> > the details. I am fairly new to the PostgreSQL hackers ecosystem
> > so cautious of starting work in isolation/knowing there is no
> > interest in accepting the feature into the trunk.
> >
>
> Putting aside the technical concerns about this specific idea, it's best to
> start by laying out a very detailed plan of what you would want to change,
> and what you see as the costs and benefits. It's also extremely helpful to
> think about developing this as an extension. If you get stuck due to
> extension limitations, propose additional hooks. If the hooks will not
> work, explain why.
>
> Getting this into core is going to be a long, multi-year effort, in which
> people are going to be pushing back the entire time, so prepare yourself
> for that. My immediate retort is going to be: why would we add this if
> there are existing tools that already do the job just fine? Postgres has
> lots of tasks that it is happy to let other programs/OS
> subsystems/extensions/etc. handle instead.

I had hoped I explained why external state providers can not
provide the same seamless UX as built-in ones. The key idea is to
have a built-in configuration management, so that adding and
removing replicas does not require changes in multiple disjoint
parts of the installation (server configurations, proxies,
clients).

I understand and accept that it's a multi-year effort, but I do
not accept the retort - my main point is that external tools
are not a replacement, and I'd like to reach consensus on that.

--
Konstantin Osipov, Moscow, Russia