Re: is sync rep stalled?

On Fri, 2010-10-01 at 19:48 +0900, Fujii Masao wrote:

> My intention is to commit the core part of synchronous replication (which would
> be used for every use cases) at first. Then we can implement the
> feature for each
> use case.

I completely agree that we should commit the core part of sync rep, but
the question is: what is that? We both have equally valid "cores".

> I agree that 9.1 should support asynchronous standbys in the same mix, but this
> seems to be extended feature rather than very core.

That is trivial, so no need to exclude that.

> I proposed to implement the "return-immediately" at first because it doesn't
> require standby registration. But if many people think that the "wait-forever"
> is the core rather than the "return-immediately", I'll follow them. We can
> implement the "return-immediately" after that.

I think its fair to say that many people don't like the specific form of
standby registration that has been proposed. I really don't mind if it
exists as an option, but it looks way too complex to me to manage for
realistic systems.

Wait-forever needs to be an option. Nobody actually will wait forever,
so if people select it, they will need some form of clusterware to
control it and I don't want to see people forced to use clusterware.

If people do choose wait-forever, then we could also do standby
registration automatically, to give them something to wait for.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Development, 24x7 Support, Training and Services