It definitely sounds like a nice feature.
The important question is what is the actual importance after you multiply
it by the amount of usage it gets.
For instance, I know that multi gets a bit of usage, but I would guess that
it actually gets very, very little. It might even most of the cases that
you have in mind.
If that is so, how much would an extension to multi actually be used?
On Fri, Aug 16, 2019 at 8:28 PM Michael Han <h...@apache.org> wrote:
> This sounds a nice feature to me as it enables user to do more without
> obvious downside. It could be useful in cases like state management where
> the state is stored in a fine grained approach across multiple zNode,
> instead of in a single zNode.
>
> On Fri, Aug 16, 2019 at 11:52 AM Ted Dunning <ted.dunn...@gmail.com>
> wrote:
>
> > The recent discussion about if/then/else idioms in ZK has raised the
> > thought that it might be nice to have some extended semantics.
> >
> > One version that I could see would be to to extend the current multi-op
> to
> > allow multiple alternatives. The idea would be that there would
> effectively
> > be multiple branches to be tried. The first one that succeeds atomically
> > (all or nothing) would be used. The returned value would need to somehow
> > indicate which alternative succeeded and would need to return any data
> > accessed. The testing of alternatives would also be atomic so it wouldn't
> > be possible for things to change within a single operation.
> >
> > This extension would allow the previous question to be answered like
> this:
> >
> > pick_first {
> > create(...)
> > } {
> > set(...)
> > }
> >
> > (the syntax here is just made up and wouldn't actually be supported ...
> it
> > is just for pseudo code purposes).
> >
> >
> > My theory is that this would be relatively easy to implement based on the
> > current multi operation. Risk due to the change is pretty low given that
> > there is code to copy.
> >
> > My question is whether this would actually have all that much benefit.
> >
> > Does anybody have an opinion on that?
> >
>
