> So, we end up with something like this:
>    A/B
>    A/C/D-0
>    A/C/D-1

While people are thinking, let me ask this more explicitly: how hard
would it be to add multi-step atomic actions to Zookeeper?

The interest is specifically to:

1) Avoid intermediate states to be persisted when the client creating
the state crashes

2) Avoid intermediate states to be seen while a coordination structure
is being put in place

I understand that there are tricks which may be used to avoid some of
the related problems by dealing with locks, liveness nodes, and "side
services" which monitor and clean up the state, but it'd be fantastic
to have some internal support in Zookeeper to make these actions
simpler and less error prone.  It feels like, given Zookeeper
guarantees, it shouldn't be too hard to extend the protocol to offer
some basic-level operation grouping (e.g. multi-create and
multi-delete, at least).

Does that make sense?

Gustavo Niemeyer

Reply via email to