> If client sets a watcher on a znode by doing a getData operation is it
> guaranteed to get the next change after the value it read, or can a
> change be missed?
The watch is just a notification that the node changed. If you do a getData
on the node, you their might have been more updates on the node.
So yes, you can miss changes.
> In other words if the value it read had zxid z1 and the next update of
> the znode has zxid z2, will the watcher always get the event for the
> change z2?
The watcher will always get an event for zxid z2, but since the watch does
not have the data with it -- it will have to do getdata for the that node.