The view is automatically updated on an interval. The server docs should have some details on adjusting that. Let me know if you cannot find it.
The problem with knowing "complete" or not is that it needs to be with respect to a change. It's a global ordering problem you might say. Some solve this by retaining changes this particular client 'actor' made, and then applying that result on top of their view query results. That may not work if you want to know if it's complete with respect to another actor.
Also, note that in N1QL, we have a feature, REQUEST_PLUS, that can scope this to the changes that this particular client instance knows about. We need to add some better documentation on that, but if you'd like more information, please let me know.