Hi Guys,
I am trying to understand how state transitions work in Helix. My understanding is that once a controller decides to perform a state transition, this information is conveyed to the relevant participants. A method corresponding to the transitions is invoked on the state model object at the participant corresponding to the partition whose state needs to change.
When state transitions involve data movement, performing the actual transition at the participant is not an instantaneous activity. So while the invocation of the transition function triggers the actual data movement, is there a way for the participant to indicate that the transition is complete? What is the state of the system while a transition is being effected on the cluster?
I am guessing Helix needs to model the state of an in-progress transition to correctly provide throttling guarantees on the cluster.
Where should I be looking in the code to understand how this works? Thanks, Vinayak
