org.apache.flink.runtime.checkpoint

Interface OperatorStateRepartitioner<T>

All Known Implementing Classes:

MappingBasedRepartitioner, RoundRobinOperatorStateRepartitioner

@Internal
public interface OperatorStateRepartitioner<T>

Interface that allows to implement different strategies for repartitioning of operator state as parallelism changes.

Method Summary

Modifier and Type	Method and Description
List<List<T>>	repartitionState(List<List<T>> previousParallelSubtaskStates, int oldParallelism, int newParallelism)

Method Detail

repartitionState

List<List<T>> repartitionState(List<List<T>> previousParallelSubtaskStates,
                               int oldParallelism,
                               int newParallelism)

Parameters:

previousParallelSubtaskStates - List with one entry of state handles per parallel subtask of an operator, as they have been checkpointed.

oldParallelism - The parallelism before we start redistribution.

newParallelism - The parallelism that we consider for the state redistribution. Determines the size of the returned list.

Returns:

List with one entry per parallel subtask. Each subtask receives now one collection of states that build of the new total state for this subtask.