Class CheckpointBarrierTracker

  • All Implemented Interfaces:
    Closeable, AutoCloseable

    @Internal
    public class CheckpointBarrierTracker
    extends CheckpointBarrierHandler
    The CheckpointBarrierTracker keeps track of what checkpoint barriers have been received from which input channels. Once it has observed all checkpoint barriers for a checkpoint ID, it notifies its listener of a completed checkpoint.

    Unlike the SingleCheckpointBarrierHandler, the BarrierTracker does not block the input channels that have sent barriers, so it cannot be used to gain "exactly-once" processing guarantees. It can, however, be used to gain "at least once" processing guarantees.

    NOTE: This implementation strictly assumes that newer checkpoints have higher checkpoint IDs.