presto-main/src/main/java/io/prestosql/execution/SqlStageExecution.java/SqlStageExecution/schedulingComplete
class SqlStageExecution:    public synchronized void schedulingComplete(PlanNodeId partitionedSource)
    {
        for (RemoteTask task : getAllTasks()) {
            task.noMoreSplits(partitionedSource);
        }
        completeSources.add(partitionedSource);
    }