presto-main/src/main/java/io/prestosql/execution/SqlTaskExecution.java/SchedulingLifespan/nextPlanNode
class SchedulingLifespan:        public void nextPlanNode()
        {
            checkState(!isDone());
            schedulingPlanNodeOrdinal++;
            manager.updateMaxScheduledPlanNodeOrdinalIfNecessary(schedulingPlanNodeOrdinal);
        }