presto-main/src/main/java/io/prestosql/execution/NodeTaskMap.java/NodeTasks/setPartitionedSplitCount
class NodeTasks:            public synchronized void setPartitionedSplitCount(int partitionedSplitCount)
            {
                if (partitionedSplitCount < 0) {
                    int oldValue = localPartitionedSplitCount.getAndSet(0);
                    nodeTotalPartitionedSplitCount.addAndGet(-oldValue);
                    throw new IllegalArgumentException("partitionedSplitCount is negative");
                }

                int oldValue = localPartitionedSplitCount.getAndSet(partitionedSplitCount);
                nodeTotalPartitionedSplitCount.addAndGet(partitionedSplitCount - oldValue);
            }