long start = System.currentTimeMillis();
MergeSortHelper.output("Making queue of sorted queues ...");
Queue<IBigQueue> queueOfSortedQueues = new LinkedList<IBigQueue>();
MergeSortHelper.makeQueueOfSortedQueues(srcBigQueue, maxInMemSortNumOfItems, queueOfSortedQueues);
// have done with source queue, empty it and delete back data files to save disk space
srcBigQueue.removeAll();
srcBigQueue.close();
MergeSortHelper.output("Merging and sorting the queues ...");
MergeSortHelper.mergeSort(queueOfSortedQueues, maxMergeSortWays);
long end = System.currentTimeMillis();