}
        for (Thread th : threads) {
            th.join();
        }
        assertEquals(num, count.get());
        assertEquals(num, valueSet.size());

        Set<String> valueSet2 = Collections.synchronizedSet(new HashSet<>());
        threads = new Thread[threadNum];
        ESSourceReader reader2 = new ESSourceReader(client, settings, indexName);
        reader2.setScrollSize(100);