int num = 10000;

        addDocument(indexName, client, num);

        ESSourceReader reader = new ESSourceReader(client, settings, indexName);
        reader.setScrollSize(1000);
        int count = 0;
        Set<String> valueSet = Collections.synchronizedSet(new HashSet<>());
        Map<String, Object> source;
        while ((source = reader.read()) != null) {

        }

        return queue.poll();
    }

    @Override
    public void close() {
        isFinished.set(true);
        queue.clear();
    }

    public void setScrollSize(final int scrollSize) {
        this.scrollSize = scrollSize;
    }

    public void setLimitOfDocumentSize(final long limitOfDocumentSize) {
        if (logger.isInfoEnabled()) {

            final ESSourceReader reader = new ESSourceReader(ComponentUtil.getSearchEngineClient(), suggester.settings(),
                    fessConfig.getIndexDocumentSearchIndex());
            reader.setScrollSize(fessConfig.getSuggestSourceReaderScrollSizeAsInteger());
            reader.setLimitDocNumPercentage(fessConfig.getSuggestUpdateContentsLimitNumPercentage());

    public void setScrollTimeout(final int scrollTimeout) {
        this.scrollTimeout = scrollTimeout;
    }

    public int getScrollSize() {
        return scrollSize;
    }

    public void setScrollSize(final int scrollSize) {
        this.scrollSize = scrollSize;
    }

    protected static class EsTimestampConverter implements Converter {

        CountDownLatch latch = new CountDownLatch(1);
        AtomicInteger numObInputDoc = new AtomicInteger(0);
        ESSourceReader reader = new ESSourceReader(client, suggester.settings(), indexName);
        reader.setScrollSize(1000);

        suggester.indexer().indexFromDocument(() -> reader, 1000, 100).then(response -> {
            numObInputDoc.set(response.getNumberOfInputDocs());
            latch.countDown();
        }).error(t -> {