.setFetchSource(false).setSize(fessConfig.getPageScoreBoosterMaxFetchSizeAsInteger()).execute().actionGet(requestTimeout);
        return Arrays.stream(response.getHits().getHits()).map(SearchHit::getId).toArray(n -> new String[n]);
    };

    protected Function<Map<String, Object>, Long> requestHandler = params -> {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();