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

    /**
     * A function to handle requests.
     */
    protected Function<Map<String, Object>, Long> requestHandler = params -> {

                .addSort("timestamp", SortOrder.ASC)
                .execute()
                .actionGet(fessConfig.getIndexSearchTimeout());

        final SearchHit[] hits = searchResponse.getHits().getHits();
        if (hits.length == 0) {
            return "No log notifications.";
        }

        final List<LogNotificationEvent> events = new ArrayList<>();
        final List<String> docIds = new ArrayList<>();