final RangeQueryBuilder rangeQuery = QueryBuilders.rangeQuery(field);
        final BytesRef min = termRangeQuery.getLowerTerm();
        if (min != null) {
            if (termRangeQuery.includesLower()) {
                rangeQuery.gte(min.utf8ToString());
            } else {
                rangeQuery.gt(min.utf8ToString());
            }
        }

        final FessConfig fessConfig = ComponentUtil.getFessConfig();

        final StringBuilder resultBuf = new StringBuilder();

        // clean up
        final QueryBuilder queryBuilder = QueryBuilders.rangeQuery(fessConfig.getIndexFieldExpires()).to("now");
        try {
            searchEngineClient.deleteByQuery(fessConfig.getIndexDocumentUpdateIndex(), queryBuilder);

        } catch (final Exception e) {

        queryBuilder.must(QueryBuilders.termQuery(FieldNames.KINDS, SuggestItem.Kind.QUERY.toString()));
        queryBuilder.mustNot(QueryBuilders.existsQuery(FieldNames.READING_PREFIX + "1"));
        queryBuilder.must(QueryBuilders.rangeQuery(FieldNames.QUERY_FREQ).gte(queryFreqThreshold));
        if (!tags.isEmpty()) {
            queryBuilder.must(QueryBuilders.termsQuery(FieldNames.TAGS, tags));
        }
        if (!roles.isEmpty()) {