/** The key of the configuration. e.g. MT_ */
    String QUERY_GSA_META_PREFIX = "query.gsa.meta.prefix";

    /** The key of the configuration. e.g. charset */
    String QUERY_GSA_INDEX_FIELD_CHARSET = "query.gsa.index.field.charset";

    /** The key of the configuration. e.g. content_type */
    String QUERY_GSA_INDEX_FIELD_content_type_ = "query.gsa.index.field.content_type.";