String INDEX_BACKUP_TARGETS = "index.backup.targets";

    /** The key of the configuration. e.g. click_log.ndjson,favorite_log.ndjson,search_log.ndjson,user_info.ndjson */
    String INDEX_BACKUP_LOG_TARGETS = "index.backup.log.targets";

    /** The key of the configuration. e.g. 60000 */