public static function reset_backup_ids_cached() {
        // Reset the ids cache.
        $cachetoadd = count(self::$backupidscache);
        self::$backupidscache = array();
        self::$backupidscachesize = self::$backupidscachesize + $cachetoadd;
        // Reset the exists cache.
        $existstoadd = count(self::$backupidsexist);
        self::$backupidsexist = array();
        self::$backupidsexistsize = self::$backupidsexistsize + $existstoadd;
    }