class control_ready_table(threading.Thread): def __init__(self): threading.Thread.__init__(self) self.dbi=MySQL_Interface() def run(self): while True: self.dbi=MySQL_Interface() num=self.dbi.get_line_num('ready_to_get') if num>150*1000: query='select m.fans_num from (' \ 'select fans_num from ready_to_get ' \ 'ORDER BY fans_num limit 50000' \ ') as m order by fans_num desc limit 1' res=self.dbi.select_asQuery(query)[0][0] query='delete from ready_to_get where fans_num<{num}'\ .format(num=res) self.dbi.update_asQuery(query) else: time.sleep(600)