hi,team:

    my dag is 1 minute schedule,one parts dag state is success,but tasks state is not yet started in a dag:

![image](https://user-images.githubusercontent.com/41068725/116344664-357d8780-a819-11eb-8010-c746ffdfdbcc.png)


   how can to fix it?
airflow/settings.py
# ma
        # no 
        # of 
        max_overflow = conf.getint('core', 'SQL_ALCHEMY_MAX_OVERFLOW', fallback=10)
        # Th
        # wh
        # co
        # po
        pool_recycle = conf.getint('core', 'SQL_ALCHEMY_POOL_RECYCLE', fallback=1800)
        # Ch
        # Ty
        # of som
        # More i
        # https:
        pool_pre_ping = conf.getboolean('core', 'SQL_ALCHEMY_POOL_PRE_PING', fallback=True)
        log.debug(
            "settings.prepare_engine_args(): Using pool settings. pool_size=%d, max_overflow=%d, "
            "pool_recycle=%d, pid=%d",
            pool_size,
            max_overflow,
            pool_recycle,
            os.getpid(),
        )
        engine_args['pool_size'] = pool_size
        engine_args['pool_recycle'] = pool_recycle
        engine_args['pool_pre_ping'] = pool_pre_ping
        engine_args['max_overflow'] = max_overflow
    return engine_args
def dispose_orm():