目标标记表更新后的Luigi“未完成相关性错误”

Question

我不会通过两个具有单个相互依赖关系的任务来运行两个SQL语句，但是在此过程中，我遇到了“未填充依赖关系错误”（请参见下文）：

最初，我认为这是由于写入输出时出现问题，但看起来两个任务都已成功写入数据库中的目标表，所以我不确定记录器为什么会抛出此错误？

这是我的简单管道的设置：

class RunSessionsTable(luigi.Task):
    job_name = 'Creating_Sessions_Table' # unique task name or table impacted
    date_param = luigi.DateParameter(default=datetime.date.today()) # today's date

    def generate_job_number(self):
        pacific = pytz.timezone("US/Mountain")
        return pacific.localize(datetime.datetime.now()).strftime('%H')

    def get_target(self):   
        update_id = '{}_{}_{}'.format(self.job_name,self.date_param, self.generate_job_number())
        return ToSnowflake (connection_string = ToSnowflake.connection_string, target_table= self.job_name, update_id = update_id)      

    def output(self):
        return self.get_target().touch()

    def run (self):
        init = ToSnowflake.engine
        conn = init.connect()
        results = conn.execute(sessions_query)
        #conn.close()
        return self.output()
class RunEventsTable(luigi.Task):
    job_name = 'Creating_Events_Table' # unique task name or table impacted
    date_param = luigi.DateParameter(default=datetime.date.today()) # today's date

    def generate_job_number(self):
        pacific = pytz.timezone("US/Mountain")
        return pacific.localize(datetime.datetime.now()).strftime('%H')

    def requires(self):
        return [RunSessionsTable()]

    def get_target(self):   
        update_id = '{}_{}_{}'.format(self.job_name,self.date_param, self.generate_job_number())
        return ToSnowflake (connection_string = ToSnowflake.connection_string, target_table= self.job_name, update_id = update_id)      

    def output(self):
        return self.get_target().touch()

    def run (self):
        init = ToSnowflake.engine
        conn = init.connect()
        results = conn.execute(events_query)
        #conn.close()
        return self.output()


if __name__ == '__main__':
    luigi.build([RunEventsTable()])