概念
文档1中有如下几句话:
The first DAG Run is created based on the minimum start_date for the tasks in your DAG. Subsequent DAG Runs are created by the scheduler process, based on your DAG’s schedule_interval, sequentially.
If you run a DAG on a schedule_interval of one day, the run with execution_date 2019-11-21 triggers soon after 2019-11-21T23:59.
Let’s Repeat That, the scheduler runs your job one schedule_interval AFTER the start date, at the END of the period.
其中start_date:调度计划开始时间,静态值
schedule_interval:调度间隔时间
execution_date :任务具体执行时间,动态值
意思就是说调度任务执行时间应该是start_date+schedule_interval。此外,当任务执行过后,start_date配置便不再生效。
airflow会在start_date之后,在满足schedule_interval的前提之下,到达第一个execution_date,但并不会立刻执行,等到达下一个时间点才开始执行任务。如下图所示: