[GitHub] [incubator-dolphinscheduler] samz406 commented on issue #2540: [BUG] update crontab task error (更新定时任务时错误)

[GitBox <gi...@apache.org>]

samz406 commented on issue #2540:
URL: https://github.com/apache/incubator-dolphinscheduler/issues/2540#issuecomment-620070564


   hello
     According to your screenshot, the short time you choose is 2020-04-27 23:56:00 to 2020-04-27 23:56:02
   cron expression is 0 0 * * *? *, It can be judged that the cron expression is executed once every hour. Then, according to your start time, the next execution time should be 2020-04-28 00:00:00, and your end time period is 2020-04-27 23:56:02, which is less than the next execution time . So adding Quartz job will fail. That is, the online failed.
   
   **Solution**
   1 You can adjust the end time period. Just include the next execution time of cron within the start and end time period.
   
   2 When modifying the timing, set the "execution time" button to calculate the next five execution times. If there is data, the timing setting is correct, otherwise there is a problem with the timing setting.
   
   
   根据你的截图，你选的时间短是2020-04-27 23:56:00 到 2020-04-27 23:56:02 
   cron 表达式为 0 0 * * * ? *,可以判断cron表达式是一小时执行一次。如果按照你的的开始时间，下一次执行执行时间应该是2020-04-28 00:00:00，而你的结束时间段是 2020-04-27 23:56:02 ，小于下一次执行时间。所以添加Quartz job就会失败。也就是上线失败。
   
   **解决办法**
   1 你可以调整结束时间段。只要要包含cron下一次执行时间在起止时间段内。
   
   2 在修改定时，单击“执行时间”按钮，可以计算接下来五次执行时间，如果有数据那么定时设置正确，否则定时设置就有问题。
   
   ![image](https://user-images.githubusercontent.com/3055810/80392079-42ebf300-88e1-11ea-897c-7043dae65caa.png)
   
   
   
   
   


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