[jira] [Commented] (AIRFLOW-5506) Airflow scheduler stuck

["Cruz Fernandez (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/AIRFLOW-5506?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17415750#comment-17415750 ] 

Cruz Fernandez commented on AIRFLOW-5506:
-----------------------------------------

What helped my DAG to run (only one was failing with KubernetesExecutor), was to ERASE airflow database (we had to bring a backup of the airflow variables). Of course, this is not applicable if the history of the jobs is critical for anyone. My PostgreSQL database might be a little bit slow.

> Airflow scheduler stuck
> -----------------------
>
>                 Key: AIRFLOW-5506
>                 URL: https://issues.apache.org/jira/browse/AIRFLOW-5506
>             Project: Apache Airflow
>          Issue Type: Bug
>          Components: scheduler
>    Affects Versions: 1.10.4, 1.10.5, 1.10.6
>            Reporter: t oo
>            Priority: Major
>
> re-post of [https://stackoverflow.com/questions/57713394/airflow-scheduler-stuck] and slack discussion
>  
>  
> I'm testing the use of Airflow, and after triggering a (seemingly) large number of DAGs at the same time, it seems to just fail to schedule anything and starts killing processes. These are the logs the scheduler prints:
> {{[2019-08-29 11:17:13,542] \{scheduler_job.py:214} WARNING - Killing PID 199809
> [2019-08-29 11:17:13,544] \{scheduler_job.py:214} WARNING - Killing PID 199809
> [2019-08-29 11:17:44,614] \{scheduler_job.py:214} WARNING - Killing PID 2992
> [2019-08-29 11:17:44,614] \{scheduler_job.py:214} WARNING - Killing PID 2992
> [2019-08-29 11:18:15,692] \{scheduler_job.py:214} WARNING - Killing PID 5174
> [2019-08-29 11:18:15,693] \{scheduler_job.py:214} WARNING - Killing PID 5174
> [2019-08-29 11:18:46,765] \{scheduler_job.py:214} WARNING - Killing PID 22410
> [2019-08-29 11:18:46,766] \{scheduler_job.py:214} WARNING - Killing PID 22410
> [2019-08-29 11:19:17,845] \{scheduler_job.py:214} WARNING - Killing PID 42177
> [2019-08-29 11:19:17,846] \{scheduler_job.py:214} WARNING - Killing PID 42177
> ...}}
> I'm using a LocalExecutor with a PostgreSQL backend DB. It seems to be happening only after I'm triggering a large number (>100) of DAGs at about the same time using external triggering. As in:
> {{airflow trigger_dag DAG_NAME}}
> After waiting for it to finish killing whatever processes he is killing, he starts executing all of the tasks properly. I don't even know what these processes were, as I can't really see them after they are killed...
> Did anyone encounter this kind of behavior? Any idea why would that happen?
>  
>  



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