potiuk opened a new pull request #21362: URL: https://github.com/apache/airflow/pull/21362
The scheduler job performs scheduling after lockign the DagRun for writing. This should prevent from modifying DagRun by another scheduler or "mini-scheduler" run after task is completed. However there is apparently one more case where the DagRun is being locked by "Task" processes - namely when task throws AirflowRescheduleException. In this case a new "TaskReschedule" entity is inserted into the database and it also performs lock on the DagRun (because TaskReschedule has "DagRun" relationship. This PR modifies handling the AirflowRescheduleException to obtain the very same DagRun lock before it attempts to insert TaskReschedule entity. Seems that TaskReschedule is the only one that has this relationship so likely all the misterious SchedulerJob deadlock cases we experienced might be explained (and fixed) by this one. It is likely that this one: * Fixes: #16982 * Fixes: #19957 <!-- Thank you for contributing! Please make sure that your code changes are covered with tests. And in case of new features or big changes remember to adjust the documentation. Feel free to ping committers for the review! In case of existing issue, reference it using one of the following: closes: #ISSUE related: #ISSUE How to write a good git commit message: http://chris.beams.io/posts/git-commit/ --> --- **^ Add meaningful description above** Read the **[Pull Request Guidelines](https://github.com/apache/airflow/blob/main/CONTRIBUTING.rst#pull-request-guidelines)** for more information. In case of fundamental code change, Airflow Improvement Proposal ([AIP](https://cwiki.apache.org/confluence/display/AIRFLOW/Airflow+Improvements+Proposals)) is needed. In case of a new dependency, check compliance with the [ASF 3rd Party License Policy](https://www.apache.org/legal/resolved.html#category-x). In case of backwards incompatible changes please leave a note in [UPDATING.md](https://github.com/apache/airflow/blob/main/UPDATING.md). -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
