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https://issues.apache.org/jira/browse/AIRFLOW-1230?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17048223#comment-17048223
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Qian Yu commented on AIRFLOW-1230:
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The problem is seems to be caused by what you are doing here:
{quote}4. Execute the DAG again:
airflow backfill new_example_bash_operator -s 2017-05-02 -e 2017-05-02
{quote}
After fixing run_before_loop, you should not "backfill". Instead, just Clear it
with Downstream selected and it'll re-run and downstream tasks such as runme_0,
runme_1, etc will re-run too.
"backfill" is not for this purpose. It's for backpopulating missed historical
dates.
Also, a lot has changed since this Jira was reported. We should close this and
open a new one if there are new issues.
> Upstream_failed tasks are not executed when the DAG is restarted after failure
> ------------------------------------------------------------------------------
>
> Key: AIRFLOW-1230
> URL: https://issues.apache.org/jira/browse/AIRFLOW-1230
> Project: Apache Airflow
> Issue Type: Bug
> Components: DAG, DagRun
> Affects Versions: 1.8.0, 1.8.1
> Environment: CentOS release 6.8 (Final)
> Python 2.7.10
> Reporter: Rostislaw Krassow
> Priority: Major
> Attachments: DAG_cleared.gif, DAG_failed.gif,
> DAG_partly_successful.gif, new_example_bash_operator.py
>
>
> The issue is reproducible with Airflow 1.8.0 and 1.8.1.
> Steps to reproduce:
> 1. Use the attached DAG
> [new_example_bash_operator|^new_example_bash_operator.py]. This is a modified
> standard example DAG. The task run_before_loop will fail because it contains
> an error.
> 2. Execute the DAG:
> airflow backfill new_example_bash_operator -s 2017-05-02 -e 2017-05-02
> The task run_before_loop fails as expected. The DAG fails. The screenshot of
> the UI is attached. !DAG_failed.gif!
> All dependend tasks like runme_0, runme_1, runme_2 are going to state
> "upstream_failed".
> 3. Fix the BashOperator in the task run_before_loop (just put "echo 1" as
> bash_command).
> 4. Execute the DAG again:
> airflow backfill new_example_bash_operator -s 2017-05-02 -e 2017-05-02
> Expected behavior:
> Restart of the DAG leads to execution of all failed tasks including
> upstream_failed tasks.
> Observed behavior:
> 1. The failed task is not restarted.
> 2. All dependend tasks are not restarted.
> 3. In order to get the DAG reexecuted its state must be cleared manually:
> airflow clear -f -c new_example_bash_operator -s 2017-05-02 -e 2017-05-02
> !DAG_cleared.gif!
> After the clearance the same DAG can be restarted:
> airflow backfill new_example_bash_operator -s 2017-05-02 -e 2017-05-02
> Then the task run_before_loop is executed. All other tasks still remain in
> state "upstream_failed". !DAG_partly_successful.gif!
> To get all tasks executed their state must be cleared explicitely.
> Conclusion:
> This is a blocker issue for productive usage. We run several dozens of DAGs
> with high number of tasks. In the production environment there are always
> failed tasks. In such cases the restart of the DAG must be simple possible.
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