title: airflow task INFO - Task exited with return code -9
body: <p>i am using big pandas dataframe and while task run for 30-40 min . in the middle of heavy computation i got this message:-</p>
  
  <pre><code>-bash-4.2$ tail -f  /home/app/airflow/logs/report_dag_for_new_metrics/first_pass_yield_metrics/2020-05-21T15\:41\:46.689070+00\:00/2.log 
  [2020-05-26 05:05:17,427] {logging_mixin.py:95} INFO - sort columns in data frame for merge ['product_id', 'type', 'created_date']
  [2020-05-26 05:05:24,153] {logging_mixin.py:95} INFO -        product_id type              created_date
  0  00000346333824    I                2020-04-17
  1  00000346333824    U  2020-04-25T21:53:58.551Z
  2  00000346333824    U  2020-04-25T22:07:03.581Z
  3  00000346333824    U  2020-05-20T04:32:16.581Z
  4  00000346357646    I                2020-04-17
  [2020-05-26 05:05:24,173] {logging_mixin.py:95} INFO - (58582, 1206)
  [2020-05-26 05:05:24,194] {logging_mixin.py:95} INFO - 23618
  [2020-05-26 05:17:17,260] {logging_mixin.py:95} INFO - [2020-05-26 05:17:17,259] {local_task_job.py:105} INFO - Task exited with return code -9
  </code></pre>
  
  <p>any help , airflow community also doesn't say much about code 9 . saw issues related to code 6.</p>