Hi all,
I'm new to Airflow, and I'm looking for someone to clarify the expected behavior of running a backfill with regard to previously successful tasks. When I run a backfill on 1.8.0, tasks that were previously run successfully are re-run for me. Is it expected that backfills re-run all tasks, even those that were marked as successful? For reference, the command I'm running is `airflow backfill -s 2017-04-01 -e 2017-04-03 Tutorial`. I wasn't able to find anything in the documentation to indicate either which way. Some brief research revealed that invoking backfill was meant at one point to "fill in the blanks", which I interpret to mean "only run tasks that were not completed successfully". On the contrary, the code *does* seem to explicitly set all task instances for a given DAGRun to SCHEDULED (see [AIRFLOW-910][1] and https://github.com/apache/incubator-airflow/pull/2107/files#diff-54a57ccc2c8e73d12c812798bf79ccb2R1816). Apologies for such a fundamental question, just want to make sure I'm not missing something obvious here. Can someone clarify? Thanks, Chris Fei Links: 1. https://issues.apache.org/jira/browse/AIRFLOW-910
