john-bodley opened a new pull request, #25290: URL: https://github.com/apache/airflow/pull/25290
<!-- 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 an 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/ --> I was trying to decipher when exactly a DAG run associated with a given `ds` would run, i.e., at midnight (00:00) or midnight (24:00). Per the docs, > A DAG run is usually scheduled after its associated data interval has ended, to ensure the run is able to collect all the data within the time period. In other words, a run covering the data period of 2020-01-01 generally does not start to run until 2020-01-01 has ended, i.e. after 2020-01-02 00:00:00. and observing DAG runs it seems like these DAG runs occur at the end of said day rather than the beginning. This PR updates the documentation—hopefully I got this correct—to: 1. Remove confusion. As reported in [this](https://en.wikipedia.org/wiki/12-hour_clock#Confusion_at_noon_and_midnight) Wikipedia article there's some ambiguity around what day midnight is associated with and thus I felt being explicit—via the use of a 24 hour clock—would help clarify. 2. Address inaccuracies/inconsistencies, i.e., some DAG presets state "midnight" whereas others reference the morning— "midnight on Sunday morning". Additionally I think "... at the _beginning_ of the hour" should be "... at the _end_ of the hour" assuming these windows operate in a consistent manner. --- **^ 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 changes, an 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 a newsfragment file, named `{pr_number}.significant.rst` or `{issue_number}.significant.rst`, in [newsfragments](https://github.com/apache/airflow/tree/main/newsfragments). -- 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]
