Sure, I could try! But I definitely need Jarek's help (and the others) on it - so would like to work with Jarek for him to review any changes that I make (and make sure the wordings, definitions, are correct to the intended design).
- Howard On Mon, Feb 7, 2022 at 9:38 AM Ash Berlin-Taylor <[email protected]> wrote: > Agreed! > > Howard: do you fancy trying to create a PR to capture this discusion/the > reasoning in our docs? > > It probably belongs on one of these three pages > > > https://github.com/apache/airflow/blob/main/docs/apache-airflow/concepts/scheduler.rst > > https://github.com/apache/airflow/blob/main/docs/apache-airflow/concepts/dags.rst > > https://github.com/apache/airflow/blob/main/docs/apache-airflow/concepts/timetable.rst > > Cheers, > > Ash > > On Mon, Feb 7 2022 at 09:13:28 +0100, Jarek Potiuk <[email protected]> > wrote: > > Yeah. That discussion actually made me think that probably we need to > explain it better :) > > On Sun, Feb 6, 2022 at 11:10 PM Howard Yoo <[email protected]> wrote: > >> As we discuss this topic, the more and more I get to understand the >> reasons behind all those philosophies behind, so I appreciate the knowledge >> that I gained. >> >> As long as those terms and principles are well described and explained >> without confusion, I believe we are moving to the right direction and >> that’s what matters. >> >> - Howard >> >> Sent from my iPhone >> >> On Feb 6, 2022, at 3:24 PM, Jarek Potiuk <[email protected]> wrote: >> >> >> IMHO It does not really matter if they are the same or not and which one >> is the same. This is actually the beauty of the "abstract" and "vague" >> logical_date. Those are different "concepts" that you use in different >> cases. >> >> The logical date **might** be the same as one of the interval_dates. It's >> just an "abstract" representation of the particular "run_id" - and you >> should not care, because "logical_date" makes sense for some cases, but >> "data_interval_start/end" for other cases. >> >> * If your task is about "data_interval" - by all means use the >> data_interval_start and end. >> * if your task is not about "interval" - use the "logical_date". >> >> That is how I see it at least. By using a different approach when you use >> different cases the users might free their "mental-mapping" - they do not >> have to map the "logical_date" to either "start" or "end". It does not >> matter. but if they process a data interval, they have very clear >> boundaries of ("start" <-> "end") range that they can use without even >> thinking on. how "logical_date" maps to it. >> >> For me - those are completely different cases and they are orthogonal to >> each other (even if some of those values are the same). >> >> J. >> >> On Sun, Feb 6, 2022 at 7:00 PM Howard Yoo <[email protected]> wrote: >> >>> I see, thank you for the info. >>> I didn’t know about the existence of the data_interval_start and end >>> dates. I briefly looked at those definitions, and was wondering… wouldn’t >>> they be equal to the logical dates? I do see those variables mentioned in >>> https://airflow.apache.org/docs/apache-airflow/stable/templates-ref.html, >>> and also see the ds and ts meaning logical dates. In practice, are those >>> dates and timestamps supposed to be the same? >>> >>> Wonder also, if the ‘data_’ prefix would be necessary if airfow would be >>> used to orchestrate far more things in the future (perhaps this may be >>> another thread), but in general, we should have a continuous discussions to >>> further clearly define all those dates for the improved usage of airflow. >>> >>> Howard >>> >>> Sent from my iPhone >>> >>> On Feb 6, 2022, at 11:15 AM, Jarek Potiuk <[email protected]> wrote: >>> >>> >>> We already have `data_interval_start` and `data_interval_end' as fields, >>> and we need something else that can have more "abstract" meaning to apply >>> to the whole run as "single thing". Using interval_date would be a bit >>> ambiguous. >>> >>> "Did you mean start or end actually when you mentioned interval date?" - >>> is the question that I anticipate happening a lot if we mix those. >>> >>> J. >>> >>> >>> >>> On Sun, Feb 6, 2022 at 6:04 PM Howard Yoo <[email protected]> wrote: >>> >>>> Now I can understand why the data_date may not be a perfect fit to >>>> describe the term. >>>> >>>> This is not to be against the logical_date, but what about >>>> ‘interval_date?’ We have the schedule interval, which defines the duration >>>> of the interval (e.g. 1day), so wouldn’t interval start and end date be a >>>> better representation of it rather than the logical date? >>>> >>>> Just want to hear whether that has been brought up already or not. >>>> >>>> Howard >>>> >>>> Sent from my iPhone >>>> >>>> On Feb 6, 2022, at 10:25 AM, Jarek Potiuk <[email protected]> wrote: >>>> >>>> >>>> I wholeheartedly agree with TP on that one. I think while some time >>>> ago "data date" could make sense, Airflow's future is much more than just >>>> processing data intervals. >>>> This is the primary use case and this is where Airflow shines od >>>> course, but one of the good examples of how Airflow is used out there, and >>>> while we are not really encouraging it, there are not only legitimate, but >>>> also something that I hope Airflow will treat as first-time citizens soon >>>> (and it kind of already is with custom timetables). >>>> >>>> Just an example here - for me one of the most eye-opening talks in last >>>> year's Airflow Summit >>>> https://airflowsummit.org/sessions/2021/provision-as-a-service/ >>>> In this talk Cloudflare engineers explain how they manage the >>>> CloudFlare infrastructure using Airflow. >>>> >>>> The "Data date" has no meaning in this case. But the "logical Date" >>>> (which is the vaguest-possible one as TP explained) continues to have one. >>>> This is the "logical date of the infrastructure provisioning". Thanks >>>> to Airflow (as I understand it) Cloudflare is able to re-provision their >>>> services to "yesterday's logical date infrastructure" today - for example. >>>> >>>> That would not fly with "data date". >>>> >>>> J, >>>> >>>>
