soyrice commented on a change in pull request #11415: [BEAM-9650] Cleanup documentation on side inputs patterns URL: https://github.com/apache/beam/pull/11415#discussion_r408434733
########## File path: website/src/documentation/patterns/side-inputs.md ########## @@ -50,25 +50,25 @@ For instance, the following code sample uses a `Map` to create a `DoFn`. The `Ma ## Slowly updating side input using windowing -You can read side input pcollection periodically into distinct windows. -Later, when you apply side input to your main input, windows will be matched automatically 1:1. -This way, you can guarantee side input consistency on the duration of the single window. - -To do this, you can utilize PeriodicSequence PTransform that will generate infinite sequence -of elements with some real-time period: +You can read side input data periodically into distinct PCollection windows. +Later, when you apply the side input to your main input, each main input +window is automatically matched to a single side input window. +This guarantees side input consistency on the duration of the single window, +meaning that each window on main input side will be matched to a single +version of side input data. + +To do this, you can utilize a combination of PeriodicSequence/PeriodicImpulse +PTransforms that will generate infinite sequence of elements with some real-time +period and SDF Read operation or similar to read data into side input +periodically: 1. Use the PeriodicImpulse transform to generate windowed periodic sequence. - a. MAX_TIMESTAMP can be replaced with some closer boundary if you want to stop generating elements at some point. - 1. Read data using Read operation triggered by arrival of PCollection element. Review comment: On a second look, I think it's redundant to say "Read data using a Read operation" - maybe we can say something like "Read data when a PCollection element arrives" ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
