Hi, it's my first post here but I'm a group reader for a while, so thank you for sharing the knowledge!
I've been using Beam/Scio on Dataflow for about a year, mostly for stream processing from unbounded source like PubSub. During my daily work I found that built-in windowing is very generic and provides reach watermark/late events semantics but there are a few very annoying limitations, e.g: - both side of the join must be defined within compatible windows - for fixed windows, elements close to window boundaries (but in different windows) won't be joined - for sliding windows there is a huge overhead if the duration is much longer than offset I would like to ask you to review a few "join/windowing patterns" with custom stateful ParDos, not so generic as Beam built-ins but perhaps better crafted for more specific needs. I published code with tests, feel free to comment as GitHub issues or on the mailing list. The event time processing with watermarks is so demanding that I'm almost sure that I overlooked many important corner cases. https://github.com/mkuthan/beam-examples If you think that the examples are somehow useful I'll be glad to write blog post with more details :) Marcin
