Previously I submitted a proposal for adding schemas as a first-class concept on Beam PCollections. The proposal engendered quite a bit of discussion from the community - more discussion than I've seen from almost any of our proposals to date!
Based on the feedback and comments, I reworked the proposal document quite a bit. It now talks more explicitly about the different between dynamic schemas (where the schema is not fully not know at graph-creation time), and static schemas (which are fully know at graph-creation time). Proposed APIs are more fleshed out now (again thanks to feedback from community members), and the document talks in more detail about evolving schemas in long-running streaming pipelines. Please take a look. I think this will be very valuable to Beam, and welcome any feedback. https://docs.google.com/document/d/1tnG2DPHZYbsomvihIpXruUmQ12pHGK0QIvXS1FOTgRc/edit# Reuven
