robertwb commented on pull request #13401: URL: https://github.com/apache/beam/pull/13401#issuecomment-732503837
Fair point. In fact, every operation preserves indexing by singleton, because when you apply to the whole input you get the whole output. But `df` being logically partitioned by `X` is different from being the result of applying partitioning `X` to `df`. Sometimes we need the former (e.g. when grouping), sometimes the latter (e.g. when considering co-partitionings). So far we've only really used `Nothing`, `Index`, and `Singleton` so we should be OK, but care needs to be applied if we ever start to use the others. ---------------------------------------------------------------- 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]
