chenkovsky commented on PR #14057: URL: https://github.com/apache/datafusion/pull/14057#issuecomment-2646850170
> > when I save a table to csv, it will also save rowid into csv. no system will do like this. > > My problem is with this statement. I don't think there's a universal definition and use case for "system columns". Spark has one. Postgres has another. Our system has another. first, the assumption of projection is not correct in dataframe, right? I agree with you. there's no universal definition. But If I'm a logical plan implementer. in this PR, if I want to support system column, I can create another logical plan. If I don't want to support system column. I even don't need to take care of what is system column. But in #14362 , If I want to support system column, it's easy, because it's propagated automatically, but If I don't want to support system column, I have to take care to erase it, e.g. CopyTo. at least this is counterintuitive for me. Why do I have to take care of something I don't support? -- 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. To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
