mapleFU commented on issue #6735: URL: https://github.com/apache/arrow-rs/issues/6735#issuecomment-3138655493
I noticed that in parquet internal there're multiple kinds of evolution: 1. Without any real cast. This happens on type changes (1) Like `Utf8 -> Utf8View`, `List -> ListView` they're store same in parquet (2) Int8/Int16 -> Int32. Parquet stores at least int32 type. 2. Need some casting? Similiar to (1) but might need some explicit cast. ( Schema Adapters) 3. New default / Null column 4. New projection/Expression added. Which might need some expression added. In fact a reader can expose "NULL" I think (3)(1) might able to push in a layer in parquet/arrow, but (2)(4) might need others ( Maybe iceberg-rust or datafusion can be a good example?) -- 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...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
