valkum commented on issue #17445: URL: https://github.com/apache/datafusion/issues/17445#issuecomment-3406691900
Thanks @duongcongtoai. If I understand the arrow c++ impl correctly, it does not concatenate on reading. You can explicitly _merge_ dicts for a chunked array using `DictionaryUnifier::UnifyChunkedArray`. See [tests](https://github.com/apache/arrow/blob/a53ebde62053a6fc791fc7d8a8280167d5f3fda7/cpp/src/arrow/array/array_dict_test.cc#L1652C1-L1652C48) for examples. `build_extend_dictionary` is in the direct call chain of `ArrayReader::consume_batch for ListArrayReader` via `MutableArrayData::new` -> `MutableArrayData::with_capacity`. The respective PR that added the concat to arrow-rs is https://github.com/apache/arrow-rs/pull/15. This means that arrow-rs currently can inflate the dictionaries when reading and writing a parquet file without any other ops. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
