Renkai opened a new issue, #2444: URL: https://github.com/apache/arrow-rs/issues/2444
**Is your feature request related to a problem or challenge? Please describe what you are trying to do.** <!-- A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] (This section helps Arrow developers understand the context and *why* for this feature, in addition to the *what*) --> My friends wrote a data format [lance](https://github.com/eto-ai/lance) that has interconvertibility with parquet, and I want to make another implementation with Rust. However, they used [EXTENTION](https://github.com/apache/arrow/blob/6cc37cf2d1ba72c46b64fbc7ac499bd0d7296d20/cpp/src/arrow/type_fwd.h#L387) type, it seems has not been implemented in arrow-rs. **Describe the solution you'd like** <!-- A clear and concise description of what you want to happen. --> Let the reader can convert the parquet file with EXTENTION type to Arrow. **Describe alternatives you've considered** <!-- A clear and concise description of any alternative solutions or features you've considered. --> **Additional context** <!-- Add any other context or screenshots about the feature request here. --> Python code I used to generate such a file. ```python # with pyarrow-9.0.0 import pyarrow as pa class UuidType(pa.PyExtensionType): def __init__(self): pa.PyExtensionType.__init__(self, pa.binary(16)) def __reduce__(self): return UuidType, () if __name__ == '__main__': uuid_type = UuidType() print(uuid_type.extension_name) print(uuid_type.storage_type) import uuid storage_array = pa.array([uuid.uuid4().bytes for _ in range(4)], pa.binary(16)) arr = pa.ExtensionArray.from_storage(uuid_type, storage_array) print(arr) table = pa.Table.from_arrays([arr], names=["uuid"]) import pyarrow.parquet as pq pq.write_table(table, "extension_example.parquet") # successfully read and print parquet_table = pq.read_table('extension_example.parquet') print("schema", parquet_table.schema) print("table", parquet_table) ``` Rust code that failed reading ```Rust let input_file_name = "extension_example.parquet"; //https://docs.rs/parquet/19.0.0/parquet/arrow/index.html use arrow::record_batch::RecordBatchReader; use parquet::arrow::{ParquetFileArrowReader, ArrowReader, ProjectionMask}; use std::fs::File; let file = File::open(input_file_name).unwrap(); let mut arrow_reader = ParquetFileArrowReader::try_new(file).unwrap(); let mask = ProjectionMask::leaves(arrow_reader.parquet_schema(), [0]); println!("parquet schema is: {:?}", arrow_reader.parquet_schema()); println!("Converted arrow schema is: {}", arrow_reader.get_schema().unwrap()); ``` error log ``` thread 'tests::test_convert' panicked at 'called `Result::unwrap()` on an `Err` value: ArrowError("Unable to get root as message stored in ARROW:schema: Utf8Error { error: Utf8Error { valid_up_to: 0, error_len: Some(1) }, range: 216..255, error_trace: ErrorTrace([TableField { field_name: \"value\", position: 208 }, VectorElement { index: 0, position: 116 }, TableField { field_name: \"custom_metadata\", position: 92 }, VectorElement { index: 0, position: 48 }, TableField { field_name: \"fields\", position: 40 }, UnionVariant { variant: \"MessageHeader::Schema\", position: 24 }, TableField { field_name: \"header\", position: 24 }]) }")', src/lib.rs:39:77 ``` -- 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]
