kylebarron commented on issue #957:
URL:
https://github.com/apache/datafusion-python/issues/957#issuecomment-2555859437
In this case it's an issue with writing the Parquet file, not reading, which
you can see if you try to read the file back with pyarrow:
```py
In [23]: import pyarrow.parquet as pq
In [24]: pq.read_schema(FILENAME)
Out[24]:
array: list<item: float>
child 0, item: float
```
In this case it's actually because the _writing_ side doesn't correctly
propagate the Arrow metadata either.
Here's how `pyarrow.parquet` correctly propagates the Arrow schema within
the Parquet metadata:
```py
In [32]: pq.write_table(table, "test.parquet")
In [33]: meta2 = pq.read_metadata('test.parquet')
In [34]: meta2.metadata
Out[34]: {b'ARROW:schema':
b'/////6gAAAAQAAAAAAAKAAwABgAFAAgACgAAAAABBAAMAAAACAAIAAAABAAIAAAABAAAAAEAAAAEAAAAzP///wAAARAUAAAAIAAAAAQAAAABAAAALAAAAAUAAABhcnJheQAGAAgABAAGAAAAAgAAABAAFAAIAAYABwAMAAAAEAAQAAAAAAABAxAAAAAcAAAABAAAAAAAAAAEAAAAaXRlbQAABgAIAAYABgAAAAAAAQA='}
```
However there's no embedded Arrow schema in the Parquet file written by
DataFusion:
```
In [35]: df_table.write_parquet(FILENAME)
In [36]: meta = pq.read_metadata(FILENAME)
In [37]: meta.metadata # None
```
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