[GitHub] [arrow] endremborza opened a new issue, #34782: empty table changes datatpye from ns to us

["endremborza (via GitHub)" <gi...@apache.org>]

endremborza opened a new issue, #34782:
URL: https://github.com/apache/arrow/issues/34782

   ### Describe the bug, including details regarding any error messages, version, and platform.
   
   Hello!
   
   I don't know if this is specific to python but seems quite straightforward. I didn't look into it very deeply but its easy to reproduce so I thought I'd post it.
   
   ```python
   import pyarrow as pa
   import pyarrow.parquet as pq
   
   pa.__version__
   ```
   > '11.0.0'
   
   ```python
   pt = pa.Table.from_pylist([], pa.schema([("d", pa.timestamp("ns"))]))
   
   pt
   ```
   ```
   pyarrow.Table
   d: timestamp[ns]
   ----
   d: [[]]
   ```
   
   ```python
   pq.write_table(pt, "_.p")
   
   pq.read_table("_.p")
   ```
   
   ```
   pyarrow.Table
   d: timestamp[us]
   ----
   d: [[]]
   ```
   
   
   very interestingly if I use pandas, it goes the other way around
   
   ```python
   import pandas as pd
   
   pt = pa.Table.from_pandas(pd.DataFrame({"d": pd.date_range("2023-01-01", "2023-01-02")}))
   
   pt
   ```
   
   ```
   pyarrow.Table
   d: timestamp[ns]
   ----
   d: [[2023-01-01 00:00:00.000000000,2023-01-02 00:00:00.000000000]]
   ```
   
   ```python
   pq.write_table(pt, "_.p")
   
   pq.read_table("_.p")
   ```
   
   ```
   pyarrow.Table
   d: timestamp[us]
   ----
   d: [[2023-01-01 00:00:00.000000,2023-01-02 00:00:00.000000]]
   ```
   
   
   ### Component(s)
   
   Python


-- 
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: issues-unsubscribe@arrow.apache.org.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org