[PyIceberg] Cannot read Timestamp Nanoseconds in V3 tables

[sargarass]

Apache Iceberg version

1.9.2 (latest release)

Query engine

None

Please describe the bug 🐞

PyIceberg Master 5e0499c934c5d5a5869c85452f0d586ef4c09c83

When reading a V3 table containing nanosecond timestamps, PyIceberg attempts to downcast them to microseconds but fails. This operation succeeds when the table column is defined as a microsecond timestamp, even though the underlying Parquet files store both cases as nanosecond timestamps.

virtual-env/bin/python create_table.py                                                                                                                                                                                                                         
Iceberg does not yet support 'ns' timestamp precision. Downcasting to 'us'.
Iceberg does not yet support 'ns' timestamp precision. Downcasting to 'us'.
Traceback (most recent call last):
  File "playground/create_table.py", line 19, in <module>
    print(tbl.scan(limit=3).to_arrow())
          ~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/table/__init__.py", line 1978, in to_arrow
    ).to_table(self.plan_files())
      ~~~~~~~~^^^^^^^^^^^^^^^^^^^
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/io/pyarrow.py", line 1614, in to_table
    first_batch = next(batches)
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/io/pyarrow.py", line 1665, in to_record_batches
    for batches in executor.map(batches_for_task, tasks):
                   ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/concurrent/futures/_base.py", line 619, in result_iterator
    yield _result_or_cancel(fs.pop())
          ~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "/usr/lib/python3.13/concurrent/futures/_base.py", line 317, in _result_or_cancel
    return fut.result(timeout)
           ~~~~~~~~~~^^^^^^^^^
  File "/usr/lib/python3.13/concurrent/futures/_base.py", line 456, in result
    return self.__get_result()
           ~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3.13/concurrent/futures/_base.py", line 401, in __get_result
    raise self._exception
  File "/usr/lib/python3.13/concurrent/futures/thread.py", line 59, in run
    result = self.fn(*self.args, **self.kwargs)
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/io/pyarrow.py", line 1662, in batches_for_task
    return list(self._record_batches_from_scan_tasks_and_deletes([task], deletes_per_file))
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/io/pyarrow.py", line 1699, in _record_batches_from_scan_tasks_and_deletes
    for batch in batches:
                 ^^^^^^^
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/io/pyarrow.py", line 1513, in _task_to_record_batches
    result_batch = _to_requested_schema(
        projected_schema,
    ...<2 lines>...
        downcast_ns_timestamp_to_us=True,
    )
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/io/pyarrow.py", line 1717, in _to_requested_schema
    struct_array = visit_with_partner(
        requested_schema,
    ...<2 lines>...
        ArrowAccessor(file_schema),
    )
  File "/usr/lib/python3.13/functools.py", line 934, in wrapper
    return dispatch(args[0].__class__)(*args, **kw)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/schema.py", line 662, in _
    return visitor.schema(schema, partner, visit_with_partner(schema.as_struct(), struct_partner, visitor, accessor))  # type: ignore
                                           ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/functools.py", line 934, in wrapper
    return dispatch(args[0].__class__)(*args, **kw)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/schema.py", line 677, in _
    return visitor.struct(struct, partner, field_results)
           ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/io/pyarrow.py", line 1816, in struct
    array = self._cast_if_needed(field, field_array)
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/io/pyarrow.py", line 1757, in _cast_if_needed
    promote(file_field.field_type, field.field_type), include_field_ids=self._include_field_ids
    ~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/functools.py", line 934, in wrapper
    return dispatch(args[0].__class__)(*args, **kw)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "playground/virtual-env/lib/python3.13/site-packages/pyiceberg/schema.py", line 1618, in promote
    raise ResolveError(f"Cannot promote {file_type} to {read_type}")
pyiceberg.exceptions.ResolveError: Cannot promote timestamptz to timestamptz_ns

Actual parquet:

./clickhouse client -q "SELECT * FROM file('2025-07-24T00-00-00_2025-07-25T00-00-00_01K11MWTJ1RX6Q7VRZP7YSN490.parquet', Parquet) order by (event_time, insertion_no) LIMIT 3;" --port 9002

2025-07-24 00:00:00.006136643   8298661145      2025-07-24 00:00:00.003000000   8129311262230   1       3627.72 1.88    false   0       0
2025-07-24 00:00:00.006136643   8298661146      2025-07-24 00:00:00.003000000   8129311262230   1       3627.77 1.409   false   0       0
2025-07-24 00:00:00.006136643   8298661147      2025-07-24 00:00:00.003000000   8129311262230   1       3627.95 4.17    false   0       0
```

### Willingness to contribute

- [ ] I can contribute a fix for this bug independently
- [ ] I would be willing to contribute a fix for this bug with guidance from the Iceberg community
- [ ] I cannot contribute a fix for this bug at this time

[kevinjqliu]

closing this, resolved by apache/iceberg-python#2294
this is also a duplicate of apache/iceberg-python#1045