BUG: Load ORC-format data failed when pandas version>1.2.0.dev0

[amznero]

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• (optional) I have confirmed this bug exists on the master branch of pandas.
  https://github.com/pandas-dev/pandas/blob/master/pandas/io/orc.py#L15-L54

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Code Sample, a copy-pastable example

...
import pandas as pd
orc_data = pd.read_orc(orc_file_path)

Problem description

Pandas uses PyArrow package to load ORC/Parquet data.

For the orc data format, it will use pyarrow.orc.ORCFile to read data (orc.py), but the PyArrow does not declare orc in __init__.py file, so pandas will raise an AttributeError: module 'pyarrow' has no attribute 'orc'

This bug will occur if the Pandas version is greater than v1.2.0.dev0(after commit-6d1541e). Before that, pandas/io/orc.py will declare import pyarrow.orc before uses pyarrow to load orc data(v1.1.5/pandas/io.orc.py/).

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Testing environment:

• Ubuntu 18.04
• python 3.7
• pandas v1.2.1
• pyarrow v3.0.0 (install via pip)(I haven't installed pyarrow via Conda for testing yet.)

[lithomas1]

pyarrow.orc doesn't seem to work in general for pyarrow > 0.15.0 I think. On pip, I get

>>> import pyarrow.orc
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\liwende\Anaconda3\lib\site-packages\pyarrow\orc.py", line 24, in <module>
    import pyarrow._orc as _orc
ModuleNotFoundError: No module named 'pyarrow._orc'

and with conda I get

>>> import pyarrow.orc
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\liwende\Anaconda3\lib\site-packages\pyarrow\__init__.py", line 54, in <module>
    from pyarrow.lib import cpu_count, set_cpu_count
ImportError: DLL load failed: The specified procedure could not be found.

(both with pyarrow 3.0.0)
Maybe related? https://issues.apache.org/jira/browse/ARROW-7811

Other than that, agreed that it's a bug.

[amznero]

Seems this problem(pyarrow.orc) is related to the operating system

I can run it successfully on Linux(Ubuntu), but I have the same problem as you mentioned on Windows10.

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Maybe related to https://stackoverflow.com/a/58967391