Overflow encountered in long_scalars

[smcolby]

When using pandas' to_hdf method with tables flag (to signal use of pytables) on Windows (no issue with Linux or Mac), the following warning is presented:

tables\leaf.py:318: RuntimeWarning: overflow encountered in long_scalars
  expected_mb = (expectedrows * rowsize) // MB

However, after reading the resulting file back into memory, the two data frames are identical in content.

This issue was raised on pandas' repository, but they closed indicating it should be addressed here.

[avalentino]

Dear @smcolby
thanks for reporting.
It would be nice to have a small and self-contained example to reproduce the issue

[smcolby]

Apologies for the delay! The below will produce the error on Windows.

import numpy as np
import pandas as pd

pd.DataFrame(np.empty((100000000, 7))).to_hdf('test.h5', 'test', format='table', complib='blosc', complevel=5)