[jira] [Created] (ARROW-10056) PyArrow writes invalid Feather v2 file: OSError: Verification of flatbuffer-encoded Footer failed.

["Gert Hulselmans (Jira)" <ji...@apache.org>]

Gert Hulselmans created ARROW-10056:
---------------------------------------

             Summary: PyArrow writes invalid Feather v2 file: OSError: Verification of flatbuffer-encoded Footer failed.
                 Key: ARROW-10056
                 URL: https://issues.apache.org/jira/browse/ARROW-10056
             Project: Apache Arrow
          Issue Type: Bug
          Components: Python
    Affects Versions: 1.0.1
         Environment: CentOS7
conda environment with pyarrow 1.0.1, numpy 1.19.1 and pandas 1.1.1

            Reporter: Gert Hulselmans


pyarrow writes an invalid Feather v2 file, which it can't read afterwards.


{code:java}
    OSError: Verification of flatbuffer-encoded Footer failed.
{code}


The following code reproduces the problem for me:

{code:python}
import pyarrow as pa
import numpy as np
import pandas as pd

nbr_regions = 1223024
nbr_motifs = 4891

# Create (big) dataframe.
df = pd.DataFrame(
    np.arange(nbr_regions * nbr_motifs, dtype=np.float32).reshape((nbr_regions, nbr_motifs)),
    index=pd.Index(['region' + str(i) for i in range(nbr_regions)], name='regions'),
    columns=pd.Index(['motif' + str(i) for i in range(nbr_motifs)], name='motifs')
)

# Transpose dataframe
df_transposed = df.transpose()

# Write transposed dataframe to Feather v2 format.
pf.write_feather(df_transposed, 'df_transposed.feather')

# Trying to read the transposed dataframe from Feather v2 format, results in this error:
df_transposed_read = pf.read_feather('df_transposed.feather')
{code}

{code:python}
---------------------------------------------------------------------------
OSError                                   Traceback (most recent call last)
<ipython-input-64-b41ad5157e77> in <module>
----> 1 df_transposed_read = pf.read_feather('df_transposed.feather')

/software/miniconda3/envs/pyarrow/lib/python3.8/site-packages/pyarrow/feather.py in read_feather(source, columns, use_threads, memory_map)
    213     """
    214     _check_pandas_version()
--> 215     return (read_table(source, columns=columns, memory_map=memory_map)
    216             .to_pandas(use_threads=use_threads))
    217

/software/miniconda3/envs/pyarrow/lib/python3.8/site-packages/pyarrow/feather.py in read_table(source, columns, memory_map)
    235     """
    236     reader = ext.FeatherReader()
--> 237     reader.open(source, use_memory_map=memory_map)
    238
    239     if columns is None:

/software/miniconda3/envs/pyarrow/lib/python3.8/site-packages/pyarrow/feather.pxi in pyarrow.lib.FeatherReader.open()

/software/miniconda3/envs/pyarrow/lib/python3.8/site-packages/pyarrow/error.pxi in pyarrow.lib.pyarrow_internal_check_status()

/software/miniconda3/envs/pyarrow/lib/python3.8/site-packages/pyarrow/error.pxi in pyarrow.lib.check_status()

OSError: Verification of flatbuffer-encoded Footer failed.
{code}

Later I discovered that it happens also if the original dataframe is created in the transposed order:
{code:python}
# Create (big) dataframe.
df_without_transpose = pd.DataFrame(
    np.arange(nbr_motifs * nbr_regions, dtype=np.float32).reshape((nbr_motifs, nbr_regions)),
    index=pd.Index(['motif' + str(i) for i in range(nbr_motifs)], name='motifs'),
    columns=pd.Index(['region' + str(i) for i in range(nbr_regions)], name='regions'),
)

pf.write_feather(df_without_transpose, 'df_without_transpose.feather')

df_without_transpose_read = pf.read_feather('df_without_transpose.feather')
---------------------------------------------------------------------------
OSError                                   Traceback (most recent call last)
<ipython-input-91-3cdad1d58c35> in <module>
----> 1 df_without_transpose_read = pf.read_feather('df_without_transpose.feather')

/software/miniconda3/envs/pyarrow/lib/python3.8/site-packages/pyarrow/feather.py in read_feather(source, columns, use_threads, memory_map)
    213     """
    214     _check_pandas_version()
--> 215     return (read_table(source, columns=columns, memory_map=memory_map)
    216             .to_pandas(use_threads=use_threads))
    217


/software/miniconda3/envs/pyarrow/lib/python3.8/site-packages/pyarrow/feather.py in read_table(source, columns, memory_map)
    235     """
    236     reader = ext.FeatherReader()
--> 237     reader.open(source, use_memory_map=memory_map)
    238
    239     if columns is None:


/software/miniconda3/envs/pyarrow/lib/python3.8/site-packages/pyarrow/feather.pxi in pyarrow.lib.FeatherReader.open()


/software/miniconda3/envs/pyarrow/lib/python3.8/site-packages/pyarrow/error.pxi in pyarrow.lib.pyarrow_internal_check_status()


/software/miniconda3/envs/pyarrow/lib/python3.8/site-packages/pyarrow/error.pxi in pyarrow.lib.check_status()

OSError: Verification of flatbuffer-encoded Footer failed.
{code}

Writing to Feather v1 format works:
{code:python}
pf.write_feather(df_transposed, 'df_transposed.v1.feather', version=1)

df_transposed_read_v1 = pf.read_feather('df_transposed.v1.feather')

# Now do the same, but also save the index in the Feather v1 file.
df_transposed_reset_index = df_transposed.reset_index()

pf.write_feather(df_transposed_reset_index, 'df_transposed_reset_index.v1.feather', version=1)

df_transposed_reset_index_read_v1 = pf.read_feather('df_transposed_reset_index.v1.feather')

# Returns True
df_transposed_reset_index_read_v1.equals(df_transposed)
{code}





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