lukaswenzl-akur8 opened a new issue, #44048:
URL: https://github.com/apache/arrow/issues/44048
### Describe the bug, including details regarding any error messages,
version, and platform.
Converting from pandas to pyarrow with Table.from_pandas for dataframes with
categorical columns with large dictionaries fails. Similarly loading such a
column from a parquet file and converting to pandas with Table.to_pandas()
fails.
The failure happens when the total number of characters reaches the size of
an unsigned 32bit integer (`np.sum(df["float_gran"].cat.categories.str.len()) >
2_147_483_647`), indicating it may be an int32 Overflow issue.
Below an example code that reproduces the failure
```python
>>> import pyarrow as pa
>>> import pyarrow.parquet as pq
>>> import pandas as pd
>>>pd.__version__
'2.2.2'
>>> import numpy as np
>>> pa.__version__
'17.0.0'
>>>n_rows = 120_000_000
>>>df = pd.DataFrame()
>>>df["float_gran"] = np.random.rand(n_rows)
>>>df["float_gran"] = df["float_gran"].astype(str).astype("category")
>>>pa.Table.from_pandas(df)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
Cell In[6], line 1
----> 1 pa.Table.from_pandas(df)
File
~/miniforge3/envs/localtesting/lib/python3.9/site-packages/pyarrow/table.pxi:4623,
in pyarrow.lib.Table.from_pandas()
File
~/miniforge3/envs/localtesting/lib/python3.9/site-packages/pyarrow/pandas_compat.py:616,
in dataframe_to_arrays(df, schema, preserve_index, nthreads, columns, safe)
611 return (isinstance(arr, np.ndarray) and
612 arr.flags.contiguous and
613 issubclass(arr.dtype.type, np.integer))
615 if nthreads == 1:
--> 616 arrays = [convert_column(c, f)
617 for c, f in zip(columns_to_convert, convert_fields)]
618 else:
619 arrays = []
File
~/miniforge3/envs/localtesting/lib/python3.9/site-packages/pyarrow/pandas_compat.py:616,
in <listcomp>(.0)
611 return (isinstance(arr, np.ndarray) and
612 arr.flags.contiguous and
613 issubclass(arr.dtype.type, np.integer))
615 if nthreads == 1:
--> 616 arrays = [convert_column(c, f)
617 for c, f in zip(columns_to_convert, convert_fields)]
618 else:
619 arrays = []
File
~/miniforge3/envs/localtesting/lib/python3.9/site-packages/pyarrow/pandas_compat.py:597,
in dataframe_to_arrays.<locals>.convert_column(col, field)
594 type_ = field.type
596 try:
--> 597 result = pa.array(col, type=type_, from_pandas=True, safe=safe)
598 except (pa.ArrowInvalid,
599 pa.ArrowNotImplementedError,
600 pa.ArrowTypeError) as e:
601 e.args += ("Conversion failed for column {!s} with type {!s}"
602 .format(col.name, col.dtype),)
File
~/miniforge3/envs/localtesting/lib/python3.9/site-packages/pyarrow/array.pxi:346,
in pyarrow.lib.array()
File
~/miniforge3/envs/localtesting/lib/python3.9/site-packages/pyarrow/array.pxi:3863,
in pyarrow.lib.DictionaryArray.from_arrays()
TypeError: Cannot convert pyarrow.lib.ChunkedArray to pyarrow.lib.Array
```
Note: the same error message was noted in [issue
#41936](https://github.com/apache/arrow/issues/41936), but there the discussion
was about RecordBatch and it was noted Table.from_pandas, used here, should
work fine.
```python
>>>from pyarrow.interchange import from_dataframe
>>>table = from_dataframe(df)
>>>table
pyarrow.Table
float_gran: dictionary<values=large_string, indices=int32, ordered=0>
----
float_gran: [ -- dictionary:
["0.00010000625394479545","0.00010000637024687453","0.00010002156605048995","0.00010002375983830802","0.00010003348618559116",...,"9.996332028860966e-05","9.996352231378403e-05","9.996744926299428e-06","9.99769273748452e-05","9.99829165827526e-05"]
-- indices:
[72271820,16482433,4156153,49996213,77690435,...,24623248,57247299,27016212,102115156,112204811]]
>>>table.to_pandas()
>>>#works!
>>>pq.write_table(table, "test", use_dictionary=False)
>>>table_loaded = pq.read_table("test")
>>>table_loaded.to_pandas()
---------------------------------------------------------------------------
ArrowCapacityError Traceback (most recent call last)
Cell In[18], line 1
----> 1 table_loaded.to_pandas()
File
~/miniforge3/envs/localtesting/lib/python3.9/site-packages/pyarrow/array.pxi:885,
in pyarrow.lib._PandasConvertible.to_pandas()
File
~/miniforge3/envs/localtesting/lib/python3.9/site-packages/pyarrow/table.pxi:5002,
in pyarrow.lib.Table._to_pandas()
File
~/miniforge3/envs/localtesting/lib/python3.9/site-packages/pyarrow/pandas_compat.py:784,
in table_to_dataframe(options, table, categories, ignore_metadata,
types_mapper)
781 columns = _deserialize_column_index(table, all_columns,
column_indexes)
783 column_names = table.column_names
--> 784 result = pa.lib.table_to_blocks(options, table, categories,
785 list(ext_columns_dtypes.keys()))
786 if _pandas_api.is_ge_v3():
787 from pandas.api.internals import create_dataframe_from_blocks
File
~/miniforge3/envs/localtesting/lib/python3.9/site-packages/pyarrow/table.pxi:3941,
in pyarrow.lib.table_to_blocks()
File
~/miniforge3/envs/localtesting/lib/python3.9/site-packages/pyarrow/error.pxi:92,
in pyarrow.lib.check_status()
ArrowCapacityError: array cannot contain more than 2147483646 bytes, have
2147483657
```
Tested on macos Sonoma 14.5, errors also happened on linux servers
It seems from_dataframe avoids the error by leveraging a 'large_string'
datatype. However we find the from_dataframe method to perform significantly
worse than from_pandas in most cases and would therefore like to avoid using
it. Additionally the large_string datatype seems to be lost on reload.
Is there already a way to reliably avoid the TypeError and
ArrowCapacityError in the optimized methods for pandas and is this a bug that
could be fixed in future versions?
### Component(s)
Python
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