David Li created ARROW-10480:
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Summary: [Python] Parquet write_table creates gzipped Parquet
file, not Parquet with gzip compression
Key: ARROW-10480
URL: https://issues.apache.org/jira/browse/ARROW-10480
Project: Apache Arrow
Issue Type: Bug
Components: Python
Affects Versions: 2.0.0
Reporter: David Li
Fix For: 2.0.1
Writing "foo.parquet.gz" in Arrow 2.0.0 creates a gzipped Parquet file, which
Arrow can't read back, while in 1.0.1 it created a Parquet file with gzip
compression. Hence I think this is a regression.
In Arrow 2.0.0:
{noformat}
> pip freeze
numpy==1.19.4
pyarrow==2.0.0
> python write.py
Arrow: 2.0.0
Read/write with PyArrow:
test.pyarrow.gz: gzip compressed data, from Unix, original size modulo 2^32 630
Traceback (most recent call last):
File "write.py", line 12, in <module>
print(pq.read_table("test.pyarrow.gz"))
File
"/home/lidavidm/Code/twosigma/arrow-regression/venv/lib/python3.8/site-packages/pyarrow/parquet.py",
line 1607, in read_table
dataset = _ParquetDatasetV2(
File
"/home/lidavidm/Code/twosigma/arrow-regression/venv/lib/python3.8/site-packages/pyarrow/parquet.py",
line 1452, in __init__
[fragment], schema=fragment.physical_schema,
File "pyarrow/_dataset.pyx", line 761, in
pyarrow._dataset.Fragment.physical_schema.__get__
File "pyarrow/error.pxi", line 122, in
pyarrow.lib.pyarrow_internal_check_status
File "pyarrow/error.pxi", line 99, in pyarrow.lib.check_status
OSError: Could not open parquet input source 'test.pyarrow.gz': Invalid:
Parquet magic bytes not found in footer. Either the file is corrupted or this
is not a parquet file. {noformat}
But in Arrow 1.0.1:
{noformat}
> pip freeze
numpy==1.19.4
pyarrow==1.0.1
> python write.py
Arrow: 1.0.1
Read/write with PyArrow:
test.pyarrow.gz: Apache Parquet
pyarrow.Table
ints: int64 {noformat}
Reproduction:
{code:python}
import pyarrow as pa
import pyarrow.parquet as pq
import subprocess
print("Arrow:", pa.__version__)
print()
print("Read/write with PyArrow:")
table = pa.table([pa.array(range(4))], names=["ints"])
pq.write_table(table, "test.pyarrow.gz", compression="GZIP")
subprocess.check_call(["file", "test.pyarrow.gz"])
print(pq.read_table("test.pyarrow.gz"))
{code}
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