Writing really long strings from pyarrow causes exception in fastparquet read.
```
Traceback (most recent call last):
File "/Users/twalker/repos/cloud-atlas/diag/right.py", line 47, in <module>
read_fastparquet()
File "/Users/twalker/repos/cloud-atlas/diag/right.py", line 41, in
read_fastparquet
dff = pf.to_pandas(['A'])
File
"/Users/twalker/anaconda/lib/python2.7/site-packages/fastparquet/api.py", line
426, in to_pandas
index=index, assign=parts)
File
"/Users/twalker/anaconda/lib/python2.7/site-packages/fastparquet/api.py", line
258, in read_row_group
scheme=self.file_scheme)
File
"/Users/twalker/anaconda/lib/python2.7/site-packages/fastparquet/core.py", line
344, in read_row_group
cats, selfmade, assign=assign)
File
"/Users/twalker/anaconda/lib/python2.7/site-packages/fastparquet/core.py", line
321, in read_row_group_arrays
catdef=out.get(name+'-catdef', None))
File
"/Users/twalker/anaconda/lib/python2.7/site-packages/fastparquet/core.py", line
235, in read_col
skip_nulls, selfmade=selfmade)
File
"/Users/twalker/anaconda/lib/python2.7/site-packages/fastparquet/core.py", line
99, in read_data_page
raw_bytes = _read_page(f, header, metadata)
File
"/Users/twalker/anaconda/lib/python2.7/site-packages/fastparquet/core.py", line
31, in _read_page
page_header.uncompressed_page_size)
AssertionError: found 175532 raw bytes (expected 200026)
```
If written with compression, it reports compression errors instead:
SNAPPY: `snappy.UncompressError: Error while decompressing: invalid input`
GZIP: `zlib.error: Error -3 while decompressing data: incorrect header check`
Minimal code to reproduce:
```
import os
import pandas as pd
import pyarrow
import pyarrow.parquet as arrow_pq
from fastparquet import ParquetFile
# data to generate
ROW_LENGTH = 40000 # decreasing below 32750ish eliminates exception
N_ROWS = 10
# file write params
ROW_GROUP_SIZE = 5 # Lower numbers eliminate exception, but strange data is
read (e.g. Nones)
FILENAME = 'test.parquet'
def write_arrow():
df = pd.DataFrame({'A': ['A'*ROW_LENGTH for _ in range(N_ROWS)]})
if os.path.isfile(FILENAME):
os.remove(FILENAME)
arrow_table = pyarrow.Table.from_pandas(df)
arrow_pq.write_table(arrow_table,
FILENAME,
use_dictionary=False,
compression='NONE',
row_group_size=ROW_GROUP_SIZE)
def read_arrow():
print "arrow:"
table2 = arrow_pq.read_table(FILENAME)
print table2.to_pandas().head()
def read_fastparquet():
print "fastparquet:"
pf = ParquetFile(FILENAME)
dff = pf.to_pandas(['A'])
print dff.head()
write_arrow()
read_arrow()
read_fastparquet()
```
Versions:
`fastparquet==0.1.6`
`pyarrow==0.10.0`
`pandas==0.22.0`
`sys.version '2.7.15 |Anaconda custom (64-bit)| (default, May 1 2018,
18:37:05) \n[GCC 4.2.1 Compatible Clang 4.0.1 (tags/RELEASE_401/final)]'`
Also opened issue here: https://github.com/dask/fastparquet/issues/375
[ Full content available at: https://github.com/apache/arrow/issues/2562 ]
This message was relayed via gitbox.apache.org for [email protected]
