[ARROW-1996] [Python] pyarrow.read_serialized cannot read concatenated records

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.8.0
• Fix Version/s: 0.11.0
• Component/s: Python
• Labels: pull-request-available
• Environment: Linux
• Assignee: Wes McKinney
• Reporter: Richard Shin
• Created: 15/Jan/18 08:58
• Updated: 25/Sep/18 08:26
• Resolved: 25/Sep/18 08:18

Description

The following code

import pyarrow as pa

f = pa.OSFile('arrow_test', 'w')
pa.serialize_to(12, f)
pa.serialize_to(23, f)
f.close()

f = pa.OSFile('arrow_test', 'r')
print(pa.read_serialized(f).deserialize())
print(pa.read_serialized(f).deserialize())
f.close()

gives the following result:

$ python pyarrow_test.py
First: 12
Traceback (most recent call last):
File "pyarrow_test.py", line 10, in <module>
print('Second: {}'.format(pa.read_serialized(f).deserialize()))
File "pyarrow/serialization.pxi", line 347, in pyarrow.lib.read_serialized (/arrow/python/build/temp.linux-x86_64-2.7/lib.cxx:79159)
File "pyarrow/error.pxi", line 77, in pyarrow.lib.check_status (/arrow/python/build/temp.linux-x86_64-2.7/lib.cxx:8270)
pyarrow.lib.ArrowInvalid: Expected schema message in stream, was null or length 0

I would have expected read_serialized to sucessfully read the second value.

Issue Links

• links to: GitHub Pull Request #1667