[ARROW-17893] [Python] Bug: Wrong reading of timedelta

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 8.0.0
• Fix Version/s: 11.0.0
• Component/s: Python
• Labels: pull-request-available
• Environment: macOS 12.6 on an Apple M1 Ultra
• External issue URL: https://github.com/apache/arrow/issues/20438
• Assignee: Alenka Frim
• Reporter: Yaser Alraddadi
• Created: 29/Sep/22 13:04
• Updated: 11/Jan/23 11:56
• Resolved: 09/Nov/22 16:26

Description

When there is a timedelta and a list of dictionary that also has timedelta as well, reading the upper timedelta in feather format sometimes gives wrong reading.

below is an example if you check the printed results sometime it reads the upper timedelta as 0 days 03:40:23 correct, and sometimes as 153 days 01:03:20 wrong

Here is the code, also it is attached as check_timedelta.py

 

from datetime import datetime, timedelta
import pandas as pd
import pyarrow.feather as feather
time_1 = datetime.fromisoformat("2022-04-21T10:18:12+03:00")
time_2 = datetime.fromisoformat("2022-04-21T13:58:35+03:00")
data = [
    {
        "waiting_time": timedelta(seconds=12, microseconds=1),
    },
    {
        "waiting_time": timedelta(seconds=1020),
    },
    {
        "waiting_time": timedelta(seconds=960),
    },
    {
        "waiting_time": timedelta(seconds=960),
    },
    {
        "waiting_time": timedelta(seconds=960),
    },
    {
        "waiting_time": timedelta(seconds=815, microseconds=1),
    },
]
df = pd.DataFrame(
    [
        {
            "time_1": time_1,
            "time_2": time_2,
            "data": data,
            "timedelta_1": time_2 - time_1,
            "timedelta_2": timedelta(hours=3, minutes=40, seconds=23),
        },
    ]
)

print("Correct timedelta_1: ", df["timedelta_1"].item())
print("Correct timedelta_2: ", df["timedelta_2"].item())

with open(f"records.feather.lz4", "wb") as f:
    feather.write_feather(df, f, compression="lz4")

for _ in range(10):
    with open(f"records.feather.lz4", "rb") as f:
        print("Reading timedelta_1: ", feather.read_feather(f)["timedelta_1"].item())
        print("Reading timedelta_2: ", feather.read_feather(f)["timedelta_2"].item())

 

 

Printed Results

 

Correct timedelta_1:  0 days 03:40:23
Correct timedelta_2:  0 days 03:40:23
Reading timedelta_1:  0 days 03:40:23
Reading timedelta_2:  0 days 03:40:23
Reading timedelta_1:  0 days 03:40:23
Reading timedelta_2:  0 days 03:40:23
Reading timedelta_1:  153 days 01:03:20
Reading timedelta_2:  153 days 01:03:20
Reading timedelta_1:  0 days 03:40:23
Reading timedelta_2:  0 days 03:40:23
Reading timedelta_1:  0 days 03:40:23
Reading timedelta_2:  0 days 03:40:23
Reading timedelta_1:  0 days 03:40:23
Reading timedelta_2:  153 days 01:03:20
Reading timedelta_1:  153 days 01:03:20
Reading timedelta_2:  0 days 03:40:23
Reading timedelta_1:  0 days 03:40:23
Reading timedelta_2:  153 days 01:03:20
Reading timedelta_1:  153 days 01:03:20
Reading timedelta_2:  153 days 01:03:20
Reading timedelta_1:  153 days 01:03:20
Reading timedelta_2:  153 days 01:03:20

 

 

Issue Links

• links to: GitHub Pull Request #14531