[Fixed] Valueerror Unsupported Pickle Protocol 5

Users who are working on the pickle library in Python may come across this error. This article explains how you can get rid of this error.

What is the pickle protocol?

If you wish to serialize and deserialize Python objects, the pickle library should be your go-to library. You can change your object in the form of byte streams with the help of serializing and vice versa with the option of deserializing. You can perform the following operations on these byte stream objects:

• Saving and loading to the disk
• Passing over network
• Caching
• Storing on your database

Reasons of valueerror unsupported pickle protocol 5 Error

• Incompatible versions
• Abrupt updation of the Python version
• Varying versions of Python on nodes in the Distributed systems

Resolving valueerror unsupported pickle protocol 5 error

The following methods will help you in resolving the ‘valueerror unsupported pickle protocol 5’ error.

Checking compatibility

There might be a difference between the protocol version your Python environment supports and the protocol version you have specified to serialize the objects.

Upgrading Python version

You need to update the Python version to 3.8 or higher so that it supports pickle protocol 5. You can check the version of Python with the given command:

python --version

Specifying protocol version

You can specify protocol 5 while writing the necessary pickling command. The command given below will help you manually set the protocol version to 5 if your Python version is 3.8 or higher.

pickle.dump(obj, file, protocol=5)

Downgrading protocol version

At times, you might require downgrading the protocol version. Think of a situation when you have pickled the object in a higher Python version, but you plan to unpickle in some other lower version of Python. In this case, the higher version protocol can’t match with the lower version one. So, it should automatically downgrade in order to match the lower version of Python to carry out the unpickling process.

Check this code to interpret the automated downgrading of protocol:

pickle.load(file, fix_imports=True, encoding='latin1')

Resolving in pandas

If you get this error in pandas, there are two ways to resolve this: either using pickle5 or protocol method. You can change it to a lower version. The first example uses the pickle5 library.

import pickle5
import pandas as pd

with open('pickle_file.pkl', 'rb') as f:
    df = pickle5.load(f)

# Convert the DataFrame to pickle protocol 4
df.to_pickle('pickle_file_v4.pkl', protocol=4)

The second example uses the protocol parameter.

import pickle
import pandas as pd

with open('pickle_file.pkl', 'rb') as f:
    df = pd.read_pickle(f)

# Convert the DataFrame to pickle protocol 4
df.to_pickle('pickle_file_v4.pkl', protocol=4)

Choosing the right protocol version

The choice of the correct pickle protocol is extremely important. The pickle protocol version depends on the Python version you are using. Basically, one needs to see which Python version the object will be unpickled in. So you need to keep the following things in mind:

• For Python 2 and below users, use the protocol 2.
• Use protocol 3 for Python 3.0 or newer.
• Use protocol 4 for Python 3.4 or newer.
• Use protocol 5 for Python 3.8 or newer.

As you go higher, it supports more features but has lesser compatibility.

Using pickle5 mode

You can install the pickle5 library as an alternative. It performs the same functions as the pickle library. If anyone is working on Google Colab or using a Jupyter Notebook, then the third command works for installation.

pip install pickle5
pip3 install pickle5
!pip3 install pickle5

This library can be considered as an alternative for Python 3.5, 3.5, and 3.7 users. Once you have installed the pickle5 library, you can import it as a pickle object so the rest of the code will remain the same.

import pickle5 as pickle

valueerror unsupported pickle protocol 5 airflow

If this error occurs in airflow, it is primarily because of incompatible versions of airflow and Python. Check that your airflow version matches the worker version. Protocol 4 of pickle is the safest protocol to go with. If you don’t require security improvements or features of protocol 5, you can keep using protocol 4.

For Python 3.8+ users, protocol 5 works the best with airflow. Users who are migrating from a recent version to a previous version can work with a lower Pickle protocol.

Otherwise, go with the pickle5 module installation. This is the best alternative.

valueerror unsupported pickle protocol 5 joblib

In joblib, valueerror unsupported pickle protocol 5 error occurs when you serialize your object with Pickle Protocol 5. However, the current environment doesn’t support this version. Use joblib.load(filename, protocol=n) command to force joblib to use a particular protocol. This is similar to explicitly specifying the Pickle protocol version. You should also update the Python version to 3.8. This will make it suitable for Pickle Protocol 5. The simplest solution includes the installation of the pickle5 module.

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Other Tips while working with pickle protocols

In order to get rid of the ‘valueerror unsupported pickle protocol 5’ error, you can check out some tips:

• Use the highest pickle protocol if possible.
• Check your Python version first.
• With pickle5, you don’t need to think of compatibility problems.
• For pickle protocol 5, make sure that you are using Pandas 1.4.0 or later version.

FAQS

Conclusion

This article explains how users can resolve the ‘valueerror unsupported pickle protocol 5’ error while using the pickle module of Python. It also lists some tips that users can find useful while working with the pickle library.