Python psycopg2 install error

Psycopg is a PostgreSQL adapter for the Python programming language. It is a wrapper for the libpq, the official PostgreSQL client library.

Psycopg is a PostgreSQL adapter for the Python programming language. It is a
wrapper for the libpq, the official PostgreSQL client library.

Quick Install¶

For most operating systems, the quickest way to install Psycopg is using the
wheel package available on PyPI:

$ pip install psycopg2-binary

This will install a pre-compiled binary version of the module which does not
require the build or runtime prerequisites described below. Make sure to use
an up-to-date version of pip (you can upgrade it using something
like pip install -U pip).

You may then import the psycopg2 package, as usual:

import psycopg2

# Connect to your postgres DB
conn = psycopg2.connect("dbname=test user=postgres")

# Open a cursor to perform database operations
cur = conn.cursor()

# Execute a query
cur.execute("SELECT * FROM my_data")

# Retrieve query results
records = cur.fetchall()

psycopg vs psycopg-binary¶

The psycopg2-binary package is meant for beginners to start playing
with Python and PostgreSQL without the need to meet the build
requirements.

If you are the maintainer of a published package depending on psycopg2
you shouldn’t use psycopg2-binary as a module dependency. For
production use you are advised to use the source distribution.

The binary packages come with their own versions of a few C libraries,
among which libpq and libssl, which will be used regardless of other
libraries available on the client: upgrading the system libraries will not
upgrade the libraries used by psycopg2. Please build psycopg2 from
source if you want to maintain binary upgradeability.

Warning

The psycopg2 wheel package comes packaged, among the others, with its
own libssl binary. This may create conflicts with other extension
modules binding with libssl as well, for instance with the Python
ssl module: in some cases, under concurrency, the interaction between
the two libraries may result in a segfault. In case of doubts you are
advised to use a package built from source.

Change in binary packages between Psycopg 2.7 and 2.8¶

In version 2.7.x, pip install psycopg2 would have tried to install
automatically the binary package of Psycopg. Because of concurrency problems
binary packages have displayed, psycopg2-binary has become a separate
package, and from 2.8 it has become the only way to install the binary
package.

If you are using Psycopg 2.7 and you want to disable the use of wheel binary
packages, relying on the system libraries available on your client, you
can use the pip --no-binary option, e.g.:

$ pip install --no-binary :all: psycopg2

which can be specified in your requirements.txt files too, e.g. use:

psycopg2>=2.7,<2.8 --no-binary psycopg2

to use the last bugfix release of the psycopg2 2.7 package, specifying to
always compile it from source. Of course in this case you will have to meet
the build prerequisites.

Prerequisites¶

The current psycopg2 implementation supports:

  • Python versions from 3.6 to 3.11

  • PostgreSQL server versions from 7.4 to 15

  • PostgreSQL client library version from 9.1

Note

Not all the psycopg2 versions support all the supported Python versions.

Please see the release notes to verify when the support for
a new Python version was added and when the support for an old Python
version was removed.

Build prerequisites¶

The build prerequisites are to be met in order to install Psycopg from source
code, from a source distribution package, GitHub or from PyPI.

Psycopg is a C wrapper around the libpq PostgreSQL client library. To install
it from sources you will need:

  • A C compiler.

  • The Python header files. They are usually installed in a package such as
    python-dev or python3-dev. A message such as error: Python.h: No
    such file or directory
    is an indication that the Python headers are
    missing.

  • The libpq header files. They are usually installed in a package such as
    libpq-dev. If you get an error: libpq-fe.h: No such file or directory
    you are missing them.

  • The pg_config program: it is usually installed by the
    libpq-dev package but sometimes it is not in a PATH directory.
    Having it in the PATH greatly streamlines the installation, so try
    running pg_config --version: if it returns an error or an unexpected
    version number then locate the directory containing the pg_config
    shipped with the right libpq version (usually
    /usr/lib/postgresql/X.Y/bin/) and add it to the PATH:

    $ export PATH=/usr/lib/postgresql/X.Y/bin/:$PATH
    

    You only need pg_config to compile psycopg2, not for its
    regular usage.

Once everything is in place it’s just a matter of running the standard:

or, from the directory containing the source code:

$ python setup.py build
$ python setup.py install

Runtime requirements¶

Unless you compile psycopg2 as a static library, or you install it from a
self-contained wheel package, it will need the libpq library at runtime
(usually distributed in a libpq.so or libpq.dll file). psycopg2
relies on the host OS to find the library if the library is installed in a
standard location there is usually no problem; if the library is in a
non-standard location you will have to tell Psycopg how to find it,
which is OS-dependent (for instance setting a suitable
LD_LIBRARY_PATH on Linux).

Note

The libpq header files used to compile psycopg2 should match the
version of the library linked at runtime. If you get errors about missing
or mismatching libraries when importing psycopg2 check (e.g. using
ldd) if the module psycopg2/_psycopg.so is linked to the
right libpq.so.

Note

Whatever version of libpq psycopg2 is compiled with, it will be
possible to connect to PostgreSQL servers of any supported version: just
install the most recent libpq version or the most practical, without
trying to match it to the version of the PostgreSQL server you will have
to connect to.

Non-standard builds¶

If you have less standard requirements such as:

  • creating a debug build,

  • using pg_config not in the PATH,

then take a look at the setup.cfg file.

Some of the options available in setup.cfg are also available as command
line arguments of the build_ext sub-command. For instance you can specify
an alternate pg_config location using:

$ python setup.py build_ext --pg-config /path/to/pg_config build

Use python setup.py build_ext --help to get a list of the options
supported.

Creating a debug build¶

In case of problems, Psycopg can be configured to emit detailed debug
messages, which can be very useful for diagnostics and to report a bug. In
order to create a debug package:

  • Download and unpack the Psycopg source package (the .tar.gz
    package).

  • Edit the setup.cfg file adding the PSYCOPG_DEBUG flag to the
    define option.

  • Compile and install the package.

  • Set the PSYCOPG_DEBUG environment variable:

  • Run your program (making sure that the psycopg2 package imported is the
    one you just compiled and not e.g. the system one): you will have a copious
    stream of informations printed on stderr.

Non-standard Python Implementation¶

The psycopg2 package is the current mature implementation of the adapter: it
is a C extension and as such it is only compatible with CPython. If you want
to use Psycopg on a different Python implementation (PyPy, Jython, IronPython)
there is a couple of alternative:

  • a Ctypes port, but it is not as mature as the C implementation yet
    and it is not as feature-complete;

  • a CFFI port which is currently more used and reported more efficient on
    PyPy, but please be careful of its version numbers because they are not
    aligned to the official psycopg2 ones and some features may differ.

Running the test suite¶

Once psycopg2 is installed you can run the test suite to verify it is
working correctly. From the source directory, you can run:

$ python -c "import tests; tests.unittest.main(defaultTest='tests.test_suite')" --verbose

The tests run against a database called psycopg2_test on UNIX socket and
the standard port. You can configure a different database to run the test by
setting the environment variables:

  • PSYCOPG2_TESTDB

  • PSYCOPG2_TESTDB_HOST

  • PSYCOPG2_TESTDB_PORT

  • PSYCOPG2_TESTDB_USER

The database should already exist before running the tests.

If you still have problems¶

Try the following. In order:

  • Read again the Build prerequisites.

  • Read the FAQ.

  • Google for psycopg2 your error message. Especially useful the week
    after the release of a new OS X version.

  • Write to the Mailing List.

  • If you think that you have discovered a bug, test failure or missing feature
    please raise a ticket in the bug tracker.

  • Complain on your blog or on Twitter that psycopg2 is the worst package
    ever and about the quality time you have wasted figuring out the correct
    ARCHFLAGS. Especially useful from the Starbucks near you.

Many developers face the issue of the No module named ‘psycopg2’ when they try to take their project to the production level. With the help of this article, we will understand the cause of the error and the possible solutions to avoid them. Let’s dive in.

What is ‘psycopg2’?

‘psycopg2’ is the most popular database adapter dealing in PostgreSQL. Its core is to completely implement the Python DB API 2.0 specification and the thread-safety. That means it can allow several threads to share a standard connection. It can easily handle concurrent insertion and deletion in an application. It can create or destroy lots of connections simultaneously.

Architechture behind ‘psycopg2’

‘psycopg2’ uses a libpq wrapper, which implements the C programming language interface. It consists of a set of library functions that allow client programs to receive the results of the queries passed to the PostgreSQL backend server.

Cause behind the error: No module named ‘psycopg2’

To execute the program smoothly, some pre-requisites should be met. Failing to meet these requirements will trigger import errors during the compilation.

Pre-requisites are :

  1. Python Version
    • 3.6 to 3.9
  2. PostgreSQL server versions
    • 7.4 to 13
  3. PostgreSQL client library version
    • from 9.1
  4. C compiler
  5. Package such as python-dev or python3-dev to install python header files.
  6. libpq-dev package containing libpq header files.
  7. pg-config file should be present in the PATH file. It compiles ‘psycopg2

If the system does not meet the above requirements, the ‘psycopg2’ module will not be installed, leading to no modules name ‘psycopg2’ error. This error is often viewed by programmers who don’t have a C compiler in their system. As the binaries fail to install, the module will not work.

Resolving the issue: No module named ‘psycopg2’

To resolve the issue, we must satisfy all the pre-requisites laid by the ‘psycopg2’ to meet its build requirements. However, pyscopg2 also provides us with a binary package with its versions of C libraries, libpq, and libssl, which will be used regardless of other libraries available to the client.

Perform these commands to resolve the issue:

pip uninstall psycopg2
pip install psycopg2-binary

Running the above commands will solve the problem, but the installation may fail in a few cases due to a non-supportive environment. Follow these steps to install the precompiled library –

  1. Go to the Precompiled Library Packages list.
  2. Then download the wheel file (.whl) for the psycopg module.
  3. Then use the command pip install <file>.whl to install the library using downloaded wheel file.

Using the above steps will guarantee installing psycopg2 on your computer.

Working On Incorrect Virtual Enviornment?

Many “No module named psycopg2” errors occur due to working on incorrect virtual environments and installing the ‘psycopg2’ on a different environment. Suppose you have two versions of python3 installed, and how will you install ‘psycopg2’ to a specific python?

Use the following command to call your python and install the package in your respective environment –

python3 -m pip install psycopg2

This will ensure that you install the psycopg2 module in the working environment. Hopefully, this resolves the issue. Moreover, if you face the C Compiler issues in this method, use the precompiled method as mentioned last way.

Recommended Reading | [Solved] No Module Named Numpy in Python

Resolving No module named ‘psycopg2’ in AWS EC2 lambda/ Linux OS

However, one cannot rely on binary packages if they are using them in production, and we should build the ‘psycopg2’ from the source. Because upgrading the system libraries will not upgrade the libraries used by ‘psycopg2'. Hence, there might be a dependencies error.

One can perform these commands to solve the problem

sudo apt install gcc g++ build-essential
sudo apt install python3-dev
sudo apt install libpq-dev
python -m pip install psycopg2

How to solve the No module named ‘psycopg2’ Error in Conda/Anaconda?

Conda or Anaconda has its virtual environment. So to work ‘psycopg2’, you have to install psycopg2 on Conda Environment. Use conda install psycopg2 to install psycopg2.

How to solve the No module named ‘psycopg2’ Error in Jupyter?

In most cases, Jupyter Notebook works in the anaconda environment. Use the conda install psycopg2 command to install the package in Jupyter. If it’s not working on Anaconda Environment, you have to find the location of the working environment and install the package there.

Conclusion

So, in this way, one can resolve the import error related to the PostgreSQL connection. A quick tip is to keep in mind the requisites we should follow before executing any program. We can permanently activate a python virtual window and maintain that virtual window according to the project’s needs. Now it’s your time to leverage the DB connection and create fantastic projects with ‘psycopg2’ and PostgreSQL.

Bon Codage!

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Comments

@hankuksui

ruiztulio

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Oct 11, 2017

@ruiztulio

We need to install postgresql-server-dev so the pg_config commands shows the proper version, at the moment it shows 10.0 even when only the 9.6 is installed. This issue was fixed in pycopg 2.7, but not in the previous versions: psycopg/psycopg2#594

This patch only apply for the images that uses older pycopg versions, that is 8.0 and 9.0 because 10 and 11 use 2.7.

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This was referenced

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@lym
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johnbradley

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@johnbradley

Installing psycopg2 failes on circle due to postgres 10.0 version installed there.
```
Downloading psycopg2-2.6.2.tar.gz (376kB)
...
Error: could not determine PostgreSQL version from '10.0'
```
Bug Details: psycopg/psycopg2#594
We had this issue with iMADS already: Duke-GCB/iMADS#137

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@felixzhuologist

@kristinyim

* fix build

* amend

* Bump psycopg2 version

Bug (psycopg/psycopg2#594) which fixed in
2.7.1

* use python image instead of node image

* don't use --user inside virtualenv

* fix javascript linting

* fix js tests

* silence messages for testing

* fix exams test

* fix travis config

* move babel preset to prod dependencies

* fix docs build

* add delete student endpoint

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davidxia

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@davidxia

to fix this error on travis-ci.com that occurred when pip installing reqs.
See psycopg/psycopg2#594 (comment).

```
Collecting psycopg2==2.6.1 (from -r requirements.txt (line 58))
  Downloading https://files.pythonhosted.org/packages/86/fd/cc8315be63a41fe000cce20482a917e874cdc1151e62cb0141f5e55f711e/psycopg2-2.6.1.tar.gz (371kB)
    100% |████████████████████████████████| 378kB 3.6MB/s
    Complete output from command python setup.py egg_info:
    running egg_info
    creating pip-egg-info/psycopg2.egg-info
    writing pip-egg-info/psycopg2.egg-info/PKG-INFO
    writing top-level names to pip-egg-info/psycopg2.egg-info/top_level.txt
    writing dependency_links to pip-egg-info/psycopg2.egg-info/dependency_links.txt
    writing manifest file 'pip-egg-info/psycopg2.egg-info/SOURCES.txt'
    Error: could not determine PostgreSQL version from '10.1'

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-NRfbIi/psycopg2/
The command "pip install -U -r requirements.txt" failed and exited with 1 during .
```

davidxia

added a commit
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Oct 23, 2018

@davidxia

to fix this error on travis-ci.com that occurred when pip installing reqs.
See psycopg/psycopg2#594 (comment).

```
Collecting psycopg2==2.6.1 (from -r requirements.txt (line 58))
  Downloading https://files.pythonhosted.org/packages/86/fd/cc8315be63a41fe000cce20482a917e874cdc1151e62cb0141f5e55f711e/psycopg2-2.6.1.tar.gz (371kB)
    100% |████████████████████████████████| 378kB 3.6MB/s
    Complete output from command python setup.py egg_info:
    running egg_info
    creating pip-egg-info/psycopg2.egg-info
    writing pip-egg-info/psycopg2.egg-info/PKG-INFO
    writing top-level names to pip-egg-info/psycopg2.egg-info/top_level.txt
    writing dependency_links to pip-egg-info/psycopg2.egg-info/dependency_links.txt
    writing manifest file 'pip-egg-info/psycopg2.egg-info/SOURCES.txt'
    Error: could not determine PostgreSQL version from '10.1'

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-NRfbIi/psycopg2/
The command "pip install -U -r requirements.txt" failed and exited with 1 during .
```

davidxia

added a commit
to davidxia/courtlistener
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Oct 24, 2018

@davidxia

to fix this error on travis-ci.com that occurred when pip installing reqs.
See psycopg/psycopg2#594 (comment).

```
Collecting psycopg2==2.6.1 (from -r requirements.txt (line 58))
  Downloading https://files.pythonhosted.org/packages/86/fd/cc8315be63a41fe000cce20482a917e874cdc1151e62cb0141f5e55f711e/psycopg2-2.6.1.tar.gz (371kB)
    100% |████████████████████████████████| 378kB 3.6MB/s
    Complete output from command python setup.py egg_info:
    running egg_info
    creating pip-egg-info/psycopg2.egg-info
    writing pip-egg-info/psycopg2.egg-info/PKG-INFO
    writing top-level names to pip-egg-info/psycopg2.egg-info/top_level.txt
    writing dependency_links to pip-egg-info/psycopg2.egg-info/dependency_links.txt
    writing manifest file 'pip-egg-info/psycopg2.egg-info/SOURCES.txt'
    Error: could not determine PostgreSQL version from '10.1'

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-NRfbIi/psycopg2/
The command "pip install -U -r requirements.txt" failed and exited with 1 during .
```

davidxia

added a commit
to davidxia/courtlistener
that referenced
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Oct 24, 2018

@davidxia

to fix this error on travis-ci.com that occurred when pip installing reqs.
See psycopg/psycopg2#594 (comment).

```
Collecting psycopg2==2.6.1 (from -r requirements.txt (line 58))
  Downloading https://files.pythonhosted.org/packages/86/fd/cc8315be63a41fe000cce20482a917e874cdc1151e62cb0141f5e55f711e/psycopg2-2.6.1.tar.gz (371kB)
    100% |████████████████████████████████| 378kB 3.6MB/s
    Complete output from command python setup.py egg_info:
    running egg_info
    creating pip-egg-info/psycopg2.egg-info
    writing pip-egg-info/psycopg2.egg-info/PKG-INFO
    writing top-level names to pip-egg-info/psycopg2.egg-info/top_level.txt
    writing dependency_links to pip-egg-info/psycopg2.egg-info/dependency_links.txt
    writing manifest file 'pip-egg-info/psycopg2.egg-info/SOURCES.txt'
    Error: could not determine PostgreSQL version from '10.1'

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-NRfbIi/psycopg2/
The command "pip install -U -r requirements.txt" failed and exited with 1 during .
```

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AlexRiina

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Jan 18, 2019

psycopg2<2.7 looks for the a postgres version like x.xx which
unfortunately crashes trying to match 10.xx see
psycopg/psycopg2#594

jrdh

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Oct 2, 2019

@jrdh

This is because of this: psycopg/psycopg2#594.
On 18.04 libpq-dev installs a pg_config which reports 10.10 which psycopg2
version 2.4.5 (good lord, how old?!) can't cope with and fails to install.
There may be a way of resolving this by installing some other version of
libpq-dev but I haven't found it yet, and I think this is the simplest
solution anyway.

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@abitrolly

A common error you may encounter when using Python is modulenotfounderror: no module named ‘psycopg2’.

This error occurs when the Python interpreter cannot detect the Psycopg library in your current environment.

You can install Psycopg2 in Python 3 with python3 -m pip install psycopg2-binary.

This tutorial goes through the exact steps to troubleshoot this error for the Windows, Mac and Linux operating systems.


Table of contents

  • ModuleNotFoundError: no module named ‘psycopg2’
    • What is ModuleNotFoundError?
    • What is Psycopg2?
  • Always Use a Virtual Environment to Install Packages
    • How to Install Psycopg2 on Windows Operating System
      • Psycopg2 installation on Windows Using pip
    • How to Install Psycopg2 on Mac Operating System using pip
    • How to Install Psycopg2 on Linux Operating Systems
      • Installing pip for Ubuntu, Debian, and Linux Mint
      • Installing pip for CentOS 8 (and newer), Fedora, and Red Hat
      • Installing pip for CentOS 6 and 7, and older versions of Red Hat
      • Installing pip for Arch Linux and Manjaro
      • Installing pip for OpenSUSE
      • Psycopg2 installation on Linux with Pip
  • Installing Psycopg2 Using Anaconda
    • Check Psycopg2 Version
  • Summary

ModuleNotFoundError: no module named ‘psycopg2’

What is ModuleNotFoundError?

The ModuleNotFoundError occurs when the module you want to use is not present in your Python environment. There are several causes of the modulenotfounderror:

The module’s name is incorrect, in which case you have to check the name of the module you tried to import. Let’s try to import the re module with a double e to see what happens:

import ree
---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
1 import ree

ModuleNotFoundError: No module named 'ree'

To solve this error, ensure the module name is correct. Let’s look at the revised code:

import re

print(re.__version__)
2.2.1

You may want to import a local module file, but the module is not in the same directory. Let’s look at an example package with a script and a local module to import. Let’s look at the following steps to perform from your terminal:

mkdir example_package

cd example_package

mkdir folder_1

cd folder_1

vi module.py

Note that we use Vim to create the module.py file in this example. You can use your preferred file editor, such as Emacs or Atom. In module.py, we will import the re module and define a simple function that prints the re version:

import re

def print_re_version():

    print(re.__version__)

Close the module.py, then complete the following commands from your terminal:

cd ../

vi script.py

Inside script.py, we will try to import the module we created.

import module

if __name__ == '__main__':

    mod.print_re_version()

Let’s run python script.py from the terminal to see what happens:

Traceback (most recent call last):
  File "script.py", line 1, in ≺module≻
    import module
ModuleNotFoundError: No module named 'module'

To solve this error, we need to point to the correct path to module.py, which is inside folder_1. Let’s look at the revised code:

import folder_1.module as mod

if __name__ == '__main__':

    mod.print_re_version()

When we run python script.py, we will get the following result:

2.2.1

Lastly, you can encounter the modulenotfounderror when you import a module that is not installed in your Python environment.

What is Psycopg2?

Psycopg2 is a PostgreSQL database adapter for Python. It provides an API to connect to an external database.

The simplest way to install psycopg2 is to use the package manager for Python called pip. The following installation instructions are for the major Python version 3.

Always Use a Virtual Environment to Install Packages

It is always best to install new libraries within a virtual environment. You should not install anything into your global Python interpreter when you develop locally. You may introduce incompatibilities between packages, or you may break your system if you install an incompatible version of a library that your operating system needs. Using a virtual environment helps compartmentalize your projects and their dependencies. Each project will have its environment with everything the code needs to run. Most ImportErrors and ModuleNotFoundErrors occur due to installing a library for one interpreter and trying to use the library with another interpreter. Using a virtual environment avoids this. In Python, you can use virtual environments and conda environments. We will go through how to install psycopg2 with both.

How to Install Psycopg2 on Windows Operating System

First, you need to download and install Python on your PC. Ensure you select the install launcher for all users and Add Python to PATH checkboxes. The latter ensures the interpreter is in the execution path. Pip is automatically on Windows for Python versions 2.7.9+ and 3.4+.

You can check your Python version with the following command:

python3 --version

You can install pip on Windows by downloading the installation package, opening the command line and launching the installer. You can install pip via the CMD prompt by running the following command.

python get-pip.py

You may need to run the command prompt as administrator. Check whether the installation has been successful by typing.

pip --version

Psycopg2 installation on Windows Using pip

To install psycopg2, first create the virtual environment. The environment can be any name, in this we choose “env”:

virtualenv env

You can activate the environment by typing the command:

envScriptsactivate

You will see “env” in parenthesis next to the command line prompt. You can install psycopg2 within the environment by running the following command from the command prompt.

python3 -m pip install psycopg2-binary

We use python -m pip to execute pip using the Python interpreter we specify as Python. Doing this helps avoid ImportError when we try to use a package installed with one version of Python interpreter with a different version. You can use the command which python to determine which Python interpreter you are using.

How to Install Psycopg2 on Mac Operating System using pip

Open a terminal by pressing command (⌘) + Space Bar to open the Spotlight search. Type in terminal and press enter. To get pip, first ensure you have installed Python3:

python3 --version
Python 3.8.8

Download pip by running the following curl command:

curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py

The curl command allows you to specify a direct download link. Using the -o option sets the name of the downloaded file.

Install pip by running:

python3 get-pip.py

To install psycopg2, first create the virtual environment:

python3 -m venv env

Then activate the environment using:

source env/bin/activate 

You will see “env” in parenthesis next to the command line prompt. You can install psycopg2 within the environment by running the following command from the command prompt.

python3 -m pip install psycopg2-binary

How to Install Psycopg2 on Linux Operating Systems

All major Linux distributions have Python installed by default. However, you will need to install pip. You can install pip from the terminal, but the installation instructions depend on the Linux distribution you are using. You will need root privileges to install pip. Open a terminal and use the commands relevant to your Linux distribution to install pip.

Installing pip for Ubuntu, Debian, and Linux Mint

sudo apt install python-pip3

Installing pip for CentOS 8 (and newer), Fedora, and Red Hat

sudo dnf install python-pip3

Installing pip for CentOS 6 and 7, and older versions of Red Hat

sudo yum install epel-release

sudo yum install python-pip3

Installing pip for Arch Linux and Manjaro

sudo pacman -S python-pip

Installing pip for OpenSUSE

sudo zypper python3-pip

Psycopg2 installation on Linux with Pip

To install psycopg2, first create the virtual environment:

python3 -m venv env

Then activate the environment using:

source env/bin/activate 

You will see “env” in parenthesis next to the command line prompt. You can install psycopg2 within the environment by running the following command from the command prompt.

Once you have activated your virtual environment, you can install psycopg2 using:

python3 -m pip install psycopg2-binary

Installing Psycopg2 Using Anaconda

Anaconda is a distribution of Python and R for scientific computing and data science. You can install Anaconda by going to the installation instructions. Once you have installed Anaconda, you can create a virtual environment and install psycopg2.

To create a conda environment you can use the following command:

conda create -n psycopg2 python=3.8

You can specify a different Python 3 version if you like. Ideally, choose the latest version of Python. Next, you will activate the project container. You will see “psycopg2” in parentheses next to the command line prompt.

source activate psycopg2

Now you’re ready to install psycopg2 using conda.

Once you have activated your conda environment, you can install psycopg2 using the following command:

conda install -c anaconda psycopg2

Check Psycopg2 Version

Once you have successfully installed psycopg2, you can check its version. If you used pip to install psycopg2, you can use pip show from your terminal.

python3 -m pip show psycopg2-binary
Name: psycopg2-binary
Version: 2.9.3
Summary: psycopg2 - Python-PostgreSQL Database Adapter

Second, within your python program, you can import psycopg2 and then reference the __version__ attribute:

import psycopg2
print(psycopg2.__version__)
2.9.3

If you used conda to install psycopg2, you could check the version using the following command:

conda list -f psycopg2
# Name                    Version                   Build  Channel
psycopg2                  2.8.5            py38hddc9c9b_0    anaconda

Summary

Congratulations on reading to the end of this tutorial. The modulenotfounderror occurs if you misspell the module name, incorrectly point to the module path or do not have the module installed in your Python environment. If you do not have the module installed in your Python environment, you can use pip to install the package. However, you must ensure you have pip installed on your system. You can also install Anaconda on your system and use the conda install command to install psycopg2.

Go to the online courses page on Python to learn more about Python for data science and machine learning.

For further reading on missing modules in Python, go to the article:

  • How to Solve Python ModuleNotFoundError: no module named ‘urllib2’.
  • How to Solve ModuleNotFoundError: no module named ‘plotly’.
  • How to Solve Python ModuleNotFoundError: no module named ‘boto3’.

Have fun and happy researching!

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Тема: Проблемы с установкой psycopg2  (Прочитано 4108 раз)

0 Пользователей и 1 Гость просматривают эту тему.

Оффлайн
dimanoga

Всем привет! С linux  и python только знакомлюсь, нужна ваша помощь.
Пробую

pip install psycopg2
В ответ:

Error: b'You need to install postgresql-server-dev-X.Y for building a server-side extension or libpq-dev for building a client-side application.n'
Пытаюсь установить libpq-dev

sudo apt-get install libpq-dev

libpq-dev : Зависит: libpq5 (= 10.12-0ubuntu0.18.04.1) но 12.3-1.pgdg18.04+1 должен быть установлен
Хотя версия последняя стоит.
Удалял, потом ставил заново — реузльтата 0.
Перерыл все форумы, но тоже не особо помогло.

Что делать?


Оффлайн
archuser

Что делать?

У Вас Ubuntu 18.04 и следовательно libpq5 версии 10.12-0*. Вы же пытаетесь установить psycopg2 из альтернативного репозитория, что приводит к рассогласованности неудовлетворенных зависимостей, установленных из официальных репозиториев Ubuntu. Вывод: либо вручную разрешаете все зависимости, что может привести к неработоспособности как отдельных приложений, так и все системы в целом, либо устанавливаете штатный пакет psycopg2:

sudo apt install python-psycopg2 #для python2
sudo apt install python3-psycopg2 #для python3


Оффлайн
dimanoga

sudo apt install python3-psycopg2 #для python3

Установил для python3
при запуске django

python manage.py runserver

learnPython/venv2/lib/python3.8/site-packages/django/db/backends/postgresql/base.py", line 29, in <module>
    raise ImproperlyConfigured("Error loading psycopg2 module: %s" % e)
django.core.exceptions.ImproperlyConfigured: Error loading psycopg2 module: No module named 'psycopg2'


Оффлайн
archuser

dimanoga, а чего Вы ждете от винегрета в Вашей системе? Вручную установили python версии 3.8, в то время как в Ubuntu 18.04 python штатно представлен версией 3.6.7. И потому установка ранее предложенного пакета python3-psycopg2 не дала результата. Я Вам предлагаю отказаться от самодеятельности и использоваться только пакеты из официально поддерживаемых репозиториев Вашего дистрибутива.


Оффлайн
dimanoga

dimanoga, а чего Вы ждете от винегрета в Вашей системе? Вручную установили python версии 3.8, в то время как в Ubuntu 18.04 python штатно представлен версией 3.6.7. И потому установка ранее предложенного пакета python3-psycopg2 не дала результата. Я Вам предлагаю отказаться от самодеятельности и использоваться только пакеты из официально поддерживаемых репозиториев Вашего дистрибутива.

Хорошо. Что сделать чтобы заработало.
Откатить python до 3.6.7?


Оффлайн
archuser

Откатить python до 3.6.7?

Вы правильно поняли мой посыл.


Оффлайн
dimanoga


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PostgreSQL database is the most used SQL database. Psycopg2 is the most popular PostgreSQL database adapter for the Python programming language. Using it you can connect, update, insert, more efficiently on your database. However, sometimes many programmers find no module named psycopg2 error. And in this entire tutorial, you will know how to fix no module named psycopg2.

Most of the time this error comes when you have not properly installed the psycopg3 in your system. For example, if I type the following code and run it will get the No module named psycopg2 error.

import psycopg2

You will get the following error when you run the code.

ModuleNotFoundError: no module named "psycopg2 "

Methods to Fix the psycopg2 error

Now the questions come about how to fix this error. There are many methods to fix it and it depends upon your system.

Method 1: Install the psycopg2-binary

The first method that can solve this error is to install psycopg2-binary instead of psycopg2. You can install it using the pip command.

For python 2.xx version

pip install psycopg2-binary

For python 3.xx version

pip3 install psycopg2-binary

It will successfully install the module and now you will run the code then you will not get the No module named psycopg2 error.

Note: To check the python version on your system run the below command on your system terminal.

python --version

Checking the version of python on windows

Checking the version of python on windows

Method 2: Update the pip command

Sometimes you are unable to install psycopg2 due to the corrupted or outdated pip command.  To fix the error you have to install or update the pip command.

The pip command comes with the python. But in case you want to install it then you will use the following command. But before that, you have to download the get-pip.py. After that go to the downloaded directory and Copy the below command and run the python file on your terminal.

python get-pip.py

It will successfully install the pip package on your system. Now using it install the psycopg2. It will successfully remove the No module named psycopg2 error.

These are the two popular methods to solve the No module  psycopg2 error. I hope using this tutorial you have solved the issue. Even if the issue remains then you can contact us for more help.

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