PL/Python allows you to create stored procedures and functions in Python.
PL/Python is an untrusted language. This means that only a superuser can create procedures with it, but other users can use them. The default user created by Postgres.app is a superuser, so this shouldn’t be an issue in most cases.
To use PL/Python with Postgres.app, you first need to install Python using the installers from python.org.
Unfortunately, PostgreSQL can only link with a specific version of Python until PostgreSQL 18. Please install the correct version of Python, depending on the PostgreSQL version you are using:
| PostgreSQL Version | Python Version |
|---|---|
| PostgreSQL 18 | Python >= 3.9.x from python.org |
| PostgreSQL 17 | Python 3.13.x from python.org |
| PostgreSQL 16 | Python 3.12.x from python.org |
| PostgreSQL 15 | Python 3.11.x from python.org |
| PostgreSQL 14 | Python 3.9.x from python.org |
| PostgreSQL 13 | Python 3.8.x from python.org |
| PostgreSQL 12 and earlier | Python 2.7 (included with macOS) |
PostgreSQL 18 supports linking with any Python version >= 3.2 loaded from /Library/Frameworks/Python.framework.
The packages from python.org provide symlinks at this location since version 3.9. These point to another symlink,
/Library/Frameworks/Python.framework/Versions/Current, which can be changed to the preferred Python version with
something like sudo ln -svih 3.12 /Library/Frameworks/Python.framework/Versions/Current after the corresponding
package has been installed.
Installing or linking Python.frameworks to /Library/Frameworks/ from other sources like homebrew
should work as well, but is not tested nor supported:
sudo ln -s /opt/homebrew/Frameworks/Python.framework /Library/Frameworks/
Make sure to install the correct version of Python, then use the SQL command CREATE EXTENSION plpython3u; to enable the extension.