---
title: "Environment Variables"
id: plpython-envar
pg_version: "20devel"
---

<a id="plpython-envar"></a>

## 44.12. Environment Variables

Some of the environment variables that are accepted by the Python interpreter can also be used to affect PL/Python behavior. They would need to be set in the environment of the main PostgreSQL server process, for example in a start script. The available environment variables depend on the version of Python; see the Python documentation for details. At the time of this writing, the following environment variables have an affect on PL/Python, assuming an adequate Python version: 
- PYTHONHOME
- PYTHONPATH
- PYTHONY2K
- PYTHONOPTIMIZE
- PYTHONDEBUG
- PYTHONVERBOSE
- PYTHONCASEOK
- PYTHONDONTWRITEBYTECODE
- PYTHONIOENCODING
- PYTHONUSERBASE
- PYTHONHASHSEED

 (It appears to be a Python implementation detail beyond the control of PL/Python that some of the environment variables listed on the `python` man page are only effective in a command-line interpreter and not an embedded Python interpreter.)