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.)
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