SHOW name
SHOW ALL
The name of a run-time parameter. See SET for a list.
Show all current session parameters.
SHOW will display the current setting of a run-time parameter. These variables can be set using the SET statement or are determined at server start.
Message returned if variable does not stand for an existing parameter.
You must be a superuser to be allowed to see certain settings.
If the TZ or PGTZ environment variable is not set.