PostgreSQL - /etc/postgresql/17/main/pg_ident.conf

# PostgreSQL User Name Maps
# =========================
#
# ---------------
# Mapping Records
# ---------------
#
# Refer to the PostgreSQL documentation, chapter "Client
# Authentication" for a complete description.  A short synopsis
# follows.
#
# This file controls PostgreSQL user name mapping.  It maps external
# user names to their corresponding PostgreSQL user names.  Records
# are of the form:
#
# MAPNAME  SYSTEM-USERNAME  PG-USERNAME
#
# (The uppercase quantities must be replaced by actual values.)
#
# MAPNAME is the (otherwise freely chosen) map name that was used in
# pg_hba.conf.  SYSTEM-USERNAME is the detected user name of the
# client.  PG-USERNAME is the requested PostgreSQL user name.  The
# existence of a record specifies that SYSTEM-USERNAME may connect as
# PG-USERNAME.
#
# If SYSTEM-USERNAME starts with a slash (/), it will be treated as a
# regular expression.  Optionally this can contain a capture (a
# parenthesized subexpression).  The substring matching the capture
# will be substituted for \1 (backslash-one) if present in
# PG-USERNAME.
#
# PG-USERNAME can be "all", a user name, a group name prefixed with "+", or
# a regular expression (if it starts with a slash (/)).  If it is a regular
# expression, the substring matching with \1 has no effect.
#
# Multiple maps may be specified in this file and used by pg_hba.conf.
#
# No map names are defined in the default configuration.  If all
# system user names and PostgreSQL user names are the same, you don't
# need anything in this file.
#
# ---------------
# Include Records
# ---------------
#
# This file allows the inclusion of external files or directories holding
# more records, using the following keywords:
#
# include           FILE
# include_if_exists FILE
# include_dir       DIRECTORY
#
# FILE is the file name to include, and DIR is the directory name containing
# the file(s) to include.  Any file in a directory will be loaded if suffixed
# with ".conf".  The files of a directory are ordered by name.
# include_if_exists ignores missing files.  FILE and DIRECTORY can be
# specified as a relative or an absolute path, and can be double-quoted if
# they contain spaces.
#
# -------------------------------
# Miscellaneous
# -------------------------------
#
# This file is read on server startup and when the postmaster receives
# a SIGHUP signal.  If you edit the file on a running system, you have
# to SIGHUP the postmaster for the changes to take effect.  You can
# use "pg_ctl reload" to do that.

# Put your actual configuration here
# ----------------------------------

# MAPNAME       SYSTEM-USERNAME         PG-USERNAME