The connection service file allows libpq connection parameters to be associated with a single service name. That service name can then be specified by a libpq connection, and the associated settings will be used. This allows connection parameters to be modified without requiring a recompile of the libpq application. The service name can also be specified using the PGSERVICE environment variable.

The connection service file can be a per-user service file at ~/.pg_service.conf or the location specified by the environment variable PGSERVICEFILE, or it can be a system-wide file at `pg_config --sysconfdir`/pg_service.conf or in the directory specified by the environment variable PGSYSCONFDIR. If service definitions with the same name exist in the user and the system file, the user file takes precedence.

The file uses an “INI file” format where the section name is the service name and the parameters are connection parameters; see Section 33.1.2 for a list. For example:

# comment
[mydb]
host=somehost
port=5433
user=admin

An example file is provided at share/pg_service.conf.sample.

If more than one host option is present in the same section of the service file, it is interpreted as alternate servers for failover or load-balancing. See host option in the connection string.

For all other options, the first value takes precedence over later ones.

Options specified in the connection string, along with the service option, have precedence over values from the service file.