This is the default example configuration of pgsql provided by Postfix. This config file was generated by Postfix running on CentOS 8.
It is located under: /etc/postfix/dynamicmaps.cf.d/pgsql
pgsql /usr/lib64/postfix/postfix-pgsql.so dict_pgsql_open
Download the raw file with wget or curl
wget -O pgsql.example http://exampleconfig.com/static/raw/postfix/centos8/etc/postfix/dynamicmaps.cf.d/pgsql
curl http://exampleconfig.com/static/raw/postfix/centos8/etc/postfix/dynamicmaps.cf.d/pgsql > pgsql.example
Other config files you might find useful