=# CREATE TABLE dump (
   id   bigserial primary key,
   data jsonb     not null
);

=# SELECT data FROM dump;

upstream postgresql {
    postgres_server localhost dbname=default user=user password=secret;
}

server {
    listen 80;

    location /postgresql/ {
        rds_json          on;

        postgres_pass     postgresql;
        postgres_query    HEAD GET "SELECT data FROM dump"
        postgres_rewrite  no_rows 410;
        postgres_output   rds;
    }
}

[{"data":"{"id": "00ce160e5cbb49b9bc2ee6f243f87841", "name": "foo"}"}]