Postgresql Foreign data wrapper error Non-superuser cannot connect if the server does not request a password

Question

We are using postgres_fdw extension to access views of another database. I have tested accessing foreign tables on 2 different PostgreSQL servers, it's working on one server and another server is throwing below error

SQL Error [2F003]: ERROR: password is required
  Detail: Non-superuser cannot connect if the server does not request a password.
  Hint: Target server's authentication method must be changed.

i have checked pg_hba.conf file and one server is using trust method for local access and still not getting error however another server is getting the error with trust and md5 both options.

below are conf files of both servers

1. The server which is throwing error

2. server where query is running without any error

Below is my script to create a foreign server

DO $$
Begin 



if not exists(select 1 from pg_foreign_server where srvname='fdw_dxpcore') then 

If not Exists (select * from pg_user where usename='pgfwduser') then
create role pgfwduser with login password 'test@123';
end if;

If Exists (select * from pg_user where usename='pgfwduser') then



IF Exists (select * from pg_database where datname = 'ars') Then
grant connect on database ars to pgfwduser;
End IF;

grant usage on schema public to pgfwduser;
GRANT SELECT ON all tables in schema public TO pgfwduser;
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES to pgfwduser;
End IF;



-- create foreign data wrapper extension 
CREATE EXTENSION if not exists postgres_fdw;

-- create foreign servers for dxpcore
if not exists(select 1 from pg_foreign_server where srvname='fdw_dxpcore') then 
CREATE SERVER fdw_dxpcore
        FOREIGN DATA WRAPPER postgres_fdw
        OPTIONS (host 'localhost', port '5432', dbname 'dxpcore', fetch_size '50000');
end if;


--- assign foreign table access to 
if exists (select 1 from pg_roles where rolname='postgres') then
if not exists (select * from information_schema.user_mappings where foreign_server_name = 'fdw_dxpcore' and authorization_identifier = 'postgres') Then
CREATE USER MAPPING  FOR postgres
        SERVER fdw_dxpcore
        OPTIONS (user 'pgfwduser',password 'test@123');
End IF;     
end if;

/*Import Foreign Tables*/

IMPORT FOREIGN SCHEMA public LIMIT TO (v_resguestids,v_resguestids_shore_ship)  
    FROM SERVER fdw_dxpcore INTO public;

if exists (select 1 from pg_roles where rolname='pgappuser') then
if not exists (select * from information_schema.user_mappings where foreign_server_name = 'fdw_dxpcore' and authorization_identifier = 'pgappuser') Then
CREATE USER MAPPING  FOR pgappuser
        SERVER fdw_dxpcore
        OPTIONS (user 'pgfwduser',password 'test@123');
End IF;     
end if;

End if;



If Exists (select * from pg_user where usename='pgappuser') Then

        ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT, INSERT, UPDATE, DELETE ON TABLES to pgappuser;
        ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT, USAGE ON SEQUENCES to pgappuser;
        ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT EXECUTE ON FUNCTIONS to pgappuser;

        GRANT  USAGE  ON SCHEMA public TO  pgappuser;
        GRANT SELECT, INSERT, UPDATE, DELETE ON ALL TABLES IN SCHEMA public TO  pgappuser;
        GRANT USAGE, SELECT ON ALL SEQUENCES IN SCHEMA public TO pgappuser;
        GRANT EXECUTE ON ALL FUNCTIONs IN SCHEMA public TO pgappuser;

End IF;




If Exists (select * from pg_user where usename='pgfwduser') Then

        ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES to pgfwduser;
        ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT, USAGE ON SEQUENCES to pgfwduser;
        ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT EXECUTE ON FUNCTIONS to pgfwduser;

        GRANT  USAGE  ON SCHEMA public TO  pgfwduser;
        GRANT SELECT ON ALL TABLES IN SCHEMA public TO  pgfwduser;
        GRANT USAGE, SELECT ON ALL SEQUENCES IN SCHEMA public TO pgfwduser;
        GRANT EXECUTE ON ALL FUNCTIONs IN SCHEMA public TO pgfwduser;
End IF;




End $$;

Answer 1

i have checked pg_hba.conf file and one server is using trust method for local access and still not getting error however another server is getting the error with trust and md5 both options.

and

 OPTIONS (host 'localhost', port '5432', dbname 'dxpcore', fetch_size '50000');

'localhost' is not the same thing as 'local'. It is instead the same thing as '127.0.0.1' (unless you did something strange with your network config.) The machine not throwing errors is not using 'trust', because it is not connecting through unix sockets. It is connecting through TCP loopback device.