DB<142> sub merge_hr {  return  { %{$_[0]}, %{$_[1]} } } 

  DB<143> $conf3 = { map { $_ => merge_hr( $conf1->{$_}, $conf2->{$_} ) } keys %{merge_hr($conf1,$conf2)} }
=> 
{
  db => {
          host     => "localhost",
          name     => "pdte",
          password => "pdte_213456",
          port     => 5432,
          user     => "pdte_usr",
        },
}