How to get pgbouncer stats with .NET (c#) - postgresql

Question

I want to show some pgbouncer stats in a simple wpf client (npgsql), but I can't connect to pgbouncer. The connect to a postgresql database via pgbouncer is working well, but the connect to pgbouncer admin database is not. With the used credentials I don't have any problems to connect with psql.
The Code:
var connString = "Server=X.X.X.X;Port=6432;User Id=pgbouncer;Password=myPw;Database=pgbouncer;";
using (var con = new NpgsqlConnection(connString))
{
await con.OpenAsync();
return (await new NpgsqlCommand(sql, con).ExecuteScalarAsync()).ToString();
}
I get the error 08P01: unsupported pkt type: 80 on opening the connection.
In this post the problem could be solved by an extra parameter in the jdbc connectionstring, but this parameter seems unavailable in a npgsql connectionstring.
How can I get some pgbouncer stats in a c# client?
EDIT:
In the meantime I tried Devart provider (Express edition), but it don't work too, because the provider commits a SELECT VERSION(); during the connect, and the pgbouncer database don't understand this statement => Exception. In pgbouncer forum I can't find a solution as well.
I can't believe that this task apparently is so rarely. I'm really surprised.

Answer 1

PostgreSQL has two query protocols at the wire level - the simple protocol and the extended protocol; it seems that the pgbouncer admin interface supports only the simple protocol, but Npgsql only supports the extended protocol. That unfortunately means that the two are incompatible at the moment.
This issue tracks adding support for the simple protocol to Npgsql.