Bug #96561 multiple hosts error(Unable to connect to any of the specified MySQL hosts.)

• Submitted: 16 Aug 2019 2:22
• Modified: 16 Aug 2019 13:23
• Reporter: black 无
• Status: Duplicate
• Category: Connector / NET
• Severity: S3 (Non-critical)
• Version: 8.0.17
• OS: Any
• CPU Architecture: Any

[16 Aug 2019 2:22] black 无

Description:

ConnectionString: "server=server1,server2,server3;"
multiple hosts error(Unable to connect to any of the specified MySQL hosts.)

How to repeat:
using System;
using MySql.Data.MySqlClient;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            var conn1 = new MySqlConnection("server=server1;port=6446;user=root;password=123456;database=test;sslmode=none;");

            conn1.Open(); // connection ok

            var conn2 = new MySqlConnection("server=server1,server2,server3;port=6446;user=root;password=123456;database=test;sslmode=none;");

            conn2.Open(); // Unable to connect to any of the specified MySQL hosts.

            // StreamCreator.cs
            // GetTcpStream()
            // task = client.ConnectAsync(settings.Server, (int)settings.Port);

            // doc: Multiple hosts can be specified separated by commas. 
            // settings.Server = "server1,server2,server3" ??? bug

            Console.WriteLine("Hello World!");
        }
    }
}

[16 Aug 2019 11:58] black 无

My temporary solution
MySQL.Data/src/common/StreamCreator.cs:

    public static Stream GetStream(MySqlConnectionStringBuilder settings)
    {
      Exception exception = null;
      string[] servers = settings.Server.Split(',');
      settings = new MySqlConnectionStringBuilder(settings.ConnectionString);

      foreach (string server in servers)
      {
        settings.Server = server;
        try
        {
          switch (settings.ConnectionProtocol)
          {
            case MySqlConnectionProtocol.Tcp: return GetTcpStream(settings);
            case MySqlConnectionProtocol.UnixSocket: return GetUnixSocketStream(settings);        
            case MySqlConnectionProtocol.SharedMemory: return GetSharedMemoryStream(settings);
            case MySqlConnectionProtocol.NamedPipe: return GetNamedPipeStream(settings);
          }
          break;
        }
        catch (Exception e)
        {
          exception = e;
        }
      }

      if (null != exception) throw exception;
      throw new InvalidOperationException(Resources.UnknownConnectionProtocol);
    }

[16 Aug 2019 13:23] MySQL Verification Team

Hello black 无,

Thank you for the report.
Imho this is duplicate of Bug #81650, please see Bug #81650

Alternatively, you can try this - https://blogs.oracle.com/mysql/how-to%3a-using-replication-load-balancing-with-connectorne...

regards,
Umesh