Nrthugu

Here is the code:

static void Client_MqttMsgPublishReceived(object sender, MqttMsgPublishEventArgs e) //Event Handler

{

   Time timeToSend = JsonConvert.DeserializeObject<Time>(Encoding.UTF8.GetString(e.Message));



   Task.Run(async () => await SendToMySql(timeToSend));            

}

In the SendToMySql method, it basically a insert, as follows:

private static async Task SendToMySql(Time timeToSend)

{

        try

        {

            var connection = new MySqlConnection(string.Format(configuration["MySql:ConnectionString"], configuration["MySql:DataBaseName"]));

            await connection.OpenAsync();

            string query = "insert into resource_log (resource_value_log, creation_date) values ('" + timeToSend.Message + "',STR_TO_DATE( '" + DateTime.Now + "', '%d/%m/%Y %H:%i:%s'))";

            var cmd = new MySqlCommand(query, connection);

            await cmd.ExecuteReaderAsync();

            await connection.CloseAsync();

        }

        catch (Exception ex)

        {

            Console.WriteLine(ex.Message.ToString());

        }

 } 

I called this method using the Task.Run() cause i wanted it too run asynchronous if necessary. But it throws the following exception:

"Unable to connect to any of the specified MySQL hosts."

Here is the inner Exception:

Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.

Some of the data was actually inserted into the MySql.

I am new to asynchronous and parallel programming and I coded this way but I wonder if this is the right way to do a asynchronous query on MySql. I did it the same way as this, but with MongoDb, and it worked fine. Hope you guys can help me. Thanks.

It’s a longstanding bug in Connector/NET (MySql.Data) that none of the Async methods actually execute asynchronously: bug 70111.

To fix this, you can switch to an alternative ADO.NET MySQL library, which is 100% async: MySqlConnector on GitHub and NuGet.

Although MySqlConnector does implement a CloseAsync method, the default implementation synchronously returns the open connection to the connection pool, so I would recommend omitting the CloseAsync call and just using a using block to Dispose the connection when you're done with it:

using (var connection = new MySqlConnection(string.Format(configuration["MySql:ConnectionString"], configuration["MySql:DataBaseName"])))

{

    await connection.OpenAsync();

    var query = "...";

    using (var cmd = new MySqlCommand(query, connection))

        await cmd.ExecuteReaderAsync();

}