error connecting: Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool

public void enqueue(object e)
{
    try
    {
        DataChangeEventArgs e113 = (DataChangeEventArgs)e;
        resetdatasource();
        for (i=0; i < e113.sts.Length; i++)
        {
            int hour113 = e113.sts[i].TimeStampNet.Hour;
            int minute113 = e113.sts[i].TimeStampNet.Minute;
            int second113 = e113.sts[i].TimeStampNet.Second;
            int millisecond113 = e113.sts[i].TimeStampNet.Millisecond;
            int year113 = e113.sts[i].TimeStampNet.Year;
            int month113 = e113.sts[i].TimeStampNet.Month;
            int day113 = e113.sts[i].TimeStampNet.Day;
            DateTime sdate113 = new DateTime(year113, month113, day113, hour113, minute113, second113, millisecond113);

            DataRow row1 = dt.NewRow();
            row1["itemID"] = e113.sts[i].HandleClient;
            row1["paramvalue"] = convert.ToString(e113.sts[i].DataValue);
            row1["date_logged1"] = sdate113.ToString("dd-MM-yyyy HH:mm:ss.fff");
            row1["Quality"] = e113.sts[i].Quality;
            row1["date_logged"] = DateTime.FromFileTime(e113.sts[i].TimeStamp);
            dt.Rows.Add(row1);
        }
        var threadupdate = new Thread(update);//start new thread & instance
        threadupdate.Start(dt);
    }
    catch { }
}

public void update(object dtnew)
        {
            try
            {
                   MySqlConnection con = new MySqlConnection(LocalConnection.GetLocalConnetionStringmysql());
                    DataSet oldvalueds=new DataSet();
                    DataTable newupdateddata = new DataTable();
                    MySqlDataAdapter da;
                
                    
                    MySqlTransaction trans;
                    if (con.State == ConnectionState.Closed)
                        con.Open();//throws exception
                    trans = con.BeginTransaction();
                    da = new MySqlDataAdapter();
                    da.InsertCommand = new MySqlCommand("INSERT INTO parameter (itemID,paramvalue, date_logged1,Quality,date_logged) " +
                                           "VALUES (@itemID, @paramvalue,@date_logged1,@Quality,@date_logged)" +
                                           "ON DUPLICATE KEY UPDATE " +
                                           "itemID=VALUES(itemID),paramvalue=VALUES(paramvalue),date_logged1=VALUES(date_logged1),Quality=VALUES(Quality),date_logged=VALUES(date_logged)", con);

                    da.InsertCommand.Parameters.Add("@itemID", MySqlDbType.VarChar, 250, "itemID");
                    da.InsertCommand.Parameters.Add("@paramvalue", MySqlDbType.VarChar, 250, "paramvalue");
                    da.InsertCommand.Parameters.Add("@date_logged1", MySqlDbType.VarChar, 250, "date_logged1");
                    da.InsertCommand.Parameters.Add("@Quality", MySqlDbType.VarChar, 250, "Quality");
                    da.InsertCommand.Parameters.Add("@date_logged", MySqlDbType.VarChar, 250, "date_logged");
                  
                   da.InsertCommand.Transaction = trans;
                     DataTable newupdateddt = (DataTable)dtnew;
                  int k = da.Update(newupdateddt);//exception thrown 2nd
                       trans.Commit();
                       con.Close();

              }
        
            catch(Exception ex) {
             
               }
            finally
            {

              
            }
        }

It will be thrown an exception like "Error connecting: Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached."

I will be set the timeout=200 in connection string this exception was thrown
"Deadlock found when trying to get lock; try restarting transaction"

Thanks in advance

Tags: C#, .NET, MySQL