Question

I am new with C#. I am running a loop to send emails to subscribed users. I need to slow down the loop because I only want to send 10 email/second. Is using Thread.sleep good way to slow down the loop? please see code below.

            while (rdr.Read())
            {
                System.Threading.Thread.Sleep(100);

                //send email code here
            }

Thanks

Answer 1

Why don’t you have a System.Timers.Timer that fires up every second and sends up to ten messages from your message queue every second.

This way you really do have complete control over the process and are not guessing about speed/timings of your email sender.

Perhaps something like this:

public class EmailSender
{
    private System.Timers.Timer _timer = new Timer(1000);

    public EmailSender()
    {
        _timer.Elapsed += (object sender, ElapsedEventArgs args) => SendEmail();
    }

    public void StartSender()
    {
        _timer.Enabled = true;
    }

    public void SendEmail()
    {
        // you *may* want to stop your timer here in case the send of the ten overruns 1s.
        _timer.Enabled = false;

        // code here to send UP TO ten emails

        // re-enable timer, if you stopped it above.
        _timer.Enabled = true;
    }
}

In short – no – your original approach is not good.

• How do you know how long to make it sleep for to get 10 messages sent?
• What happens if the machine is running slowly anyway?
• What happens if you deploy to a faster machine?
• etc..