System.Threading.Thread.Sleep - Any legit reason to have in production code?

Question

I'm doing some code cleanup, and I came across a few instances of

System.Threading.Thread.Sleep(2000);

These are all in Button Click events.

I can't think of any reason why this would be in production code?

Am I missing something?

EDIT --

Full Code Block (some things changed, but steps are the same) -- And yes, I think it sucks the way it's done too ha

    protected void btnSubmit_Click(object sender, ImageClickEventArgs e)
{
    try
    {
        System.Threading.Thread.Sleep(2000);

        string guid = Profile.Auth.GUID;

        activity act = new activity();

        try
        {
            if (checkbox.Checked)
            {
                add.activity(true);

            }
            else
            {
                act.AddActivity(false)
            }

            LoadData();
        }
        catch (Exception ex)
        {
            Response.Write(ex);
        }
    }
    catch { }
}

Answer 1

It looks like a version of the speed-up loop. There are no standard reasons for this - most likely someone was compensating for some sort of timing issue.

Answer 2

The only reason would be to slow things down (maybe for testing?), so I don't think it should be in production.

Answer 3

A possible reason is a qick hack to make a short delay before displaying the result of something.

The problem with having a Sleep in the user interface code is that the user interface gets unresponsive. If you want a delay like that you would use a timer control. It's a bit more work, but the user experience is better in the end.

Answer 4

I have heard of some people putting in sleep code to compensate for animations/visual effects on the page (progress bars, etc.) after an event is called.

Answer 5

I've used Thread.Sleep for waiting while polling for other actions to finish (pass something off for calculation, poll for completion every quarter second). That said, I can't think of a reason to have: that long of a pause, in a button handler, in a web app. Can't really judge without surrounding code though.

Answer 6

Does the system trigger any back end processing service before going to sleep and is looking for the updated data / cache to be invalidated after the sleep?

Answer 7

Maybe they were copying and pasting code, like this article that uses Thread.Sleep on the Code Project.

This does sound like an entry for daily WTF!

Answer 8

I've seen people use a sleep to delay the request/response cycle of password submissions and thereby prevent brute force attacks. Of course a lockout policy would acheive the same thing rather than temporarily pulling the plug on the whole thread.

Answer 9

I am not sure of that code, put it another way, this code System.Threading.Sleep(0) causes the CPU to context switch, i.e. flush the code..but for 2000 milli-seconds or 2 seconds, sounds like the programmer was waiting for a period before obtaining the guid from another class presumably called Profile....it smells of a race condition in there, I would question why wait for 2 seconds before proceeding....

Just my 2cents,

Hope this helps, Best regards, Tom.