Bug 523 - WebClient locks up under load on iPad 1
Summary: WebClient locks up under load on iPad 1
Status: RESOLVED FIXED
Alias: None
Product: iOS
Classification: Xamarin
Component: General ()
Version: 4.x
Hardware: Macintosh Mac OS
: High major
Target Milestone: 6.4.x (post async)
Assignee: Rolf Bjarne Kvinge [MSFT]
URL:
Depends on:
Blocks:
 
Reported: 2011-08-29 11:49 UTC by ric3kg
Modified: 2013-07-15 09:45 UTC (History)
7 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description ric3kg 2011-08-29 11:49:01 UTC
The following code locks up/freezes when run on iPad 1 with heavy download load. The thread just stops responding and 5 minutes later throws timeout error. Server logs indicate the device stops sending requests.

public void GetFile(string fileName, string url)
		{
			try
			{
				Timer timer = new Timer(SafetyValve);
				WriteLog("GetFile: "+fileName+" at url: "+url);
				Console.WriteLine("GetFile: "+fileName+" at url: "+url);
	
		       	WebClient wc = new WebClient();
                Uri uri = new Uri(url);
				timer.Change (0, 500); // Trigger it now and every 500ms
                byte[] bytes = wc.DownloadData(uri);
				timer.Change (Timeout.Infinite, Timeout.Infinite);
				
				string path = Path.Combine(tmpPath, fileName);
                
                File.WriteAllBytes(path, bytes);
                wc.Dispose();
				
			}
			catch(Exception ex)
			{
				Console.WriteLine("Error in GetFile "+ex.ToString());
				WriteLog("Error in GetFile "+ex.ToString());
			}
		}

static void SafetyValve(object state)
		{
			//Do nothing
//			Console.WriteLine("SafetyValve fired");
		}

Compiled with MT 4.0.6.
Comment 1 Gonzalo Paniagua Javier 2011-08-29 14:00:16 UTC
To whoever takes care of this bug: the 'Timer' related code in this sample is a workaround for the threadpool bug I fixed. My guess is that once the fix is released this problem will go away, but I can't test this.
Comment 2 Miguel de Icaza [MSFT] 2011-08-29 19:21:14 UTC
What version of MonoTouch are you using? 

We release an update that fixes this problem.
Comment 3 ric3kg 2011-08-29 19:24:50 UTC
4.0.6
Comment 4 René Ruppert 2011-12-12 18:27:26 UTC
Has this bug been reintroduced? I'm experiencing problems with large downloads in 5.0.1. It gets stuck on the device and times out.  It worked in later MT 4 versions.
I would like to try the timer workaround, but how exactly does it work?
Comment 5 René Ruppert 2012-01-23 03:35:08 UTC
The project attached to this bug: http://bugzilla.xamarin.com/show_bug.cgi?id=2843 has a full test case for the FaultException.
Comment 6 Miguel de Icaza [MSFT] 2012-01-23 16:00:16 UTC
Rolf would you mind taking a look a tthis?
Comment 7 Rolf Bjarne Kvinge [MSFT] 2012-01-30 09:23:09 UTC
René: are your comment #4 for this bug or for bug #2859?

And for this bug, are you downloading data just like the original bug reporter (WebClient.DownloadData), or are you using some other methods?
Comment 8 René Ruppert 2012-01-30 09:37:04 UTC
My comment 4 here is for this bug. Comment 5 however does not make a lot of sense. This should not be here and belongs to bug 2859. I copied it there.
Comment 9 Rolf Bjarne Kvinge [MSFT] 2012-02-01 05:52:13 UTC
René: are you downloading data just like the original bug reporter (WebClient.DownloadData), or are you using some other methods?
Comment 10 René Ruppert 2012-02-01 06:07:49 UTC
I am using Webservices 2.0 (SOAP) with an async call to download Base64 encoded XML.
Comment 12 PJ 2013-07-09 03:03:30 UTC
Hi ric3kg, Rene, it looks like you answered all the questions way back when for this bug - sorry we never got to the bottom of it. We're cleaning things up a bit
and at this point we might need an update. 

It looks like there was a fix from Gonzalo back in comment 1 that has been released since. Have you been able to reproduce in any recent MonoTouch (Xamarin.iOS) build?

In the interest of bugzilla sanity,
if we can't make forward progress here I will end up marking it as resolved
during the next release cycle.

Moving milestone to 6.4.x
Comment 13 René Ruppert 2013-07-15 07:02:13 UTC
To my knowledge, this issue has been resolved long ago.
Comment 14 Rolf Bjarne Kvinge [MSFT] 2013-07-15 09:45:32 UTC
Closing this then. Feel free to reopen if it still occurs.