WWW memory leak (iOS)?

I noticed in issue using the latest version of Unity. One of our applications is WWW heavy and it had started to crash when I upgraded it from a previous version. I noticed it was getting a lot more memory warnings and that memory use was actually increasing over time. If I had a guess, it'd be around the time that WWW on iOS was generated with the project.

So, given code snipped below:

Code (csharp):

1.    
2.     IEnumerator Start()
3.     {
4.         while(true)
5.         {
6.             Debug.Log("Start DL");
7.             WWW www = new WWW("http://www.dhxmedia.com/images/banners/shows/banner_03.jpg");
8.             {
9.                 yield return www;
10.             }
11.             www.Dispose();
12.             yield return new WaitForSeconds(1.0f);
13.             Debug.Log("Finish DL");
14.         }
15.     }
16.  

- Expected behaviour: run indefinitely. Downloading the image every 1 second.
- Actual behaviour: Runs out of memory, doesn't seem to clean itself up.

Sample project is posted at https://github.com/dhxmedia/WWWCrash

Allocation screenshot at https://github.com/dhxmedia/WWWCrash/blob/master/ios-4.3.4f1.png

In addition, memory tracking on Android seems to have the expected behaviour and does not run out.

 

Didn't 4.3.3 pull the WWW implementation out into the trampoline code? I suspect something different is now happening in code that you have access to.

 

You're right, this is something that we can fix in the generated Objective-C code, and that will suffice as an interim solution. However, I must stress the importance of this bug: if it is reproducable it will likely affect a large number of developers when updating apps that use WWW. Please run the tests that I have attached. A leak in WWW is a pretty big deal.

 

Pretty big deal indeed. Has this bug been confirmed yet?

 

This is likely the nail in the coffin for my company's use of Unity. Not that a bug exists. Bugs always exist. But a known massive memory leak (*) going unfixed for over 3 months. Not okay.

ps.
I still can't load a .wav with WWW then play it on iOS, can I? This got fixed for Android at some point.

 

In Unity 5.0.1f1, the error still exists. When www ends, it doesn't release the memory in iOS and the solution from Alexey doesn't work due to iOS ARC.

 

Issue is present in Unity 5.0.1p1 too.

This is a pretty serious issue. Could someone from Unity chime in?

The cleanup method is being called, and is correctly setting data to nil. I'm gonna have a prod and see if I can find what is holding the memory...

 

For a bug that takes < 15 lines of code to reproduce, you want us to upload an entire test project?

Also, we mentioned the version number in our posts. Same bug = same thread.

Don't fob us off!

 

What I mean is, <15 lines is the minimum required to reproduce the bug.

A Unity project, including those lines of code, is the absolute maximum required.

Good support usually requires your users to do the minimum required.

I'm sorting out a project now, give me a min.

Literally typed this and theres a fire down our street.... gonna be a few mins lol

 

Ok, so just spent a bit of time testing this to find the issue.

The memory leak is actually when you use www.assetBundle

Code (CSharp):

1.     IEnumerator RunTest()
2.     {
3.         print ("Starting download...");
4.         WWW www = new WWW("http://INSERTLARGEASSETBUNDLEURLHERE");
5.         yield return www;
6.  
7.         var assetBundle = www.assetBundle;
8.         var names = assetBundle.GetAllAssetNames();
9.  
10.         print ("Download finished");
11.         www.Dispose();
12.  
13.         assetBundle.Unload(true);
14.     }

Startup: memory floating around 15MB

Button press 1: memory goes to 23-25MB. Never comes back down to 15MB.

All subsequent presses: Memory jumps by size of downloaded file, then reduces down to 24.6 again.

So not as large an issue as we first thought, but we are still losing 8-10MB for no reason. I have no idea if the memory lost is tied to the size of the asset. I can't really spend more time debugging this. Especially as a fix seems out of my hands.

Bug No.:
695581

 

Your probably not wrong.

I'm actually having some un-related memory issues with asset-bundles in my real use-case that are making it hard to properly isolate the above issue.

Totally unrelated but creating a prefab uses very little memory, however. Loading an asset bundle from file, creating the prefab, then calling assetBundle.Unload(false) is causing S*** loads of memory to just hang around. I can even switch scenes and it's still there. I'm talking 20MB + each time. I'll probably end up creating a separate thread for this as I haven't really isolated it yet...

 

Issue also exists on the later versions of Unity 4.

My Bug No: 689768

I originally thought it was a leak when writing to disk as I assumed the general WWW leak was still fixed.

Here is my post (some other good links in there): http://forum.unity3d.com/threads/writing-www-bytes-to-disk-leaks-memory-on-ios.320248/

Hope that helps!

 

I am having this issue as well. The memory steadily climbs as more www calls are made, and putting more memory pressure just crashes the app as it runs out of memory.

 

So, do you guys have the solution? Any patch?

 

What I ended up doing at the time (and still is my solution..) was to switch to BestHTTP. You get better control over requests.

 

I do some test on ios. I find that when there is a network error(example: st ios to Flight mode), memory leak about 300k every request. When the network is ok, it doesn't leak some much. but the memory still keep growing up.... anyone can help?

 

Older thread here, if someone runs into this issue though for me the fix was in WWWConnection.mm the

-(void)cleanup{}

call. Add

_data = null;

to the end of it and the data seems to be releasing memory properly on dispose. I've only looked into this a little though so if it's creating other side effects please do post them here so others and myself know.

 

Thank you!! Been trying for the last 6 days to figure out a memory spike that was crashing low end devices (and only showing up in Xcode not Unity profiler), and this fixed it.

(btw on recent versions of Swift it looks like you need to use
_data = nil;
instead of 'null')

Thanks again for posting this

 

This memory leaking issue is reproducing in 5.4.5p5.(Both of www and unitywebrequest have same issue) I downgrade unity to 5.4.2p3 and it has been solved.