NSURLConnection is growing in instruments, is this NSURLCache?

Question

So I have a memory problem with my app. The app has a MKMapView with MKOverlayRenderer which loads images on the map. Everything working ok but after 30-60 minutes the app crashes due memory.

With Instruments I found that NSURLConnection is growing and because I cannot find anything else (besides all kind of stuff I dont understand) I think thats is my problem.

Screenshot instruments after runnning for 1-2 minutes:

Screenshot instruments after running for 12-13 minutes:

Images are loaded like this in the canDrawMapRect method and saved to tmp folder (if I turn this off the NSURLConnection won't grow that high):

    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:url]];
    [NSURLConnection sendAsynchronousRequest:request
                                       queue:[OperationQueues sharedOperationQueue]
                           completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {


                               [data writeToFile:path atomically:YES];

Then loaded in the drawMapRect method.

I tried fixing this with the following code:

AppDelegate:

int cacheSizeMemory = 4*1024*1024; // 4MB
int cacheSizeDisk = 32*1024*1024; // 32MB
NSURLCache *sharedCache = [[NSURLCache alloc] initWithMemoryCapacity:cacheSizeMemory diskCapacity:cacheSizeDisk diskPath:@"nsurlcache"];
[NSURLCache setSharedURLCache:sharedCache];

NSURLCache *URLCache = [[NSURLCache alloc] initWithMemoryCapacity:cacheSizeMemory
                                                     diskCapacity:cacheSizeDisk
                                                         diskPath:nil];
[NSURLCache setSharedURLCache:URLCache];

ViewController:

- (void)didReceiveMemoryWarning
{
    [[NSURLCache sharedURLCache] removeAllCachedResponses];
    [super didReceiveMemoryWarning];
}

right after the request: [added]

[[NSURLCache sharedURLCache] removeCachedResponseForRequest:request];

But as you can see in Instruments without any luck.

1. Could this be my problem?
2. Is this the NSURLCache which is growing or something else?

As requested a couple more screenshots from instruments:

Answer 1

First, 400 network requests in one minute seems pretty excessive. Some of those requests are probably duplicated or unnecessary. The amount of calls is obviously downloading a lot of information, and not giving the os much time to cleanup.

Second, your NSURLCache is actually providing more memory space than the default cache. I tested on my device/simulator and ios provides a default memory capacity of 512 000 bytes. You're caches are initialized with 4 194 304 bytes (and way more on disk).

I would suggest that you set your cache size smaller to see some improvement. However, investigating the amount of network requests that are made will provide longer term benefits.