NSURLSession memory leak

Question

Even after invalidate a NSURLSession, running a profile using Instruments, some classes (probably privates) called TubeManager, HTTPConnectionCache and HTTPConnectionCacheDi

Answer 1

So, what is the question? Do you want to turn off caching? Network responses are routinely cached in NSURLCache in both memory and persistent storage.

If this cache usage is problematic, change the requestCachePolicy for the session configuration accordingly. Or change the cachePolicy of a NSMutableURLRequest, itself. You can also configure the maximum size of the URLCache that the session configuration uses, to constrain both the amount of RAM usage as well as the amount of persistent memory usage.

Even if you turn off caching, as a general rule one should not be surprised that API calls increase memory consumption, through no fault of your own. It's not uncommon for an app to experience some modest memory consumption the first time it performs some task. But one should not see the same growth in subsequent iterations while the app runs. When tracking memory usage, it's generally advisable to repeat the task multiple times and see if the app returns back to some steady state (which is desirable), or whether it continues to grow (which requires further investigation to make sure your code is not the source of the problem). But we rarely worry about the initial memory consumption unless it is dramatic.

Looking at your code snippet, there's nothing obviously wrong. I'd be inclined to suspect routine memory consumption by iOS. Assuming the issue is broader than the general cache behavior, if the memory consumption is dramatic and/or continues to grow each time the app performs this code, then provide more details and we can help you diagnose this further.

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This is what my memory profile looks like after four batches of 100 requests each; plus a final flag after I issued a memory warning:

(Note, that's a composite image so I could show you memory before the first batch, before the third batch, after the last batch and after I manually posted the memory warning. I combined these together to make it easier to see what the total allocations were at those four points in time.)