Observer reference is not released on unsubscribe

[fdoyle]

With the following code
http://pastebin.com/VUZ5aApe
and using the latest version of rxjava (0.18.4),

rotations should result in the activity calling unsubscribe on my subscription.

This should release the reference to my observer, which should in turn release the reference to my activity.

However, the memory tests I've done show that as I rotate the phone, my activity count keeps going up, which means the reference to my activity is not being released.

(let me know if the pastebin expires for some reason, I'll get something back up)

[benjchristensen]

Can someone who has worked with Android and the AndroidScheduler take a look at this please?

[zsxwing]

This should release the reference to my observer, which should in turn release the reference to my activity.

Thread.sleep(10000); will block the Observable so that unsubscribe can not release the reference to the observer at once. Did the number of activity decrease after a few seconds?

[fdoyle]

I changed it to Thread.sleep(500) and even after a few minutes, the activity count did not go down.

[zsxwing]

@fdoyle, just another question, How do you monitor the activity count? Even if an activity has no reference, it may still in memory if GC does not free its memory. Can you force a GC and then check it again?

[fdoyle]

I'm monitoring the activity count with
adb shell dumpsys meminfo com.lacronicus.rxjavaleaktest.app

And after forcing a GC on the process with android debug monitor, the activity count remains high (10+ after as many rotations)

[fdoyle]

Has anyone else been able to confirm that this is an issue? I'm worried about using rxjava in any of my projects until this is resolved.

[benjchristensen]

Anyone that works on Android able to comment on this?

[devisnik]

Seems your long-running task never finishes?

[zsxwing]

@fdoyle, sorry that I forgot this one.

In your code, the anonymous Subscriber will hold the Activity reference. Because your long-running task never finishes, the Subscriber will always be used and never be released. Finally, neither the Subscriber or the Activity object can be recycled.

[evant]

I feel that calling unsubscribe() not clearing the reference to the Subscription until the task finishes is non-obvious and could bite a lot of people working on Android. Is there a reason for this design decision? Is there a way to rewrite the example so that the Activity is not leaked while the task is running?

[dpsm]

@fdoyle @evant AndroidObservable.fromActivity(..) should avoid leaking your Activity.

[devisnik]

@evant Just don't bind your activity to the subscription, which is done through the inner class in the example.

[evant]

@dpsm Do you mean AndroidObservable.bindActivity()? fromActivity() is deprecated.

[devisnik]

@dpsm From the javadoc of AndroidObservable.fromActivity():
"Currently, this is equivalent to calling observeOn(AndroidSchedulers.mainThread()), but this behavior may change in the future, so it is encouraged to use this wrapper instead."

So I guess not.

[dpsm]

@evant @devisnik I meant AndroidObservable.bindActivity(..)

"This helper will schedule the given sequence to be observed on the main UI thread and ensure
* that no notifications will be forwarded to the activity in case it is scheduled to finish."