Adobe Flex App page file usage going through the roof!

Question

I have been working on an Adobe Flex application for some months now, and the application is meant to run 24/7 for days (weeks!) continuously. However, I'm now seeing that after a few days of running nonstop the computer it runs on tells me that the system is low on virtual memory and gives me an error about Page File usage. Once I close the Flex app, the Page File usage goes down from 1.9 GB to 100 MB (or less). It seems that its using up all this memory and not freeing it although I have been very careful in my app to not keep huge arrays.

The app does some graphing and draws a lot of shapes (to greate a 'gauge') and then gets rid of them by re-declaring that object as another 'gauge'.

Any idea why my page file usage is climbing so high?!

Answer 1

You most probably have eventListeners that are not being removed. They keep references to objects and prevent them from being garbage collected.

Answer 2

You can use the profiler in Flex Builder professional to see where your memory usage is going. Like another poster mentioned, event listeners are alot of times the culprits in cases like this, but more generally, just because you think you are getting rid (destroying or deleting) a variable, doesn't mean that it is really getting taken care of by the garbage collector. If any reference (like an event listener) still exists to that variable (or object) it will not be collected. The profiler will point out these things.

Answer 3

I've heard rumors that putting anything on the Stage will create memory leaks. In other words, you can be as careful as possible with your code, but you'll still leak memory. This has not been validated by Adobe, as far as I know. A good test might be to instantiate a Shape and a Sprite and a MovieClip, add them to the display list, and then let the app run overnight. Would love to hear the results if you do end up testing this.