I build a parsing algorithm using NSXMLParser.
Im having doubt as to what is the best strategy for keeping my memory usage on a minimum.
I have a valueObject (e.g. "Person") this object has ≈ 30 NSString properties, while parsing the xml I continually alloc and release a temporary Person object as the nodes are traversed.
I checked this and there is only one of these Person objects instantiated at any time.
When a node is traversed and a Person is "build" I pass the Person to a NSMutableArray and release this Person. Seems no problem there. (I'll need the array for a tableView).
When I reach around 50+ Person objects in the array my app just quits, didReceiveMemoryWarning doesn't get called, no other warnings, no parseErrorOccurred, nothing?
If I limit the number of Persons in xml the app does just fine, I haven't been able to find any memory leaks with Instruments.
I think that I simply can't hold 50+ Person objects in an array… seems a bit harsh, but I haven't got much memory experience with the iPhone, so this is just a guess.
The xml is search results from which the user probably only needs a few, so persisting them to my core model to keep them around for display seems a bit crazy.
What would be a good strategy for keeping these Person objects around? or am I missing a huge memory leak since the iPhone should be able to handle much more than this?
Hope some experienced developers can point me in the right direction:)
Thank you!
Best Answer
How long are those strings? Generally, on the iPhone 3G and older models, your app should have a minimum of about 20 MB of memory available (much more on the 3Gs). This is no absolute rule, of course, but a decent rule of thumb. To occupy this much memory with 50 objects would mean ~400-500 KB per Person object. Is this in the ballpark? If so, you will probably need a memory management strategy that does not keep all objects in memory at the same time. Core Data can probably help you a great deal in that case.