对于在当前显示的iphone tableview中更新数据的长时间运行操作，最佳做法是什么？

Background:

I have a tableview displaying about 8 sections each backed with my own PlaceList class representing a list of objects (the implementation uses an NSMutableArray). There are around 200 objects in total. Each section corresponds to how far away the object is from the current location (e.g. within 1 mile, within 10, 25, 50...etc).I have a tableview displaying abo