nsfetchedresultscontroller

I have two tables with the following structure MainCategory: name position hasSubCategories SubCategory: name position display belongsToMainCategory Now I want to display all subcategories (where display attribute = YES) grouped by main category. The main category sections should be sorted as defined by position and the subcategories itself (within the section) by their position attribute. (name by the way can be the same for a certain main category...my tables have more attributes but they aren't relevant to understand the problem). But my order is completely messed up. Why? Here's my code

In the model, I have two entities: Record and Category. Category is one-to-many with Record through inverse relationship. The persistent store is of SQLITE type and the db is not so small, about 23MB (17k records). I use a list-detail design to show the records table and the detailed record view.The list viewController uses NSFetchedResultsController. Building on the device, if I don't use setFetchBatchSize: CoreData: annotation: sql connection fetch time: 15.8800s CoreData: annotation: total fetch execution time: 16.9198s for 17028 rows. OMG! If I use setFetchBatchSize:25, everything works