删除对象的多对多关系非常慢，如何让它更快？

Question

使用https://github.com/magicalpanda/MagicalRecord

的CoreData操作

我有2个表，

1. 播放列表，列：播放列表名称
2. 曲目，专栏：专辑，艺术家，创作时...... ......

播放列表和曲目是多对多关系，删除规则是Nullify。

有两种情况：

1. NSFetchedResultsController for [self MR_fetchAllSortedBy:@"CreateTime" ascending:NO withPredicate:nil groupBy:nil delegate:self inContext:context]; ...... Tracks *obj = [self.fetchedResultsController objectAtIndexPath:indexPath]; [obj MR_deleteEntity]; [[obj managedObjectContext] MR_saveToPersistentStoreAndWait];

快速删除跟踪对象。

1. [self MR_fetchAllGroupedBy:@"Album" withPredicate:nil sortedBy:nil ascending:NO delegate:self inContext:context]; ......

   的NSFetchedResultsController

   segue push

id<NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:indexPath.row]; AlbumTracksViewController *albumTracksvc = segue.destinationViewController; albumTracksvc.tracks =[NSMutableArray arrayWithArray:[sectionInfo objects]]; albumTracksvc.title = [sectionInfo name];

In AlbumTracksViewController：

Tracks *obj = [self.tracks objectAtIndexPath:indexPath]; [obj MR_deleteEntity]; [[obj managedObjectContext] MR_saveToPersistentStoreAndWait];

the delete Track Object very slow.

我该怎么做才能解决删除缓慢的问题？