Core Data and iOS 7: Different behavior of persistent store
Solution 1:
Yes, Apple have changed the default journal mode to WAL for iOS7. You can specify the journal mode by adding the NSSQLitePragmasOption to the options when calling addPersistentStoreWithType:configuration:url:options:error. E.g. to set the previous default mode of DELETE:
NSDictionary *options = @{ NSSQLitePragmasOption : @{@"journal_mode" : @"DELETE"} };
In my experience WAL gives better performance, but also see this post:
iOS CoreData - are there any disadvantages to enabling sqlite WAL / Write-Ahead Logging