Core data disable journal_mode don't work - objective-c

Question

I want to disable the journal mode in my core data app.
This is the code:
- (NSPersistentContainer *)persistentContainer {
// The persistent container for the application. This implementation creates and returns a container, having loaded the store for the application to it.
#synchronized (self) {
if (_persistentContainer == nil) {
_persistentContainer = [[NSPersistentContainer alloc] initWithName:#"My_App"];
NSURL *url = [[self applicationFilesDirectory] URLByAppendingPathComponent:#"My_App.sqlite"];
NSPersistentStoreDescription *description=[[NSPersistentStoreDescription alloc]initWithURL:url];
NSMutableDictionary *pragmaOptions=[NSMutableDictionary dictionary];
[pragmaOptions setObject:#"DELETE" forKey:#"journal_mode"];
[description setOption:pragmaOptions forKey:#"NSQlitePragmaOptions"];
_persistentContainer.persistentStoreDescriptions=#[description];
[_persistentContainer loadPersistentStoresWithCompletionHandler:^(NSPersistentStoreDescription *storeDescription, NSError *error) {
if (error != nil) {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
NSLog(#"Unresolved error %#, %#", error, error.userInfo);
abort();
}
}];
}
}
return _persistentContainer;}
I also verified with this:
NSArray *descriptionArray=[_persistentContainer persistentStoreDescriptions];
NSPersistentStoreDescription * description=[descriptionArray objectAtIndex:0];
NSLog(#"%#",description.options);
and the result of NSLog is:
{
NSInferMappingModelAutomaticallyOption = 1;
NSMigratePersistentStoresAutomaticallyOption = 1;
NSQlitePragmaOptions = {
"journal_mode" = DELETE;
};
but when I restart my app I always find in the application directory all the three file My_App.sqlite, My_App.sqlite-shm and My_App.sqlite-wal.
Why doesn't it work?