Core Data Memory Crash [closed] - ios

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I am using Core Data for the first time in my project and I feel there is a serious problem in my approach. What I am doing is that I fetch data from server (data includes pngs as well). Save it in core data locally. Then at app launch, I load the entire data in an array. Then this array is used where ever I need it. I think I am following a very bad approach. Can anyone guide me what should be a better approach? Should I only query Core Data when data is needed instead of loading everything in memory at start?
When data is being populated to the array, I can see memory increasing in Xcode and after a certain value, it crashes.
Here is my code for saving data:
func saveDataLocally () {
let moContext = ((UIApplication.shared.delegate) as! AppDelegate).managedObjectContext
let entity = NSEntityDescription.entity(forEntityName: "FoodPlace", in: moContext)
for foodPlaceData in self.downloadedData_ {
let foodPlace = NSManagedObject(entity: entity!, insertInto: moContext) as! FoodPlace
foodPlace.objectId = foodPlaceData.objectId_
foodPlace.name = foodPlaceData.name_
foodPlace.address = foodPlaceData.address_
foodPlace.keywords = foodPlaceData.keywords_
foodPlace.baseFavourites = Int64(foodPlaceData.baseFavourites_)
foodPlace.startingTime = foodPlaceData.startingTime_
foodPlace.endingTime = foodPlaceData.endingTime_
foodPlace.category = foodPlaceData.category_
foodPlace.basePrice = foodPlaceData.basePrice_
foodPlace.dealTitle = foodPlaceData.dealTitle_
foodPlace.versionNumber = Int64(foodPlaceData.versionNumber_)
foodPlace.menuItems = NSKeyedArchiver.archivedData(withRootObject: foodPlaceData.menuItems_)
foodPlace.location = NSKeyedArchiver.archivedData(withRootObject: foodPlaceData.location_)
foodPlace.deals = NSKeyedArchiver.archivedData(withRootObject: foodPlaceData.deals_)
foodPlace.foodPlacePhotos = NSKeyedArchiver.archivedData(withRootObject: foodPlaceData.foodPlacePhotos_)
moContext.insert(foodPlace)
}
do {
try moContext.save()
}
catch let error {
print("error saving = \(error.localizedDescription)")
}
}
where menuItems is a Dictionary which contains text as well as png images. Also, deals and foodPlacePhotos only contain png images.
Here is the code for fetching:
func loadDataLocally () {
let moContext = ((UIApplication.shared.delegate) as! AppDelegate).managedObjectContext
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "FoodPlace")
do {
let results = try moContext.fetch(request)
let savedFoodPlaceData = results as! [FoodPlace]
downloadedData_ = []
for foodPlace in savedFoodPlaceData {
let objectId = foodPlace.objectId
let name = foodPlace.name
let address = foodPlace.address
let keywords = foodPlace.keywords
let baseFavourites = foodPlace.baseFavourites
let startingTime = foodPlace.startingTime
let endingTime = foodPlace.endingTime
let category = foodPlace.category
let menuItems = NSKeyedUnarchiver.unarchiveObject(with: foodPlace.menuItems!) as? [Dictionary<String,AnyObject>]
let location = NSKeyedUnarchiver.unarchiveObject(with: foodPlace.location!) as? Dictionary<String,Double>
let deals = NSKeyedUnarchiver.unarchiveObject(with: foodPlace.deals!) as? [UIImage]
let basePrice = Float(foodPlace.basePrice)
let dealTitle = foodPlace.dealTitle
let versionNumber = foodPlace.versionNumber
let foodPlacePhotos = NSKeyedUnarchiver.unarchiveObject(with: foodPlace.foodPlacePhotos!) as? [UIImage]
let data = FoodPlaceData(objectId: objectId!, name: name!, address: address!, category: category!, keywords: keywords!, baseFavourites: Int(baseFavourites), startingTime: startingTime!, endingTime: endingTime!, menuItems: menuItems!, location: location!, deals: deals!,basePrice: basePrice,dealTitle: dealTitle!,versionNumber: Int(versionNumber),foodPlacePhotos: foodPlacePhotos!)
downloadedData_.insert(data, at: downloadedData_.count)
}
}
catch let error {
print("error fetching = \(error.localizedDescription)")
}
}
and here is the code for deleting data:
func deleteAllLocalData () {
let moContext = ((UIApplication.shared.delegate) as! AppDelegate).managedObjectContext
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "FoodPlace")
fetchRequest.returnsObjectsAsFaults = false
do {
let results = try moContext.fetch(fetchRequest)
for managedObject in results {
let managedObjectData : NSManagedObject = managedObject as! NSManagedObject
moContext.delete(managedObjectData)
}
try moContext.save()
} catch let error {
print("Delete all data in FoodPlace error : \(error) \((error as NSError).userInfo)")
}
}

Answer 1

Difficult to be prescriptive without a lot more detail about your code. But a few thoughts:
rather than storing the PNG data in CoreData itself, consider storing it in the file system directly, and using CoreData to store only the filename for the PNG.
Alternatively, if you really want the PNGs in CoreData, consider adding a separate entity for the PNG, and adding a one-one relationship from your current entity to the new one.
Either of the above will avoid all the PNG data being loaded into memory when you load the array. You can then load/unload the PNGs (either from the file system or from the related entity) as needed.
In addition, consider using:
NSFetchedResultsController and/or
fetchBatchSize
These will help to avoid all the objects being loaded into memory.