My app may create / delete thousands of managed objects while running. I have used secondary NSManagedObjectContexts(MOCs) with NSPrivateQueueConcurrencyType and NSOperations to make the app more responsive and most parts work well. But when I pressed ⌘Q and if the number of unsaved objects are large, the app hangs for quite a while before the window closes (the beach ball keeps on rotating...).
How to make the window disappear immediately, before the save of the MOC?
I tried to insert window.close() in applicationShouldTerminate in the AppDelegate, but it has no effect.
My code for deletion is nothing special, except the hierachy is really large. Something like
let items = self.items as! Set<Item>
Group.removeItems(items)
for i in items {
self.managedObjectContext?.deleteObject(i)
}
Item is a hierarchic entity. Group has a one-to-many relationship to items.
The removeItems is generated by CoreData with @NSManaged.
Many thanks.
Updates
I tried the following code, the save still blocks the UI.
@IBAction func quit(sender: AnyObject) {
NSRunningApplication.currentApplication().hide()
NSApp.terminate(sender)
}
func applicationShouldTerminate(sender: NSApplication) -> NSApplicationTerminateReply
{
let op = NSBlockOperation { () -> Void in
do {
try self.managedObjectContext.save()
} catch {
print("error")
}
NSOperationQueue.mainQueue().addOperationWithBlock({ () -> Void in
NSApp.replyToApplicationShouldTerminate(true)
})
}
op.start()
return .TerminateLater
}
This doesn't make the window close first, when the amount of created / deleted managed objects is large.
Then I changed to the following, as suggested by @bteapot. Still has no effect. The window still won't close immediately.
@IBAction func quit(sender: AnyObject) {
NSRunningApplication.currentApplication().hide()
NSApp.terminate(sender)
}
func applicationShouldTerminate(sender: NSApplication) -> NSApplicationTerminateReply {
let op = NSBlockOperation { () -> Void in
self.managedObjectContext.performBlock({ () -> Void in
do {
try self.managedObjectContext.save()
} catch {
print("errr")
}
})
NSOperationQueue.mainQueue().addOperationWithBlock({ () -> Void in
NSApp.replyToApplicationShouldTerminate(true)
})
}
dispatch_async ( dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),
{() -> Void in
op.start()
})
return .TerminateLater
}
Finally I sort of solved the problem, though the UI is still blocked sometimes, even with the same test data.
The approach used can be found here: https://blog.codecentric.de/en/2014/11/concurrency-coredata/ , Core Data background context best practice , https://www.cocoanetics.com/2012/07/multi-context-coredata/
First I made a backgroundMOC with .PrivateQueueConcurrencyType
lazy var backgroundMOC : NSManagedObjectContext = {
let coordinator = self.persistentStoreCoordinator
let moc = NSManagedObjectContext(concurrencyType: .PrivateQueueConcurrencyType)
moc.persistentStoreCoordinator = coordinator
moc.undoManager = nil
return moc
}()
Then made it prent of the original moc.
lazy var managedObjectContext: NSManagedObjectContext = {
var managedObjectContext = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
// managedObjectContext.persistentStoreCoordinator = coordinator
managedObjectContext.parentContext = self.backgroundMOC
managedObjectContext.undoManager = nil
return managedObjectContext
}()
Two methods for the save.
func saveBackgroundMOC() {
self.backgroundMOC.performBlock { () -> Void in
do {
try self.backgroundMOC.save()
NSApp.replyToApplicationShouldTerminate(true)
} catch {
print("save error: bg")
}
}
}
func saveMainMOC() {
self.managedObjectContext.performBlock { () -> Void in
do {
try self.managedObjectContext.save()
self.saveBackgroundMOC()
} catch {
print("save error")
}
}
}
Change the applicationShouldTerminate() to
func applicationShouldTerminate(sender: NSApplication) -> NSApplicationTerminateReply {
if !managedObjectContext.commitEditing() {
NSLog("\(NSStringFromClass(self.dynamicType)) unable to commit editing to terminate")
return .TerminateCancel
}
if !managedObjectContext.hasChanges {
return .TerminateNow
}
saveMainMOC()
return .TerminateLater
}
The reason it was so slow was I was using NSXMLStoreType instead of NSSQLiteStoreType.
