CoreData內存開銷

任何人都可以解釋我如何最大限度地減少內存開銷在這個NSManagedObject子類CoreData內存開銷

- (void) saveImage:(UIImage*)image 
{ 
    assert(image != nil); 

    if (self.image == nil) 
    { 
     Image* image = [NSEntityDescription insertNewObjectForEntityForName:@"Image" 
                inManagedObjectContext:self.managedObjectContext]; 
     self.image = image; 
    } 

    self.image.imageData = UIImagePNGRepresentation(image); 
    self.image.saved = [NSNumber numberWithBool:NO]; 
    self.hasPicture = [NSNumber numberWithBool:YES]; 

    NSError* error = nil; 
    if (![self.managedObjectContext save:&error]) 
    { 
     MDLogForTag(@"CoreData", @"Saving image failed with error: %@",error); 
     assert(NO); 
    } 
    [self.managedObjectContext refreshObject:self mergeChanges:NO]; 
}

2小時活躍使用的應用程序後，UIImagePNGRepresentation(image)產生500MB。這是一個數據對象的生命週期

# Category Event Type RefCt Timestamp Address Size Responsible Library Responsible Caller 
0 NSConcreteMutableData Malloc 1 00:45.345.122 0x109dd6d0 32 Foundation +[NSData(NSData) data] 
1 NSConcreteMutableData Autorelease  00:45.345.126 0x109dd6d0 0 UIKit   UIImagePNGRepresentation 
2 NSConcreteMutableData Retain 2 00:45.345.133 0x109dd6d0 0 ImageIO   CGImageWriteSessionCreateWithMutableData 
3 NSConcreteMutableData Release 1 00:45.366.875 0x109dd6d0 0 UIKit   UIImagePNGRepresentation 
4 NSConcreteMutableData Retain 2 00:45.366.910 0x109dd6d0 0 MyProject -[Feature saveImage:] 
5 NSConcreteMutableData Retain 3 00:45.369.430 0x109dd6d0 0 CoreData -[NSSQLCore _populateRowForOp:withObject:] 
6 NSConcreteMutableData Retain 4 00:45.370.260 0x109dd6d0 0 CoreData -[NSSQLBindVariable setValue:] 
7 NSConcreteMutableData Release 3 00:45.370.648 0x109dd6d0 0 CoreData -[NSSQLBindVariable setValue:] 
8 NSConcreteMutableData Retain 4 00:45.376.359 0x109dd6d0 0 CoreData -[NSManagedObject(_NSInternalMethods) _newPropertiesForRetainedTypes:andCopiedTypes:preserveFaults:] 
9 NSConcreteMutableData Retain 5 00:45.376.668 0x109dd6d0 0 CoreData -[NSSQLRow copy] 
10 NSConcreteMutableData Release 4 00:45.426.906 0x109dd6d0 0 CoreData -[NSSQLOperation dealloc] 
11 NSConcreteMutableData Release 3 00:45.427.006 0x109dd6d0 0 CoreData -[NSKnownKeysDictionary1 dealloc] 
12 NSConcreteMutableData Release 2 00:45.427.131 0x109dd6d0 0 GraphicsServices GSEventRunModal

有時正確地釋放對象與此呼籲

# Category Event Type RefCt Timestamp Address Size Responsible Library Responsible Caller 
0 NSConcreteMutableData Malloc 1 87:35.960.485 0x1088ace0 32 Foundation +[NSData(NSData) data] 
1 NSConcreteMutableData Autorelease  87:35.960.489 0x1088ace0 0 UIKit UIImagePNGRepresentation 
2 NSConcreteMutableData Retain 2 87:35.960.496 0x1088ace0 0 ImageIO CGImageWriteSessionCreateWithMutableData 
3 NSConcreteMutableData Release 1 87:35.971.032 0x1088ace0 0 UIKit UIImagePNGRepresentation 
4 NSConcreteMutableData Retain 2 87:35.971.081 0x1088ace0 0 MyProject -[Feature saveThumbnail:] 
5 NSConcreteMutableData Retain 3 87:35.973.784 0x1088ace0 0 CoreData -[NSSQLCore _populateRowForOp:withObject:] 
6 NSConcreteMutableData Retain 4 87:35.999.687 0x1088ace0 0 CoreData -[NSSQLBindVariable setValue:] 
7 NSConcreteMutableData Release 3 87:36.000.023 0x1088ace0 0 CoreData -[NSSQLBindVariable setValue:] 
8 NSConcreteMutableData Retain 4 87:36.009.349 0x1088ace0 0 CoreData -[NSManagedObject(_NSInternalMethods) _newPropertiesForRetainedTypes:andCopiedTypes:preserveFaults:] 
9 NSConcreteMutableData Retain 5 87:36.009.758 0x1088ace0 0 CoreData -[NSSQLRow copy] 
10 NSConcreteMutableData Release 4 87:36.146.717 0x1088ace0 0 CoreData -[NSSQLOperation dealloc] 
11 NSConcreteMutableData Release 3 87:36.146.843 0x1088ace0 0 CoreData -[NSKnownKeysDictionary1 dealloc] 
12 NSConcreteMutableData Release 2 87:36.146.983 0x1088ace0 0 GraphicsServices GSEventRunModal 
13 NSConcreteMutableData Release 1 87:39.734.569 0x1088ace0 0 CoreData -[NSManagedObject(_NSInternalMethods) _clearRawPropertiesWithHint:] 
14 NSConcreteMutableData Release 0 87:39.734.577 0x1088ace0 0 CoreData -[NSSQLCore managedObjectContextDidUnregisterObjectsWithIDs:] 
15 NSConcreteMutableData Free 0 87:39.734.582 0x1088ace0 -32 Foundation -[NSConcreteMutableData dealloc]

來源

2011-09-13 DAloG

DALOG，

雖然這將是很好看的屬性列表，我相信self.image和self.image.imageData之間有一個保留循環。我想你應該在你的方法的末尾添加一行代碼：

[self.managedObjectContext refreshObject:self.image mergeChanges:NO]; 
[self.managedObjectContext refreshObject:self  mergeChanges:NO];

安德魯

來源

2011-09-14 04:02:56 adonoho

是。我的錯。退出此功能後，我會觸發.image屬性的錯誤。現在我是所有更改後的刷新對象。謝謝） – DAloG

CoreData內存開銷

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