PFObject.pinAllIBackground使用了很多内存

Question

我需要从MyClass 100 000行下载，我使用这个功能，但我不明白 PFObject.pinAllIBackground使用了很多内存。

func downloadData(code:String, skip: Int, limit: Int ){
    let download = PFQuery(className: «MyClass»)
    download.limit = limit
    download.skip = skip
    download.findObjectsInBackgroundWithBlock(){ (objects: [PFObject]?, error: NSError?) -> Void in
        if error == nil {
            PFObject.pinAllInBackground(objects, block: {(success:Bool, error: NSError?) -> Void in
                if error == nil{
                    if objects!.count == limit {
                        let newskip = skip + limit
                        print("Page - \(newskip)")
                        self.downloadData(code, skip: newskip, limit: limit)
                    }
                }
            })
        }
    }
}

Memory Use