Question

我正在尝试创建一个生成随机财务数据的后台线程。它使用childMOC和blockandwait进行插入和保存。它通常可以工作但偶尔崩溃，尤其是更大的数据集。我猜这可能是因为内存分配/释放问题？

对我做错了什么的想法？

主要背景声明

lazy var managedObjectContext: NSManagedObjectContext? = {
let coordinator = self.persistentStoreCoordinator
if coordinator == nil {
    return nil
}
var managedObjectContext = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
managedObjectContext.persistentStoreCoordinator = coordinator
return managedObjectContext }

获取MainMOC的副本并创建用于后台编写的PrivateMOC

let mainMOC = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext let privateMOC = NSManagedObjectContext(concurrencyType: .PrivateQueueConcurrencyType) privateMOC.parentContext = mainMOC

调用线程的主要功能

iDataManager.setupManager()
iDataManager.preloadDatabase()
//3. load data from coreData
iDataManager.loadListing()

//TODO: swap in load code
let loaderQueue = dispatch_queue_create("com.invest.serial.queue", DISPATCH_QUEUE_SERIAL)

dispatch_async(loaderQueue, {
    //does not account for the market listing
    for var index = 0; index < self.iDataManager.dmStockListings.count; ++index {
        self.iDataManager.preloadPrice(index)

        dispatch_async(dispatch_get_main_queue(), {
            self.loadingViewController.updateProgressIndicator(index, total: self.iDataManager.dmStockListings.count)
        })

    }
    dispatch_async(dispatch_get_main_queue(), {
        self.loadingViewController.progressLabel.text = "Loading Done!"
        self.iDataManager.saveChanges()

        //5. init viewControllers as Panels
        AppSettings().delay(0.2, closure: {
            self.setupViewControllers()
        })
     })
})

生成价格并调用privateMOC块

    let currentStock : MOStockListing
        currentStock = dmStockListings[index]

//声明为var dmStockListings：[MOStockListing] = []并包含mainContext中的所有MOStockListing

var error : NSError?
var stockPrices : [MOPrice] = []
var price : MOPrice

//check coredata if there are prices
var fetchRequest = NSFetchRequest(entityName: "MOPrice")
let sortDescriptor = NSSortDescriptor(key: "priceDate", ascending: true)
fetchRequest.sortDescriptors = [sortDescriptor]

let predicate = NSPredicate(format: "stock == %@", currentStock)
fetchRequest.predicate = predicate

stockPrices = privateMOC?.executeFetchRequest(fetchRequest, error: &error) as! [MOPrice]

if stockPrices.count == 0 {
    //create daily, weekly and monthly
    //set flag for update
    dmDatabaseState = .UpdateFlag

    privateMOC.performBlockAndWait({

        self.generateDemoPrices(currentStock)

        var errorPointer = NSErrorPointer()
        self.privateMOC.save(errorPointer)

    })

}

生成价格函数：迭代1000天以创建随机值。也在mainMOC中插入。一般都有效。但是我应该使用privateMoc吗？

            //load prices
        price = NSEntityDescription.insertNewObjectForEntityForName("MOPrice", inManagedObjectContext: privateMOC!) as! MOPrice

        price.setValue(close, forKey: "priceClose")
        price.setValue(high, forKey: "priceHigh")
        price.setValue(open, forKey: "priceOpen")
        price.setValue(low, forKey: "priceLow")
        price.setValue(volume, forKey: "priceVolume")
        price.setValue(dateValue, forKey: "priceDate")
        price.setValue(change, forKey: "priceChange")

        price.stock = currentStock

评论：我想我需要让privateMOC自己加载所有实体并执行插入然后调用保存。作为mainMOC的孩子，我不需要进行任何上下文合并，这是正确的吗？

编辑：这似乎有效。我还发现在主线程上保留额外的处理使加载时间更快。我使用privateMOC.blockandwait只写入coredata。我修改了上面的代码以反映这一点。

GCD和childcontext的Coredata并发无效访问/无法访问CDSnapshot_Entity

0 个答案: