[英]CoreData concurrency and releasing objects
I'm currently validating our new CoreData architecture which is being used in a multi-threaded environment. 我目前正在验证新的CoreData体系结构,该体系结构已在多线程环境中使用。 For analyzing I'm using GDCoreDataConcurrencyDebugging which prints a warning, every time a ManagedObject is accessed from the wrong thread / queue (as far as I understood). 为了进行分析,我使用GDCoreDataConcurrencyDebugging打印警告,每次从错误的线程/队列访问ManagedObject时(据我所知)。
Now I'm getting tons of warnings like this: 现在我收到大量这样的警告:
Invalid concurrent access to managed object calling 'release'
I was able to put a break-point where the warning is generated and the code looks like this: 我能够在生成警告的地方放置一个断点,代码如下所示:
-(MyObject*) createMyObject {
return (MyObject*)[self insertNewObjectEntityWithName:@"MyObject"];
}
-(NSManagedObject*) insertNewObjectEntityWithName:(NSString*) entityName {
__block NSManagedObject *managedObject;
[self.managedObjectContext performBlockAndWait:^(void) {
managedObject = [NSEntityDescription insertNewObjectForEntityForName:entityName
inManagedObjectContext:self.managedObjectContext];
}];
return managedObject;
}
Its breaking in the createMyObject
-method after the return, which I guess is when the objects are being released. 返回之后,它打破了createMyObject
方法,我猜这是对象被释放的时间。 Is there anything special I missed with CoreData-concurrency and object-release? 我在CoreData并发性和对象释放方面有什么特别的错过吗? I've looked around and there isn't anything being mentioned about object-release, only about autoreleasepools which I'm not using. 我环顾四周,没有提到任何有关对象释放的内容,仅涉及到我没有使用的自动释放池。
You are performing the work in a performBlockAndWait:
call, which is correct. 您正在performBlockAndWait:
调用中执行工作,这是正确的。 However, you proceed to return the object, presumably from a different thread. 但是,您可能继续从其他线程返回对象。 That is not legal. 那是不合法的。 All managed objects must be accessed from the thread/queue on which they are created, with the exception of the objectID
property, which is always valid. 必须从创建对象的线程/队列访问所有托管对象,但objectID
属性始终有效。
plz use this code to get managedObjectContext .managed objects must be accessed from the thread/queue on which they are created. 请使用此代码获取managedObjectContext。必须从创建对象的线程/队列访问托管对象。
- (NSManagedObjectContext *)managedObjectContext
{
NSThread *thisThread = [NSThread currentThread];
if (thisThread == [NSThread mainThread])
{
if (_managedObjectContext != nil) {
return _managedObjectContext;
}
//
if ([self persistentStoreCoordinator] != nil) {
_managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
[_managedObjectContext setPersistentStoreCoordinator:[self persistentStoreCoordinator]];
}
[_managedObjectContext setRetainsRegisteredObjects:YES];
[_managedObjectContext setMergePolicy:NSMergeByPropertyObjectTrumpMergePolicy];
return _managedObjectContext;
}
else
{
//Return separate MOC for each new thread
NSManagedObjectContext *threadManagedObjectContext = [[thisThread threadDictionary] objectForKey:@"MOC_KEY"];
if (threadManagedObjectContext == nil)
{
threadManagedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
[threadManagedObjectContext setPersistentStoreCoordinator: coordinator];
[[thisThread threadDictionary] setObject:threadManagedObjectContext forKey:@"MOC_KEY"];
}
return threadManagedObjectContext;
}
}
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