ios - 后台线程方法无法解决卡住问题

Question

我遇到了应用冻结的问题，因此我使用Instruments来发现问题，并发现问题与CoreData保存和提取有关。我尝试了后台coredata方法(父级，子级，通知)，但我的问题尚未解决。我也提到了http://martiancraft.com/blog/2015/03/core-data-stack/，但不知道该方法在我的应用程序中是如何实现的。

仪器日志:
https://www.dropbox.com/s/agjtw1wqubsgwew/Instruments9.trace.zip?dl=0

保存到数据库

  -(void)updateThreadEntityWithSyncDetails:(NSMutableDictionary *)inDictionary
  {

 NSString *loginUser=[[NSUserDefaults standardUserDefaults] valueForKey:@"currentUser"];

 AppDelegate *sharedDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
NSManagedObjectContext *context = [sharedDelegate managedObjectContext];

  //    NSManagedObjectContext *writerContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
  //   [writerContext setPersistentStoreCoordinator:[sharedDelegate persistentStoreCoordinator]];

 // create main thread MOC
//    context = [[NSManagedObjectContext alloc]        initWithConcurrencyType:NSMainQueueConcurrencyType];
    //    context.parentContext = writerContext;

   // NSManagedObjectContext *contextforThread = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];

  // contextforThread.parentContext = context;

 // [contextforThread performBlock:^{




NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setReturnsObjectsAsFaults:NO];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"ThreadInfo"
                                          inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSPredicate *userPredicate = [NSPredicate predicateWithFormat:@"userEmail == %@",loginUser];
NSPredicate *threadPredicate = [NSPredicate predicateWithFormat:@"threadID == %@",[inDictionary valueForKey:@"thread"]];
NSPredicate *compoundPredicate = [NSCompoundPredicate andPredicateWithSubpredicates: @[userPredicate, threadPredicate]];
[fetchRequest setPredicate:compoundPredicate];

NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:nil];
for (ThreadInfo *threadInfo in fetchedObjects)
{
    if([[inDictionary allKeys] containsObject:@"userEmail"])
    {
        if([inDictionary valueForKey:@"userEmail"]!=[NSNull null])
        {
            threadInfo.userEmail=[inDictionary valueForKey:@"userEmail"];
        }
    }
    if([[inDictionary allKeys] containsObject:@"badgeValue"])
    {
        if([inDictionary valueForKey:@"badgeValue"]!=[NSNull null])
        {
            threadInfo.badgeValue=[inDictionary valueForKey:@"badgeValue"];
        }
    }


    if([[inDictionary allKeys] containsObject:@"choice4Percentage"])
    {
        if([inDictionary valueForKey:@"choice4Percentage"]!=[NSNull null])
        {
            threadInfo.choice4Percentage=[inDictionary valueForKey:@"choice4Percentage"];
        }
    }
    if([[inDictionary allKeys] containsObject:@"choice5Percentage"])
    {
        if([inDictionary valueForKey:@"choice5Percentage"]!=[NSNull null])
        {
            threadInfo.choice5Percentage=[inDictionary valueForKey:@"choice5Percentage"];
        }
    }

 }

    NSError *error;
    if(![context save:&error]) {
        NSLog(@"Child error : %@",error);

    }

   // [context performBlock:^{
   //     NSError *error;
   //     if(![context save:&error]) {
   //         NSLog(@"%@",error);
   //     }
   //            }];
   // }];


 }    

FETCH

-(ThreadInfo *)retrieveSolicitationInfoForThreadID:(NSString*)inThreadID;
 {
NSString *loginUser=[[NSUserDefaults standardUserDefaults] valueForKey:@"currentUser"];

AppDelegate *sharedDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
NSManagedObjectContext *context = [sharedDelegate managedObjectContext];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setReturnsObjectsAsFaults:NO];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"ThreadInfo"
                                          inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSPredicate *userPredicate = [NSPredicate predicateWithFormat:@"userEmail == %@",loginUser];
NSPredicate *threadPredicate = [NSPredicate predicateWithFormat:@"threadID == %@",inThreadID];
\
NSPredicate *compoundPredicate = [NSCompoundPredicate andPredicateWithSubpredicates: @[userPredicate, threadPredicate]];

[fetchRequest setPredicate:compoundPredicate];

NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:nil];
if(fetchedObjects.count!=0)
{
    ThreadInfo *threadInfo=[fetchedObjects objectAtIndex:0];
    return threadInfo;
}
return nil;
}  

同步

-(void)updateSolicitationWithSyncDetails:(NSDictionary *)inDictionary
 {    
NSMutableDictionary *paramDict=[NSMutableDictionary dictionaryWithDictionary:inDictionary];
NSString *userEmail=[[NSUserDefaults standardUserDefaults] valueForKey:@"currentUser"];

[paramDict setObject:[NSNumber numberWithBool:NO] forKey:@"isSystemMessage"];
[paramDict setObject:userEmail forKey:@"userEmail"];

if([[inDictionary allKeys] containsObject:@"owned"])
{
   BOOL isDuplicate=[[IXDataBaseManager sharedNetworkDataManager] checkForExistenceOfThreadDetailsForSolicitationID:[inDictionary objectForKey:@"solicitation"]];// FETCH
    if(!isDuplicate)
    {
        int randomIndex=[[IXNetworkDataManager sharedNetworkDataManager] getIndexForColorImageForTab:@"OUT"];
        [paramDict setObject:message forKey:@"threadDescription"];
        [paramDict setObject:[NSNumber numberWithInt:randomIndex] forKey:@"colorCode"];

     BOOL isDuplicateVal=[[IXDataBaseManager sharedNetworkDataManager] checkForExistenceOfSolicitationID:[inDictionary objectForKey:@"solicitation"]];// FETCH
   [paramDict setObject:message forKey:@"threadDescription"];

  ThreadInfo *threadInfo=[[IXDataBaseManager sharedNetworkDataManager] retrieveSolicitationInfoForThreadID:[inDictionary objectForKey:@"solicitation"]];
  [paramDict setObject:threadInfo.threadID forKey:@"thread"];
  [[IXDataBaseManager sharedNetworkDataManager] updateThreadEntityWithSyncDetails:paramDict];
    }
}
}

Answer 1

首先，感谢您立即提供了代码片段和跟踪。那很有帮助。

因此，查看跟踪和代码。
-updateThreadEntityWithSyncDetails:在主线程上被调用，占该时间的33％。不好。

您正在通过nil传递error: 从来没有这样做。始终传递错误指针，并检查调用结果以查看是否存在错误。

这个条件可以使工作更加清洁:

if([[inDictionary allKeys] containsObject:@"userEmail"])
{
    if([inDictionary valueForKey:@"userEmail"]!=[NSNull null])
    {
        threadInfo.userEmail=[inDictionary valueForKey:@"userEmail"];
    }
}

考虑:

if (inDictionary[@"userEmail"] != nil && inDictionary[@"userEmail"] != [NSNull null]) {
    threadInfo.userEmail = inDictionary[@"userEmail"];
}

更容易阅读。

这种方法的重新编写将使工作脱离主线程:

- (void)updateThreadEntityWithSyncDetails:(NSMutableDictionary*)inDictionary
{
    NSString *loginUser = [[NSUserDefaults standardUserDefaults] valueForKey:@"currentUser"];

    AppDelegate *sharedDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];

    NSManagedObjectContext *context = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
    [context setParentContext:[sharedDelegate managedObjectContext]];

    [context performBlock:^{
        NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"ThreadInfo"];
        [fetchRequest setReturnsObjectsAsFaults:NO];
        [fetchRequest setPredicate:[NSPredicate predicateWithFormat:@"userEmail == %@ && threadID == %@",loginUser, inDictionary[@"thread"]];

        NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:nil];
        for (ThreadInfo *threadInfo in fetchedObjects) {
            if (inDictionary[@"userEmail"] != nil && inDictionary[@"userEmail"] != [NSNull null]) {
                threadInfo.userEmail = inDictionary[@"userEmail"];
            }
            if (inDictionary[@"badgeValue"] != nil && inDictionary[@"badgeValue"] != [NSNull null]) {
                threadInfo.badgeValue = inDictionary[@"badgeValue"];
            }
            if (inDictionary[@"choice4Percentage"] != nil && inDictionary[@"choice4Percentage"] != [NSNull null]) {
                threadInfo.choice4Percentage = inDictionary[@"choice4Percentage"];
            }
            if (inDictionary[@"choice5Percentage"] != nil && inDictionary[@"choice5Percentage"] != [NSNull null]) {
                threadInfo.choice5Percentage = inDictionary[@"choice5Percentage"];
            }
        }

        NSError *error = nil;
        if (![context save:&error]) {
            NSLog(@"Child error : %@",error);

        }
    }];
}

但仍可能会阻塞主线程，因为我猜测大部分CPU时间都在执行此访存中。提取速度很慢。您在该提取中有两个字符串比较。那是不好的，应该纠正。如果ThreadID不是字符串，则取反。否则，这只是糟糕的数据模型设计，除了修复该提取操作之外，不会有太多帮助。

您的另一个真正慢点是 -checkForExistenceOfThreadDetailsForThreadID:。您没有发布该方法，但我怀疑这是相同的问题，您的提取要花费大量的时间，并且它在主队列中。

总体而言，这的设计很差，需要重新设计。您正在比较数据存储中的字符串，这是检索数据的最慢方法之一。您也位于主线程上，可以处理不需要在主线程上出现的事情。

记住黄金法则，如果用户未操纵数据，则操纵绝不能在主队列上。没有异常(exception)。