A long-running Parse operation is being executed on the main thread

Question

I am getting the error:

\"A long-running Parse operation is being executed on the main thread. Break on warnParseOperationOnMainThread() to debug.\"

Answer 1

For me this happened when I called:

[[PFUser currentUser] refresh];

The solution was to replace it with:

[[PFUser currentUser] refreshInBackgroundWithBlock:nil];

See also this answer on the Parse Help site.

Answer 2

This is a gentle warning to the developers when they make the Parse calls that would block the main thread.

This is where you can see it all happen,, add a symbolic breakpoint on warnBlockingOperationOnMainThread only if you use a Parse API released from 2015+. Otherwise, put it on the warnParseOperationOnMainThread.

It'll break on that function while you are running your code, and will show you a stack trace which should help you to find the blocking function.

See the images below to have a better understanding.

Answer 3

It Almost happens with all Parse queries or data saving. It avoid this, there is option to perform operation in background. Actually there are two alternatives, one is to perform in background and other is perform in background with block of code.

Answer 4

Maybe it is a bit late, but here you go. I think the problem come from the fact that you are trying to get to objects fetch at the same time:

[[PFUser currentUser] objectId];

and:

 [query getObjectInBackgroundWithId...];

It will be better to get the userId first, such as:

//First fetch and store the id in a string so you can reuse it whenever you want
NSString *userId = [PFUser currentUser].objectId; 

Second:

  // Do your second fetch here:          
  PFQuery *query = [PFQuery queryWithClassName:@"User"];        

 [query getObjectInBackgroundWithId:userId block:^(PFObject *object, NSError *error) {

 self.firstName = object[@"firstname"];
 self.lastName = object[@"lastname"];

 self.nameLabel.text = [[NSArray arrayWithObjects:self.firstName, self.lastName, nil]    componentsJoinedByString:@" "];
 }];

Et voila!