Refreshing is work only when i did several refresh

Question

I’m building an application for iPhone on iOS 7. In the application i fetched accelerometer data, extract features and saved the results as “records”.I have a record database that listed on tableview with another tab. The problem is refreshing the tableview.

After the measure data i tap the list tab and refreshing the tableview but nothing happens. Refreshing is only work when i did several refresh. First i think it’s about saving the data but it’s not. After the getting data if i tapped the list tab first time, all records listed on table view.It works. But If i tapped the tab earlier and i want to see the new record with refreshing, i have to refresh several times. Here is my refresh code:

 -(IBAction)refresh{
   [self.refreshControl beginRefreshing];

    dispatch_queue_t fetchQ = dispatch_queue_create("Reload", NULL);
    dispatch_async(fetchQ, ^{


        [self getRecordsFromDate];
        [self.date.managedObjectContext performBlock:^{

            dispatch_async(dispatch_get_main_queue(), ^{
                              [self.refreshControl endRefreshing];
            });
        }];
    });
}