Laravel Long-polling显示数据的机会

Question

My long-polling seems not working sometimes. Sometimes it shows the newest data let's say 2 out of 10 submitted text to database.

$db = $this->post->getLatest($userIds);//Get the 1 newest data from` database. 
    $oras = date('H:i:s', $time()); //Set the time format
      foreach($db as $tl)
       {
        $dbTime = date('H:i:s', strtotime($tl->created_at)); //Setting the time format.
        if($dbTime == $oras)
          {
           return $tl->post." -----> ".$oras."<br />"; //Showing the newest data
          }
       else
          {
            usleep(5000); // sleep in milliseconds
          }
      }