The Queue API in Drupal is designed to manage tasks.The queue system allows placing items in a queue and processing them later.The Queue API is a simple,reliable way to keep track huge lists of tasks without requiring you to know anything about the whole group.Prepare your data, put it in one item at a time, and take back one item at a time to process. When you are done with a single item, just report back that you have finished and the item is removed from the queue.