Drupal cron queue is very useful while running a big cron job. It will split a big cron job into small chunks and execute without getting timed out or being abruptly ended.
Three important things to remember in queue implementations are
- Create cron queue in hook_cron_queue_info
- Fill the queue with data
- Define worker callback function
STEP 1 - Create cron queue in hook_cron_queue_info