It have 4 stages you dont need all of them: - getInputData(context) (here you do a search with the things you need) - map(context) (here you apply conditions to that search if you need to...) - reduce(context) (Here the script used key/value that got from map) - summarize(summary) (Once here is done...) Second and third stages work as iterator(loops) base on each result coming from first Stage...