Hi Everyone, I am trying to implement Secondary Sort Algorithm on mydata. But I am having a trouble with my Combiner.
When I donot use Combiner, grouping is done well, I mean one reduce task is running for every pair, sharing the same first element. However, when I set Combiner as Reducer class itself, grouping in the Combiner is not done according to my custom GroupingComparator class though. How can i overrride Combiner class's grouping? Or, is there any diagram, showing the sequence of workflow(both in map phase, calls of mapper classes and calls of combiner classes and so on sequentially) in more detailed? Thanks very much.
