How do I force a reducer in cascading?

Question

To gain some of the benefits only possible with reducers and not mappers.

Answer 1

Found my answer in Google Groups:

Use a GroupBy which invariable will use a reducer when performing the grouping:

previousPipe = new GroupBy(previousPipe); //this does a Group on Fields.All

Reducing Number of Files (another alternative with less coupling)

previousPipe = new GroupBy(previousPipe, new Fields("rand"), 
               new RandonNumGen(Fields.Args));

Where new RandonNumGen(Fields.Args) is a function you build from Function to create a new Fields("rand") that creates temporary random number (temporary meaning you drop the field later).

For more information check this Google Groups thread: