Re: correct pattern for using setOutputValueGroupingComparator?

[Owen O'Malley]

This is exactly what the setOutputValueGroupingComparator is for. Take  
a look at HADOOP-4545, for an example using the secondary sort. If you  
are using trunk or 0.20, look at src/examples/org/apache/hadoop/ 
examples/SecondarySort.java. The checked in example uses the new map/ 
reduce api that was introduced in 0.20.

-- Owen