Raw comparators are not generated for types that are generated with the Hadoop record framework. This could have a substantial performance impact when using hadoop record generated types in Map/Reduce. The record i/o framework should auto-generate raw comparators for types.
Comparison for hadoop record i/o types is defined to be member wise comparison of objects. A possible implementation could only deserialize one member from each object at a time, compare them and either return or move on to the next member if the values are equal.