Hi, the error is related to the way you specify the grouping and the sorting key. The API is currently restricted in the way, that you can only use a key selector function for the sorting key if you also used a selector function for the grouping key.
In Scala the use of key selector functions is often not very obvious. If you post the groupBy().sortGroup() command and the input type, I can help you getting it right. Cheers, Fabian 2015-06-16 23:37 GMT+02:00 Michele Bertoni <michele1.bert...@mail.polimi.it> : > Hi everybody, > I am trying to sorting a grouped dataset, but i am getting this error: > > Exception in thread "main" > org.apache.flink.api.common.InvalidProgramException: Sorting on KeySelector > keys only works with KeySelector grouping. > at > org.apache.flink.api.scala.GroupedDataSet.sortGroup(GroupedDataSet.scala:113) > at > it.polimi.genomics.flink.FlinkImplementation.regionOperation.OrderRD$.sort(OrderRD.scala:82) > … > > can anybody help me understanding the error? > i have no idea what it means and google is not helpful in this case > > > thanks! > cheers > Michele
