apache/incubator-flink — pull request #207 by StephanEwen (2014-11-17 00:38:41+00:00)
Title: [FLINK-1237] Add support for custom partitioners

- Functions: GroupReduce, Reduce, Aggregate on UnsortedGrouping, SortedGrouping (Java API & Scala API)
- Manual partition on DataSet (Java API & Scala API)
- Distinct operations provide semantic properties for preservation of distinctified fields
- Tests for pushown (or not pushdown) of custom partitionings and forced rebalancing
- Tests for GlobalProperties matching of partitionings
- Caching of generated requested data properties for unary operators