On Wed, Feb 22, 2017 at 11:19 AM, Till Rohrmann <trohrm...@apache.org> wrote: > In general, you’re right Lin Li that we don’t honour the Iterable contract > which should allow you to create an arbitrary number of iterators over the > data. Honestly, I’m not sure why we did this change because it’s not very > intuitive. Maybe Ufuk can chime in because he opened FLINK-1023.
The discussion in the issue is pretty detailed. The best summary is probably found in the PR description https://github.com/apache/flink/pull/84: "This patch allows the GroupReduce and the CoGroup to use the beautiful foreach loop syntax." Orignally, the PR ensured that a TraversableOnceException was thrown.
