I actually thought that this has been improved (not fixed ;)) some time ago. My mistake. Thanks for the update and checking again.
On 19 Jun 2015, at 13:47, Fabian Hueske <fhue...@gmail.com> wrote: > This is not a bug. Chained combiners are not supported for ReduceFunctions > yet. :-( > I updated the JIRA accordingly. > > 2015-06-19 13:04 GMT+02:00 Ufuk Celebi <u...@apache.org>: > >> Hey all, >> >> on the current master running the WordCount example with a text file >> input/output results and a manual reduce function (instead of the sum(1)) >> results in a combiner, which is not chained. >> >> The corresponding issue is here: >> https://issues.apache.org/jira/browse/FLINK-2246 >> >> Can someone please confirm this? If it is an issue, we should fix it soon. >> The serialization overhead is noticeable on larger inputs. >> >> – Ufuk
