Hi Matt, What version of Flink are you using? The incremental agregation with fold(ACC, FoldFunction, WindowFunction) in a new change that will be part of Flink 1.2, for Flink 1.1 the correct way to perform incrementation aggregations is : apply(ACC, FoldFunction, WindowFunction) (see the docs for 1.1 [1])
[1] : https://ci.apache.org/projects/flink/flink-docs-release-1.1/apis/streaming/windows.html#windowfunction-with-incremental-aggregation Best, Yassine 2016-12-12 15:37 GMT+01:00 Chesnay Schepler <ches...@apache.org>: > Hello Matt, > > This looks like a bug in the fold() function to me. > > I'm adding Timo to the discussion, he can probably shed some light on this. > > Regards, > Chesnay > > > On 12.12.2016 15:13, Matt wrote: > > In case this is important, if I remove the WindowFunction, and only use > the FoldFunction it works fine. > > I don't see what is wrong... > > On Mon, Dec 12, 2016 at 10:53 AM, Matt <dromitl...@gmail.com> wrote: > >> Hi, >> >> I'm following the documentation [1] of window functions with incremental >> aggregations, but I'm getting an "input mismatch" error. >> >> The code [2] is almost identical to the one in the documentation, at the >> bottom you can find the exact error. >> >> What am I missing? Can you provide a working example of a fold function >> with both a FoldFunction and a WindowFunction? >> >> Regards, >> Matt >> >> [1] https://ci.apache.org/projects/flink/flink-docs-master/dev/ >> windows.html#windowfunction-with-incremental-aggregation >> >> [2] https://gist.github.com/cc7ed5570e4ce30c3a482ab835e3983d >> > > >
