Do timestamps and watermarks exist after window evaluation?

[Derek VerLee <de...@gmail.com>]

When composing ("chaining") multiple windowing operations on the same
stream are watermarks transmitted down stream after window evaluation,
and are the records emitted from WindowFunctions given timestamps? Do I
need to or should I always assignTimestampsAndWatermarks to the
outputsof window evaluations if I want to window again? If automatically
assigned, how should I think about them in an event time context? Would
the event time of a record resulting from a WindowFunction be the
window's end time in the case of a TimeWindow?

Re: Do timestamps and watermarks exist after window evaluation?

[Aljoscha Krettek <al...@apache.org>]

Hi,

This new section in the windowing documentation will help answer your question: https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/stream/operators/windows.html#working-with-window-results <https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/stream/operators/windows.html#working-with-window-results>

Please let me know if you have any further questions. :-)

Best,
Aljoscha

> On 8. Nov 2017, at 18:54, Derek VerLee <de...@gmail.com> wrote:
> 
> When composing ("chaining") multiple windowing operations on the same
> stream are watermarks transmitted down stream after window evaluation,
> and are the records emitted from WindowFunctions given timestamps? Do I
> need to or should I always assignTimestampsAndWatermarks to the
> outputsof window evaluations if I want to window again? If automatically
> assigned, how should I think about them in an event time context? Would
> the event time of a record resulting from a WindowFunction be the
> window's end time in the case of a TimeWindow?
>