Do timestamps and watermarks exist after window evaluation?

[Derek VerLee]

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?

[Aljoscha Krettek]

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

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

Best,

Aljoscha

On 8. Nov 2017, at 18:54, Derek VerLee <[hidden email]> 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?

[Derek VerLee]

This new documentation seems to answer my question directly.  It's good to know my intuitions where not wildly off.  Also thank you for continuing to improve the already good documentation.

Funny enough, some of the other questions I have, where also asked by other users in the last couple days, so I'll just reply on those threads if necessary.

Thanks!

On 11/9/17 9:32 AM, Aljoscha Krettek wrote:

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

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

Best,

Aljoscha

On 8. Nov 2017, at 18:54, Derek VerLee <[hidden email]> 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?