flink-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Tzu-Li (Gordon) Tai" <tzuli...@apache.org>
Subject Re: Flink 1.2 time window operation
Date Thu, 30 Mar 2017 11:09:17 GMT
Hi,

Thanks for the clarification.

What are the reasons behind consuming/producing messages from/to Kafka while the window has
not expired yet?
First, some remarks here -  sources (in your case the Kafka consumer) will not stop fetching
/ producing data when the windows haven’t fired yet. Does this explain what you have plotted
in the diagram you attached (sorry, I can’t really reason about the diagram because I’m
not so sure what the values of the x-y axes represent)?

If you’re writing the outputs of the window operation to Kafka (by adding a Kafka sink after
the windowing), then yes it should only write to Kafka when the window has fired. The characteristics will
also differ for different types of windows, so you should definitely take a look at the Windowing
docs [1] about them.

Cheers,
Gordon

[1] https://ci.apache.org/projects/flink/flink-docs-release-1.3/dev/windows.html#window-assigners
On March 30, 2017 at 2:37:41 PM, Dominik Safaric (dominiksafaric@gmail.com) wrote:

What are the reasons behind consuming/producing messages from/to Kafka while the window has
not expired yet?
Mime
View raw message