Re: flink eventTime, lateness, maxoutoforderness

Posted by Eron Wright on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/flink-eventTime-lateness-maxoutoforderness-tp17318p17319.html

Take a look at the section of Flink documentation titled "Event Time and Watermarks":

https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/event_time.html#event-time-and-watermarks

Also read the excellent series "Streaming 101" and "102", has useful animations depicting the flow of time:

https://www.oreilly.com/ideas/the-world-beyond-batch-streaming-101

https://www.oreilly.com/ideas/the-world-beyond-batch-streaming-102

Think of the watermark as a clock, ticking along due to information from the connector or from a watermark generator. 

Hope this helps,

Eron 

On Sat, Dec 16, 2017 at 8:07 AM, chen <[hidden email]> wrote:

eventTime, lateness,  maxoutoforderness are all about time.
event Time is the water mark time on the record.
lateness is record time or the real word time?
maxoutoforderness is record time or the real word time?

dataStream.keyBy(row -> (String)row.getField(0))
        .window(TumblingEventTimeWindows.of(Time.seconds(5)))
         .allowedLateness(Time.seconds(5))
         .fold(initRow(), new MyFoldFunction())

public Watermark getCurrentWatermark() {
        return new Watermark(currentTime - 5000);}

Does anyone could explain the time of eventTime,lateness,maxoutoforderness?



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