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https://issues.apache.org/jira/browse/FLINK-12714?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Wenshuai Hou closed FLINK-12714.
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Resolution: Fixed
just saw this in flink doc.
For example, with an event-time-based windowing strategy that creates
non-overlapping (or tumbling) windows every 5 minutes and has an allowed
lateness of 1 min, Flink will create a new window for the interval between
{{12:00}} and {{12:05}} when the first element with a timestamp that falls into
this interval arrives, and it will remove it when the watermark passes the
{{12:06}} timestamp
> confusion about flink time window TimeWindow#getWindowStartWithOffset
> ---------------------------------------------------------------------
>
> Key: FLINK-12714
> URL: https://issues.apache.org/jira/browse/FLINK-12714
> Project: Flink
> Issue Type: Improvement
> Components: flink-contrib
> Affects Versions: 1.8.0
> Reporter: Wenshuai Hou
> Priority: Minor
>
>
> hi flink team, i think the flink doc on how time windows are created and the
> javadoc of related method is a little confusing. They give me the impression
> that the window-start equals to the timestamp of the first event assigned to
> that window, however the window-start is actually quantized by the
> windowSize, see links below. Is this the intention or is this a mistake? If
> it's intended, can we please leave a comment in flink doc somewhere to make
> this more clear? I spent 5 hours wondering why my flink tests fail until i
> find that method.
>
> Thanks
> Wen
>
> links:
> ================
>
> The flink doc from here :
> [https://ci.apache.org/projects/flink/flink-docs-stable/dev/stream/operators/windows.html#window-lifecycle]
>
> > In a nutshell, a window is *created* as soon as the first element that
> > should belong to this window arrives
>
> the java doc of this method:
> org.apache.flink.streaming.api.windowing.windows.TimeWindow#getWindowStartWithOffset
>
>
> {code:java}
> /**
> * Method to get the window start for a timestamp.
> *
> * @param timestamp epoch millisecond to get the window start.
> * @param offset The offset which window start would be shifted by.
> * @param windowSize The size of the generated windows.
> * @return window start
> */
> public static long getWindowStartWithOffset(long timestamp, long offset, long
> windowSize) {
> {code}
>
>
>
>
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