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https://issues.apache.org/jira/browse/SAMZA-552?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yi Pan (Data Infrastructure) updated SAMZA-552:
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Attachment: DESIGN-SAMZA-552-6.pdf
DESIGN-SAMZA-552-6.md
Adding updated design doc. Highlights:
1. Fully adopt MillWheel model to allow multiple updates to the window outputs
2. Separated the design between the window usage in aggregation and join
3. Added more data structure/data store design details
> Tuple or time window semantics in physical operator
> ---------------------------------------------------
>
> Key: SAMZA-552
> URL: https://issues.apache.org/jira/browse/SAMZA-552
> Project: Samza
> Issue Type: Sub-task
> Components: sql
> Affects Versions: 0.9.0
> Reporter: Yi Pan (Data Infrastructure)
> Assignee: Yi Pan (Data Infrastructure)
> Attachments: DESIGN-SAMZA-552-3.md, DESIGN-SAMZA-552-3.pdf,
> DESIGN-SAMZA-552-6.md, DESIGN-SAMZA-552-6.pdf
>
>
> The discussion is based on how to support tuple and/or time based window
> operators in Samza physical operator layer.
> Here are the few observations:
> # Tuple represents the “physical ordering” of events while time-based window
> has semantic meanings to users
> # Total ordering between tuples are possible within Samza/Kafka given a
> deterministic MessageSelector on all input streams and offsets within each
> stream
> # No matter whether tuple or time is used to measure the window size, the
> window termination condition is needed to close a window to avoid the job to
> be wedged forever
> The following questions have to be answered to fully implement a window
> operator:
> # how to determine that a window is closed and no new tuples will be added?
> ## For tuple based, how do we close the window if messages do not come or get
> delayed?
> ## For time based, how do we close the window if
> ### the messages are not strictly in order w/ the time?
> ### the message w/ timestamp greater than the window boundary does not come
> or gets delayed?
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