liveBook · Manning

Final windowed result

As explained in Kafka Streams in Action, Second Edition

A final windowed result is the result emitted for a time interval after its window has closed, with no subsequent updates for that interval.

A final windowed result is the single result emitted when a window closes. Unlike intermediate results, it receives no updates while the window remains open. section 9.3

Session aggregation

A page-view session aggregation can use a two-minute inactivity window, aggregate records, suppress updates until the session window closes, and publish the resulting session aggregate.

How Kafka Streams in Action, Second Edition covers it

How deep it goes
Distinguishes intermediate from final results and names EmitStrategy and suppression, while deferring stream-time mechanics.
Examples
Uses one-minute tumbling windows and two-minute page-view session aggregation to demonstrate emission and suppression.
What it assumes
Assumes windowed aggregation and groupByKey usage, while distinguishing closed-window results from ongoing updates.
What you can do after
Apply it via EmitStrategy.onWindowClose() or Suppressed.untilWindowCloses(...) to publish one result per closed window.
How it connects
Connects windowed aggregation with intermediate results, stream time, state stores, changelog topics, EmitStrategy, and suppression.
Cover of Kafka Streams in Action, Second Edition
liveBookmanning.com
Read Kafka Streams in Action, Second Edition on liveBook Get the book at manning.com

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Kafka Streams in Action, Second Edition. The section links point to the parts of the book it draws on.