ableegoldman commented on a change in pull request #9039: URL: https://github.com/apache/kafka/pull/9039#discussion_r465380753
########## File path: streams/src/test/java/org/apache/kafka/streams/integration/KStreamAggregationIntegrationTest.java ########## @@ -459,6 +460,95 @@ public void shouldGroupByKey() throws Exception { ))); } + + + @Test + public void shouldReduceSlidingWindows() throws Exception { + streamsConfiguration.put(StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, 0); + final long firstBatchTimestamp = 2000L; + final long timeDifference = 1000L; + produceMessages(firstBatchTimestamp); + final long secondBatchTimestamp = firstBatchTimestamp + timeDifference / 2; + produceMessages(secondBatchTimestamp); + final long thirdBatchTimestamp = secondBatchTimestamp + timeDifference - 100L; + produceMessages(thirdBatchTimestamp); Review comment: Just to clarify, we don't get any additional output when the stream time is advanced and older windows drop out of the grace period. We've already forwarded their final state when the last record to update that window was processed ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org