Crossposting from stackoverflow <https://stackoverflow.com/questions/67591684/flink-1-12-2-all-events-getting-dropped-as-late>
My flink pipeline looks like below WatermarkStrategy<GenericMetricV2> watermarkStrategy = WatermarkStrategy .<GenericMetricV2>forBoundedOutOfOrderness(Duration.ofSeconds(900)) .withTimestampAssigner((metric, timestamp) -> { logger.info("ETS: mts: {}, ts: {}", metric.metricPoint.timeInstant, timestamp); return metric.metricPoint.timeInstant; }); metricStream = kafkasource .process(<>) .assignTimestampsAndWatermarks(watermarkStrategy) .transform("debugFilter", TypeInformation.of(<>), new StreamWatermarkDebugFilter<>("Op")) .filter(<>) .map(<>) .flatMap(<>) .keyBy(<>) .window(TumblingEventTimeWindows.of(Time.seconds(300))) .allowedLateneess(900) .sideOutputLateData(lateOutputTag) .aggregate(AggregateFunction, ProcessWindowFunction) .addSink() I am running with parallelism 1 and default setAutowatermarkInterval of 200 ms. I did not set setStreamTimeCharacteristic as from flink 1.12 by default it is event time. I am seeing that watermark is progressing from the output of StreamWatermarkDebugFilter <https://github.com/antonmry/flink-playground/blob/main/src/main/java/galiglobal/flink/eventTime/StreamWatermarkDebugFilter.java> but all the events are getting marked as late and is getting gathered at lateOutputTag. 2021-05-18 17:14:19,745 INFO - ETS: mts: 1621310100000, ts: 1621310582271 2021-05-18 17:14:19,745 INFO - ETS: mts: 1621310100000, ts: 1621310582271 2021-05-18 17:14:19,842 INFO StreamWatermarkDebugFilter - Op, Watermark: 1621309499999 2021-05-18 17:14:19,944 INFO - ETS: mts: 1621309800000, ts: 1621310582275 2021-05-18 17:14:19,944 INFO - ETS: mts: 1621309800000, ts: 1621310582275 ... 2021-05-18 17:14:20,107 INFO - ETS: mts: 1621310380000, ts: 1621310582278 2021-05-18 17:14:20,107 INFO - ETS: mts: 1621310380000, ts: 1621310582278 2021-05-18 17:14:20,137 INFO StreamWatermarkDebugFilter - Op, Watermark: 1621309779999 2021-05-18 17:14:20,203 INFO - ETS: mts: 1621309800000, ts: 1621310582279 ... 2021-05-18 17:17:47,839 INFO - ETS: mts: 1621310100000, ts: 1621310681159 2021-05-18 17:17:47,848 INFO StreamWatermarkDebugFilter - Op, Watermark: 1621310099999 2021-05-18 17:17:47,958 INFO - ETS: mts: 1621309800000, ts: 1621310681237 2021-05-18 17:17:47,958 INFO - ETS: mts: 1621309800000, ts: 1621310681237 ... 2021-05-18 17:22:24,207 INFO - ETS: mts: 1621310100000, ts: 1621310703622 2021-05-18 17:22:24,229 INFO StreamWatermarkDebugFilter - Op, Watermark: 1621310399999 2021-05-18 17:22:24,315 INFO - ETS: mts: 1621309800000, ts: 1621310705177 2021-05-18 17:22:24,315 INFO - ETS: mts: 1621309800000, ts: 1621310705177 I have seen this discussion <https://stackoverflow.com/questions/61020086/flink-window-function-getresult-not-fired> and it is not an idleness problem. It looks like related to this discussion <https://stackoverflow.com/questions/51399973/flink-time-window-based-on-event-time-output-nothing>. Can someone suggest how can I debug this problem further?