ahuang98 commented on PR #17139: URL: https://github.com/apache/kafka/pull/17139#issuecomment-2590913611
> Complete the poll at t=30 Call measure at t=31. > We now have 20 ms of polling time inside an 11 ms measurement window. This causes the metric to [report 1.0](https://github.com/apache/kafka/blob/da0c3beffa96944a899ea949a7ab5705f67be882/raft/src/main/java/org/apache/kafka/raft/internals/TimeRatio.java#L59) and reset the counters to 0. This doesn't seem to be correct - it's quite convoluted but the measurement window (lastRecordedTimestampMs - intervalStartTimestampMs) would encompass the start of that poll. `testRatioMisalignedWindow` seems to do this check, I also wrote out a more detailed test to confirm my own understanding - ``` @Test public void testPartialPoll() { MetricConfig config = new MetricConfig(); MockTime time = new MockTime(); TimeRatio ratio = new TimeRatio(1.0); ratio.record(config, 0.0, time.milliseconds()); time.sleep(20); ratio.record(config, 10, time.milliseconds()); time.sleep(10); // pretend a poll() starts at this point time.sleep(10); // We ignore the last 20ms that lapsed after the last record() was called. Cumulative value captured by calls // to record since last call to measure is 10, lastRecordedTimestampMs - intervalStartTimestampMs = 20s - 0s. assertEquals(0.5, ratio.measure(config, time.milliseconds())); // Now the current poll() finishes. ratio.record(config, 10, time.milliseconds()); // Cumulative value captured by calls to record since last call to measure is 10, // lastRecordedTimestampMs - intervalStartTimestampMs = 40s - 20s. assertEquals(0.5, ratio.measure(config, time.milliseconds())); // If we had calculated the ratio over the entire window of the test (40s), the ratio would have been // (10 + 10) / 40 = 0.5. } ``` -- 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. To unsubscribe, e-mail: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
