Fix negative mean latency metric Patch by Per Otterstrom; Reviewed by Chris Lohfink for CASSANDRA-12876
Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/7e05f393 Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/7e05f393 Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/7e05f393 Branch: refs/heads/trunk Commit: 7e05f393f39c90ec0447b1cc893ff46901ae3071 Parents: c884b70 Author: Per Otterstrom <per.otterst...@ericsson.com> Authored: Wed Jan 18 14:56:01 2017 +0100 Committer: Jeff Jirsa <j...@jeffjirsa.net> Committed: Sat Feb 11 23:28:35 2017 -0800 ---------------------------------------------------------------------- CHANGES.txt | 1 + .../DecayingEstimatedHistogramReservoir.java | 3 +- ...DecayingEstimatedHistogramReservoirTest.java | 31 ++++++++++++++++++++ 3 files changed, 34 insertions(+), 1 deletion(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/cassandra/blob/7e05f393/CHANGES.txt ---------------------------------------------------------------------- diff --git a/CHANGES.txt b/CHANGES.txt index fc79796..214fe97 100644 --- a/CHANGES.txt +++ b/CHANGES.txt @@ -1,4 +1,5 @@ 2.2.9 + * Fix negative mean latency metric (CASSANDRA-12876) * Use only one file pointer when creating commitlog segments (CASSANDRA-12539) * Fix speculative retry bugs (CASSANDRA-13009) * Fix handling of nulls and unsets in IN conditions (CASSANDRA-12981) http://git-wip-us.apache.org/repos/asf/cassandra/blob/7e05f393/src/java/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoir.java ---------------------------------------------------------------------- diff --git a/src/java/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoir.java b/src/java/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoir.java index 2458164..2f8bdf8 100644 --- a/src/java/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoir.java +++ b/src/java/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoir.java @@ -352,11 +352,12 @@ public class DecayingEstimatedHistogramReservoir implements Reservoir public EstimatedHistogramReservoirSnapshot(DecayingEstimatedHistogramReservoir reservoir) { final int length = reservoir.decayingBuckets.length(); + final double rescaleFactor = forwardDecayWeight(clock.getTime()); this.decayingBuckets = new long[length]; for (int i = 0; i < length; i++) - this.decayingBuckets[i] = reservoir.decayingBuckets.get(i); + this.decayingBuckets[i] = Math.round(reservoir.decayingBuckets.get(i) / rescaleFactor); } /** http://git-wip-us.apache.org/repos/asf/cassandra/blob/7e05f393/test/unit/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoirTest.java ---------------------------------------------------------------------- diff --git a/test/unit/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoirTest.java b/test/unit/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoirTest.java index f2d817f..ef1fed3 100644 --- a/test/unit/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoirTest.java +++ b/test/unit/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoirTest.java @@ -354,6 +354,32 @@ public class DecayingEstimatedHistogramReservoirTest } } + @Test + public void testDecayingMean() + { + { + TestClock clock = new TestClock(); + + DecayingEstimatedHistogramReservoir histogram = new DecayingEstimatedHistogramReservoir(DecayingEstimatedHistogramReservoir.DEFAULT_ZERO_CONSIDERATION, DecayingEstimatedHistogramReservoir.DEFAULT_BUCKET_COUNT, clock); + + clock.addMillis(DecayingEstimatedHistogramReservoir.LANDMARK_RESET_INTERVAL_IN_MS - 1_000L); + + while (clock.getTime() < DecayingEstimatedHistogramReservoir.LANDMARK_RESET_INTERVAL_IN_MS + 1_000L) + { + clock.addMillis(900); + for (int i = 0; i < 1_000_000; i++) + { + histogram.update(1000); + histogram.update(2000); + histogram.update(3000); + histogram.update(4000); + histogram.update(5000); + } + assertEquals(3000D, histogram.getSnapshot().getMean(), 500D); + } + } + } + private void assertEstimatedQuantile(long expectedValue, double actualValue) { assertTrue("Expected at least [" + expectedValue + "] but actual is [" + actualValue + "]", actualValue >= expectedValue); @@ -363,6 +389,11 @@ public class DecayingEstimatedHistogramReservoirTest public class TestClock extends Clock { private long tick = 0; + public void addMillis(long millis) + { + tick += millis * 1_000_000L; + } + public void addSeconds(long seconds) { tick += seconds * 1_000_000_000L;
