Merge branch 'cassandra-2.2' into cassandra-3.0

Jaumo · Feb 12, 2017 · 51e3660 · 51e3660
2 parents 8ec6090 + 7e05f39
commit 51e3660
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Showing 3 changed files with 34 additions and 1 deletion.
diff --git a/CHANGES.txt b/CHANGES.txt
@@ -37,6 +37,7 @@
  * Prevent reloading of logback.xml from UDF sandbox (CASSANDRA-12535)
  * Reenable HeapPool (CASSANDRA-12900)
 Merged from 2.2:
+ * 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)

diff --git a/src/java/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoir.java b/src/java/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoir.java
@@ -352,11 +352,12 @@ private class EstimatedHistogramReservoirSnapshot extends Snapshot
         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);
         }
 
         /**

diff --git a/test/unit/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoirTest.java b/test/unit/org/apache/cassandra/metrics/DecayingEstimatedHistogramReservoirTest.java
@@ -354,6 +354,32 @@ public void testDecayingPercentile()
         }
     }
 
+    @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 @@ private void assertEstimatedQuantile(long expectedValue, double actualValue)
     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;