diff --git hbase-server/src/test/java/org/apache/hadoop/hbase/metrics/TestMetricsHistogram.java hbase-server/src/test/java/org/apache/hadoop/hbase/metrics/TestMetricsHistogram.java new file mode 100644 index 0000000..0d853fa --- /dev/null +++ hbase-server/src/test/java/org/apache/hadoop/hbase/metrics/TestMetricsHistogram.java @@ -0,0 +1,112 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.hadoop.hbase.metrics; + +import static org.mockito.Matchers.anyFloat; +import static org.mockito.Matchers.anyLong; +import static org.mockito.Matchers.eq; +import static org.mockito.Mockito.mock; +import static org.mockito.Mockito.verify; + +import java.util.Random; + +import org.apache.hadoop.hbase.SmallTests; +import org.apache.hadoop.hbase.metrics.histogram.MetricsHistogram; +import org.apache.hadoop.metrics.MetricsRecord; +import org.junit.Assert; +import org.junit.Test; +import org.junit.experimental.categories.Category; + +import com.yammer.metrics.stats.Snapshot; + +@SuppressWarnings("deprecation") +@Category(SmallTests.class) +public class TestMetricsHistogram { + + @Test + public void testBasicUniform() { + MetricsHistogram h = new MetricsHistogram("testHistogram", null); + + for (int i = 0; i < 100; i++) { + h.update(i); + } + + Assert.assertEquals(100, h.getCount()); + Assert.assertEquals(0, h.getMin()); + Assert.assertEquals(99, h.getMax()); + Assert.assertEquals(49.5d, h.getMean(), 0.01); + } + + @Test + public void testSnapshotPercentiles() { + final MetricsHistogram h = new MetricsHistogram("testHistogram", null); + final long[] data = genRandomData(h); + + final Snapshot s = h.getSnapshot(); + + assertPercentile(data, 50, s.getMedian()); + assertPercentile(data, 75, s.get75thPercentile()); + assertPercentile(data, 95, s.get95thPercentile()); + assertPercentile(data, 98, s.get98thPercentile()); + assertPercentile(data, 99, s.get99thPercentile()); + assertPercentile(data, 99.9, s.get999thPercentile()); + } + + @Test + public void testPushMetric() { + final MetricsHistogram h = new MetricsHistogram("testHistogram", null); + genRandomData(h); + + MetricsRecord mr = mock(MetricsRecord.class); + h.pushMetric(mr); + + verify(mr).setMetric("testHistogram_num_ops", 10000L); + verify(mr).setMetric(eq("testHistogram_min"), anyLong()); + verify(mr).setMetric(eq("testHistogram_max"), anyLong()); + verify(mr).setMetric(eq("testHistogram_mean"), anyFloat()); + verify(mr).setMetric(eq("testHistogram_std_dev"), anyFloat()); + verify(mr).setMetric(eq("testHistogram_median"), anyFloat()); + verify(mr).setMetric(eq("testHistogram_75th_percentile"), anyFloat()); + verify(mr).setMetric(eq("testHistogram_95th_percentile"), anyFloat()); + verify(mr).setMetric(eq("testHistogram_99th_percentile"), anyFloat()); + } + + private void assertPercentile(long[] data, double percentile, double value) { + int count = 0; + for (long v : data) { + if (v < value) { + count++; + } + } + Assert.assertEquals("Wrong " + percentile + " percentile", + (int)(percentile / 100), count / data.length); + } + + private long[] genRandomData(final MetricsHistogram h) { + final Random r = new Random(); + final long[] data = new long[10000]; + + for (int i = 0; i < data.length; i++) { + data[i] = (long) (r.nextGaussian() * 10000); + h.update(data[i]); + } + + return data; + } + +}