/**
* 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;
}
}