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..9b04450 --- /dev/null +++ hbase-server/src/test/java/org/apache/hadoop/hbase/metrics/TestMetricsHistogram.java @@ -0,0 +1,117 @@ +/** + * 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 java.util.Arrays; +import java.util.Random; + +import org.apache.hadoop.hbase.metrics.histogram.MetricsHistogram; +import org.apache.hadoop.hbase.SmallTests; +import org.apache.hadoop.metrics.MetricsRecord; +import com.yammer.metrics.stats.Snapshot; +import org.junit.Assert; +import org.junit.Test; +import org.junit.experimental.categories.Category; +import static org.mockito.Mockito.*; + +@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()); + } + + private static int safeIndex(int i, int len) { + if (i < len && i >= 0) { + return i; + } else if (i >= len) { + return len - 1; + } else { + return 0; + } + } + + @Test + public void testRandom() { + final Random r = new Random(); + final MetricsHistogram h = new MetricsHistogram("testHistogram", null); + + final long[] data = new long[1000]; + + for (int i = 0; i < data.length; i++) { + data[i] = (long) (r.nextGaussian() * 10000.0); + h.update(data[i]); + } + + final Snapshot s = h.getSnapshot(); + Arrays.sort(data); + + // as long as the histogram chooses an item with index N+/-slop, accept it + final int slop = 20; + + // make sure the median, 75th percentile and 95th percentile are good + final int medianIndex = data.length / 2; + final long minAcceptableMedian = data[safeIndex(medianIndex - slop, + data.length)]; + final long maxAcceptableMedian = data[safeIndex(medianIndex + slop, + data.length)]; + Assert.assertTrue(s.getMedian() >= minAcceptableMedian + && s.getMedian() <= maxAcceptableMedian); + + final int seventyFifthIndex = (int) (data.length * 0.75); + final long minAcceptableseventyFifth = data[safeIndex(seventyFifthIndex + - slop, data.length)]; + final long maxAcceptableseventyFifth = data[safeIndex(seventyFifthIndex + + slop, data.length)]; + Assert.assertTrue(s.get75thPercentile() >= minAcceptableseventyFifth + && s.get75thPercentile() <= maxAcceptableseventyFifth); + + final int ninetyFifthIndex = (int) (data.length * 0.95); + final long minAcceptableninetyFifth = data[safeIndex(ninetyFifthIndex + - slop, data.length)]; + final long maxAcceptableninetyFifth = data[safeIndex(ninetyFifthIndex + + slop, data.length)]; + Assert.assertTrue(s.get95thPercentile() >= minAcceptableninetyFifth + && s.get95thPercentile() <= maxAcceptableninetyFifth); + // test the method pushMetric + MetricsRecord mr= mock(MetricsRecord.class); + h.pushMetric(mr); + verify(mr).setMetric("testHistogram_num_ops",1000L); + 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()); + + + } + +}