| /* |
| * 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.cassandra.utils; |
| |
| import org.junit.Test; |
| |
| import static org.junit.Assert.*; |
| |
| |
| public class EstimatedHistogramTest |
| { |
| @Test |
| public void testSimple() |
| { |
| { |
| // 0 and 1 map to the same, first bucket |
| EstimatedHistogram histogram = new EstimatedHistogram(); |
| histogram.add(0); |
| assertEquals(1, histogram.get(0)); |
| histogram.add(1); |
| assertEquals(2, histogram.get(0)); |
| } |
| { |
| // 0 and 1 map to different buckets |
| EstimatedHistogram histogram = new EstimatedHistogram(90, true); |
| histogram.add(0); |
| assertEquals(1, histogram.get(0)); |
| histogram.add(1); |
| assertEquals(1, histogram.get(0)); |
| assertEquals(1, histogram.get(1)); |
| } |
| } |
| |
| @Test |
| public void testOverflow() |
| { |
| EstimatedHistogram histogram = new EstimatedHistogram(1); |
| histogram.add(100); |
| assert histogram.isOverflowed(); |
| assertEquals(Long.MAX_VALUE, histogram.max()); |
| } |
| |
| @Test |
| public void testMinMax() |
| { |
| EstimatedHistogram histogram = new EstimatedHistogram(); |
| histogram.add(16); |
| assertEquals(15, histogram.min()); |
| assertEquals(17, histogram.max()); |
| } |
| |
| @Test |
| public void testMean() |
| { |
| { |
| EstimatedHistogram histogram = new EstimatedHistogram(); |
| for (int i = 0; i < 40; i++) |
| histogram.add(0); |
| for (int i = 0; i < 20; i++) |
| histogram.add(1); |
| for (int i = 0; i < 10; i++) |
| histogram.add(2); |
| assertEquals(70, histogram.count()); |
| assertEquals(2, histogram.mean()); |
| } |
| { |
| EstimatedHistogram histogram = new EstimatedHistogram(90, true); |
| for (int i = 0; i < 40; i++) |
| histogram.add(0); |
| for (int i = 0; i < 20; i++) |
| histogram.add(1); |
| for (int i = 0; i < 10; i++) |
| histogram.add(2); |
| assertEquals(70, histogram.count()); |
| assertEquals(1, histogram.mean()); |
| } |
| } |
| |
| @Test |
| public void testFindingCorrectBuckets() |
| { |
| EstimatedHistogram histogram = new EstimatedHistogram(); |
| histogram.add(23282687); |
| assert !histogram.isOverflowed(); |
| assertEquals(1, histogram.getBuckets(false)[histogram.buckets.length() - 2]); |
| |
| histogram.add(9); |
| assertEquals(1, histogram.getBuckets(false)[8]); |
| |
| histogram.add(20); |
| histogram.add(21); |
| histogram.add(22); |
| assertEquals(2, histogram.getBuckets(false)[13]); |
| assertEquals(5021848, histogram.mean()); |
| } |
| |
| @Test |
| public void testPercentile() |
| { |
| { |
| EstimatedHistogram histogram = new EstimatedHistogram(); |
| // percentile of empty histogram is 0 |
| assertEquals(0, histogram.percentile(0.99)); |
| |
| histogram.add(1); |
| // percentile of a histogram with one element should be that element |
| assertEquals(1, histogram.percentile(0.99)); |
| |
| histogram.add(10); |
| assertEquals(10, histogram.percentile(0.99)); |
| } |
| |
| { |
| EstimatedHistogram histogram = new EstimatedHistogram(); |
| |
| histogram.add(1); |
| histogram.add(2); |
| histogram.add(3); |
| histogram.add(4); |
| histogram.add(5); |
| |
| assertEquals(0, histogram.percentile(0.00)); |
| assertEquals(3, histogram.percentile(0.50)); |
| assertEquals(3, histogram.percentile(0.60)); |
| assertEquals(5, histogram.percentile(1.00)); |
| } |
| |
| { |
| EstimatedHistogram histogram = new EstimatedHistogram(); |
| |
| for (int i = 11; i <= 20; i++) |
| histogram.add(i); |
| |
| // Right now the histogram looks like: |
| // 10 12 14 17 20 |
| // 0 2 2 3 3 |
| // %: 0 20 40 70 100 |
| assertEquals(12, histogram.percentile(0.01)); |
| assertEquals(14, histogram.percentile(0.30)); |
| assertEquals(17, histogram.percentile(0.50)); |
| assertEquals(17, histogram.percentile(0.60)); |
| assertEquals(20, histogram.percentile(0.80)); |
| } |
| { |
| EstimatedHistogram histogram = new EstimatedHistogram(90, true); |
| histogram.add(0); |
| histogram.add(0); |
| histogram.add(1); |
| |
| assertEquals(0, histogram.percentile(0.5)); |
| assertEquals(1, histogram.percentile(0.99)); |
| } |
| } |
| } |