1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with this
4 * work for additional information regarding copyright ownership. The ASF
5 * licenses this file to you under the Apache License, Version 2.0 (the
6 * "License"); you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
13 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
14 * License for the specific language governing permissions and limitations
15 * under the License.
16 */
17 package org.apache.hadoop.hbase.util.test;
18
19 import java.util.Random;
20
21 import org.apache.hadoop.hbase.classification.InterfaceAudience;
22 import org.apache.hadoop.hbase.util.Bytes;
23 import org.apache.hadoop.hbase.util.MD5Hash;
24
25 /**
26 * A generator of random keys and values for load testing. Keys are generated
27 * by converting numeric indexes to strings and prefixing them with an MD5
28 * hash. Values are generated by selecting value size in the configured range
29 * and generating a pseudo-random sequence of bytes seeded by key, column
30 * qualifier, and value size.
31 */
32 @InterfaceAudience.Private
33 public class LoadTestKVGenerator {
34
35 /** A random number generator for determining value size */
36 private Random randomForValueSize = new Random();
37
38 private final int minValueSize;
39 private final int maxValueSize;
40
41 public LoadTestKVGenerator(int minValueSize, int maxValueSize) {
42 if (minValueSize <= 0 || maxValueSize <= 0) {
43 throw new IllegalArgumentException("Invalid min/max value sizes: " +
44 minValueSize + ", " + maxValueSize);
45 }
46 this.minValueSize = minValueSize;
47 this.maxValueSize = maxValueSize;
48 }
49
50 /**
51 * Verifies that the given byte array is the same as what would be generated
52 * for the given seed strings (row/cf/column/...). We are assuming that the
53 * value size is correct, and only verify the actual bytes. However, if the
54 * min/max value sizes are set sufficiently high, an accidental match should be
55 * extremely improbable.
56 */
57 public static boolean verify(byte[] value, byte[]... seedStrings) {
58 byte[] expectedData = getValueForRowColumn(value.length, seedStrings);
59 return Bytes.equals(expectedData, value);
60 }
61
62 /**
63 * Converts the given key to string, and prefixes it with the MD5 hash of
64 * the index's string representation.
65 */
66 public static String md5PrefixedKey(long key) {
67 String stringKey = Long.toString(key);
68 String md5hash = MD5Hash.getMD5AsHex(Bytes.toBytes(stringKey));
69
70 // flip the key to randomize
71 return md5hash + "-" + stringKey;
72 }
73
74 /**
75 * Generates a value for the given key index and column qualifier. Size is
76 * selected randomly in the configured range. The generated value depends
77 * only on the combination of the strings passed (key/cf/column/...) and the selected
78 * value size. This allows to verify the actual value bytes when reading, as done
79 * in {#verify(byte[], byte[]...)}
80 * This method is as thread-safe as Random class. It appears that the worst bug ever
81 * found with the latter is that multiple threads will get some duplicate values, which
82 * we don't care about.
83 */
84 public byte[] generateRandomSizeValue(byte[]... seedStrings) {
85 int dataSize = minValueSize;
86 if(minValueSize != maxValueSize) {
87 dataSize = minValueSize + randomForValueSize.nextInt(Math.abs(maxValueSize - minValueSize));
88 }
89 return getValueForRowColumn(dataSize, seedStrings);
90 }
91
92 /**
93 * Generates random bytes of the given size for the given row and column
94 * qualifier. The random seed is fully determined by these parameters.
95 */
96 private static byte[] getValueForRowColumn(int dataSize, byte[]... seedStrings) {
97 long seed = dataSize;
98 for (byte[] str : seedStrings) {
99 seed += Bytes.toString(str).hashCode();
100 }
101 Random seededRandom = new Random(seed);
102 byte[] randomBytes = new byte[dataSize];
103 seededRandom.nextBytes(randomBytes);
104 return randomBytes;
105 }
106
107 }