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| <pre><span class="source-line-no">001</span><span id="line-1">/*</span> |
| <span class="source-line-no">002</span><span id="line-2"> * Licensed to the Apache Software Foundation (ASF) under one</span> |
| <span class="source-line-no">003</span><span id="line-3"> * or more contributor license agreements. See the NOTICE file</span> |
| <span class="source-line-no">004</span><span id="line-4"> * distributed with this work for additional information</span> |
| <span class="source-line-no">005</span><span id="line-5"> * regarding copyright ownership. The ASF licenses this file</span> |
| <span class="source-line-no">006</span><span id="line-6"> * to you under the Apache License, Version 2.0 (the</span> |
| <span class="source-line-no">007</span><span id="line-7"> * "License"); you may not use this file except in compliance</span> |
| <span class="source-line-no">008</span><span id="line-8"> * with the License. You may obtain a copy of the License at</span> |
| <span class="source-line-no">009</span><span id="line-9"> *</span> |
| <span class="source-line-no">010</span><span id="line-10"> * http://www.apache.org/licenses/LICENSE-2.0</span> |
| <span class="source-line-no">011</span><span id="line-11"> *</span> |
| <span class="source-line-no">012</span><span id="line-12"> * Unless required by applicable law or agreed to in writing, software</span> |
| <span class="source-line-no">013</span><span id="line-13"> * distributed under the License is distributed on an "AS IS" BASIS,</span> |
| <span class="source-line-no">014</span><span id="line-14"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span> |
| <span class="source-line-no">015</span><span id="line-15"> * See the License for the specific language governing permissions and</span> |
| <span class="source-line-no">016</span><span id="line-16"> * limitations under the License.</span> |
| <span class="source-line-no">017</span><span id="line-17"> */</span> |
| <span class="source-line-no">018</span><span id="line-18">package org.apache.hadoop.hbase.regionserver;</span> |
| <span class="source-line-no">019</span><span id="line-19"></span> |
| <span class="source-line-no">020</span><span id="line-20">import java.util.concurrent.ThreadLocalRandom;</span> |
| <span class="source-line-no">021</span><span id="line-21">import org.apache.hadoop.conf.Configuration;</span> |
| <span class="source-line-no">022</span><span id="line-22">import org.apache.yetus.audience.InterfaceAudience;</span> |
| <span class="source-line-no">023</span><span id="line-23"></span> |
| <span class="source-line-no">024</span><span id="line-24">/**</span> |
| <span class="source-line-no">025</span><span id="line-25"> * Adaptive is a heuristic that chooses whether to apply data compaction or not based on the level</span> |
| <span class="source-line-no">026</span><span id="line-26"> * of redundancy in the data. Adaptive triggers redundancy elimination only for those stores where</span> |
| <span class="source-line-no">027</span><span id="line-27"> * positive impact is expected. Adaptive uses two parameters to determine whether to perform</span> |
| <span class="source-line-no">028</span><span id="line-28"> * redundancy elimination. The first parameter, u, estimates the ratio of unique keys in the memory</span> |
| <span class="source-line-no">029</span><span id="line-29"> * store based on the fraction of unique keys encountered during the previous merge of segment</span> |
| <span class="source-line-no">030</span><span id="line-30"> * indices. The second is the perceived probability (compactionProbability) that the store can</span> |
| <span class="source-line-no">031</span><span id="line-31"> * benefit from redundancy elimination. Initially, compactionProbability=0.5; it then grows</span> |
| <span class="source-line-no">032</span><span id="line-32"> * exponentially by 2% whenever a compaction is successful and decreased by 2% whenever a compaction</span> |
| <span class="source-line-no">033</span><span id="line-33"> * did not meet the expectation. It is reset back to the default value (namely 0.5) upon disk flush.</span> |
| <span class="source-line-no">034</span><span id="line-34"> * Adaptive triggers redundancy elimination with probability compactionProbability if the fraction</span> |
| <span class="source-line-no">035</span><span id="line-35"> * of redundant keys 1-u exceeds a parameter threshold compactionThreshold.</span> |
| <span class="source-line-no">036</span><span id="line-36"> */</span> |
| <span class="source-line-no">037</span><span id="line-37">@InterfaceAudience.Private</span> |
| <span class="source-line-no">038</span><span id="line-38">public class AdaptiveMemStoreCompactionStrategy extends MemStoreCompactionStrategy {</span> |
| <span class="source-line-no">039</span><span id="line-39"> private static final String NAME = "ADAPTIVE";</span> |
| <span class="source-line-no">040</span><span id="line-40"> public static final String ADAPTIVE_COMPACTION_THRESHOLD_KEY =</span> |
| <span class="source-line-no">041</span><span id="line-41"> "hbase.hregion.compacting.memstore.adaptive.compaction.threshold";</span> |
| <span class="source-line-no">042</span><span id="line-42"> private static final double ADAPTIVE_COMPACTION_THRESHOLD_DEFAULT = 0.5;</span> |
| <span class="source-line-no">043</span><span id="line-43"> public static final String ADAPTIVE_INITIAL_COMPACTION_PROBABILITY_KEY =</span> |
| <span class="source-line-no">044</span><span id="line-44"> "hbase.hregion.compacting.memstore.adaptive.compaction.probability";</span> |
| <span class="source-line-no">045</span><span id="line-45"> private static final double ADAPTIVE_INITIAL_COMPACTION_PROBABILITY_DEFAULT = 0.5;</span> |
| <span class="source-line-no">046</span><span id="line-46"> private static final double ADAPTIVE_PROBABILITY_FACTOR = 1.02;</span> |
| <span class="source-line-no">047</span><span id="line-47"></span> |
| <span class="source-line-no">048</span><span id="line-48"> private double compactionThreshold;</span> |
| <span class="source-line-no">049</span><span id="line-49"> private double initialCompactionProbability;</span> |
| <span class="source-line-no">050</span><span id="line-50"> private double compactionProbability;</span> |
| <span class="source-line-no">051</span><span id="line-51"> private double numCellsInVersionedList = 0;</span> |
| <span class="source-line-no">052</span><span id="line-52"> private boolean compacted = false;</span> |
| <span class="source-line-no">053</span><span id="line-53"></span> |
| <span class="source-line-no">054</span><span id="line-54"> public AdaptiveMemStoreCompactionStrategy(Configuration conf, String cfName) {</span> |
| <span class="source-line-no">055</span><span id="line-55"> super(conf, cfName);</span> |
| <span class="source-line-no">056</span><span id="line-56"> compactionThreshold =</span> |
| <span class="source-line-no">057</span><span id="line-57"> conf.getDouble(ADAPTIVE_COMPACTION_THRESHOLD_KEY, ADAPTIVE_COMPACTION_THRESHOLD_DEFAULT);</span> |
| <span class="source-line-no">058</span><span id="line-58"> initialCompactionProbability = conf.getDouble(ADAPTIVE_INITIAL_COMPACTION_PROBABILITY_KEY,</span> |
| <span class="source-line-no">059</span><span id="line-59"> ADAPTIVE_INITIAL_COMPACTION_PROBABILITY_DEFAULT);</span> |
| <span class="source-line-no">060</span><span id="line-60"> resetStats();</span> |
| <span class="source-line-no">061</span><span id="line-61"> }</span> |
| <span class="source-line-no">062</span><span id="line-62"></span> |
| <span class="source-line-no">063</span><span id="line-63"> @Override</span> |
| <span class="source-line-no">064</span><span id="line-64"> public Action getAction(VersionedSegmentsList versionedList) {</span> |
| <span class="source-line-no">065</span><span id="line-65"> if (versionedList.getEstimatedUniquesFrac() < 1.0 - compactionThreshold) {</span> |
| <span class="source-line-no">066</span><span id="line-66"> double r = ThreadLocalRandom.current().nextDouble();</span> |
| <span class="source-line-no">067</span><span id="line-67"> if (r < compactionProbability) {</span> |
| <span class="source-line-no">068</span><span id="line-68"> numCellsInVersionedList = versionedList.getNumOfCells();</span> |
| <span class="source-line-no">069</span><span id="line-69"> compacted = true;</span> |
| <span class="source-line-no">070</span><span id="line-70"> return compact(versionedList,</span> |
| <span class="source-line-no">071</span><span id="line-71"> getName() + " (compaction probability=" + compactionProbability + ")");</span> |
| <span class="source-line-no">072</span><span id="line-72"> }</span> |
| <span class="source-line-no">073</span><span id="line-73"> }</span> |
| <span class="source-line-no">074</span><span id="line-74"> compacted = false;</span> |
| <span class="source-line-no">075</span><span id="line-75"> return simpleMergeOrFlatten(versionedList,</span> |
| <span class="source-line-no">076</span><span id="line-76"> getName() + " (compaction probability=" + compactionProbability + ")");</span> |
| <span class="source-line-no">077</span><span id="line-77"> }</span> |
| <span class="source-line-no">078</span><span id="line-78"></span> |
| <span class="source-line-no">079</span><span id="line-79"> @Override</span> |
| <span class="source-line-no">080</span><span id="line-80"> public void updateStats(Segment replacement) {</span> |
| <span class="source-line-no">081</span><span id="line-81"> if (compacted) {</span> |
| <span class="source-line-no">082</span><span id="line-82"> if (replacement.getCellsCount() / numCellsInVersionedList < 1.0 - compactionThreshold) {</span> |
| <span class="source-line-no">083</span><span id="line-83"> // compaction was a good decision - increase probability</span> |
| <span class="source-line-no">084</span><span id="line-84"> compactionProbability *= ADAPTIVE_PROBABILITY_FACTOR;</span> |
| <span class="source-line-no">085</span><span id="line-85"> if (compactionProbability > 1.0) {</span> |
| <span class="source-line-no">086</span><span id="line-86"> compactionProbability = 1.0;</span> |
| <span class="source-line-no">087</span><span id="line-87"> }</span> |
| <span class="source-line-no">088</span><span id="line-88"> } else {</span> |
| <span class="source-line-no">089</span><span id="line-89"> // compaction was NOT a good decision - decrease probability</span> |
| <span class="source-line-no">090</span><span id="line-90"> compactionProbability /= ADAPTIVE_PROBABILITY_FACTOR;</span> |
| <span class="source-line-no">091</span><span id="line-91"> }</span> |
| <span class="source-line-no">092</span><span id="line-92"> }</span> |
| <span class="source-line-no">093</span><span id="line-93"> }</span> |
| <span class="source-line-no">094</span><span id="line-94"></span> |
| <span class="source-line-no">095</span><span id="line-95"> @Override</span> |
| <span class="source-line-no">096</span><span id="line-96"> public void resetStats() {</span> |
| <span class="source-line-no">097</span><span id="line-97"> compactionProbability = initialCompactionProbability;</span> |
| <span class="source-line-no">098</span><span id="line-98"> }</span> |
| <span class="source-line-no">099</span><span id="line-99"></span> |
| <span class="source-line-no">100</span><span id="line-100"> @Override</span> |
| <span class="source-line-no">101</span><span id="line-101"> protected Action getMergingAction() {</span> |
| <span class="source-line-no">102</span><span id="line-102"> return Action.MERGE_COUNT_UNIQUE_KEYS;</span> |
| <span class="source-line-no">103</span><span id="line-103"> }</span> |
| <span class="source-line-no">104</span><span id="line-104"></span> |
| <span class="source-line-no">105</span><span id="line-105"> @Override</span> |
| <span class="source-line-no">106</span><span id="line-106"> protected Action getFlattenAction() {</span> |
| <span class="source-line-no">107</span><span id="line-107"> return Action.FLATTEN;</span> |
| <span class="source-line-no">108</span><span id="line-108"> }</span> |
| <span class="source-line-no">109</span><span id="line-109"></span> |
| <span class="source-line-no">110</span><span id="line-110"> @Override</span> |
| <span class="source-line-no">111</span><span id="line-111"> protected String getName() {</span> |
| <span class="source-line-no">112</span><span id="line-112"> return NAME;</span> |
| <span class="source-line-no">113</span><span id="line-113"> }</span> |
| <span class="source-line-no">114</span><span id="line-114">}</span> |
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| </pre> |
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