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| <pre><span class="sourceLineNo">001</span>/**<a name="line.1"></a> |
| <span class="sourceLineNo">002</span> *<a name="line.2"></a> |
| <span class="sourceLineNo">003</span> * Licensed to the Apache Software Foundation (ASF) under one<a name="line.3"></a> |
| <span class="sourceLineNo">004</span> * or more contributor license agreements. See the NOTICE file<a name="line.4"></a> |
| <span class="sourceLineNo">005</span> * distributed with this work for additional information<a name="line.5"></a> |
| <span class="sourceLineNo">006</span> * regarding copyright ownership. The ASF licenses this file<a name="line.6"></a> |
| <span class="sourceLineNo">007</span> * to you under the Apache License, Version 2.0 (the<a name="line.7"></a> |
| <span class="sourceLineNo">008</span> * "License"); you may not use this file except in compliance<a name="line.8"></a> |
| <span class="sourceLineNo">009</span> * with the License. You may obtain a copy of the License at<a name="line.9"></a> |
| <span class="sourceLineNo">010</span> *<a name="line.10"></a> |
| <span class="sourceLineNo">011</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.11"></a> |
| <span class="sourceLineNo">012</span> *<a name="line.12"></a> |
| <span class="sourceLineNo">013</span> * Unless required by applicable law or agreed to in writing, software<a name="line.13"></a> |
| <span class="sourceLineNo">014</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.14"></a> |
| <span class="sourceLineNo">015</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.15"></a> |
| <span class="sourceLineNo">016</span> * See the License for the specific language governing permissions and<a name="line.16"></a> |
| <span class="sourceLineNo">017</span> * limitations under the License.<a name="line.17"></a> |
| <span class="sourceLineNo">018</span> */<a name="line.18"></a> |
| <span class="sourceLineNo">019</span>package org.apache.hadoop.hbase.regionserver;<a name="line.19"></a> |
| <span class="sourceLineNo">020</span><a name="line.20"></a> |
| <span class="sourceLineNo">021</span>import java.util.Random;<a name="line.21"></a> |
| <span class="sourceLineNo">022</span><a name="line.22"></a> |
| <span class="sourceLineNo">023</span>import org.apache.hadoop.conf.Configuration;<a name="line.23"></a> |
| <span class="sourceLineNo">024</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.24"></a> |
| <span class="sourceLineNo">025</span><a name="line.25"></a> |
| <span class="sourceLineNo">026</span>/**<a name="line.26"></a> |
| <span class="sourceLineNo">027</span> * Adaptive is a heuristic that chooses whether to apply data compaction or not based on the<a name="line.27"></a> |
| <span class="sourceLineNo">028</span> * level of redundancy in the data. Adaptive triggers redundancy elimination only for those<a name="line.28"></a> |
| <span class="sourceLineNo">029</span> * stores where positive impact is expected.<a name="line.29"></a> |
| <span class="sourceLineNo">030</span> *<a name="line.30"></a> |
| <span class="sourceLineNo">031</span> * Adaptive uses two parameters to determine whether to perform redundancy elimination.<a name="line.31"></a> |
| <span class="sourceLineNo">032</span> * The first parameter, u, estimates the ratio of unique keys in the memory store based on the<a name="line.32"></a> |
| <span class="sourceLineNo">033</span> * fraction of unique keys encountered during the previous merge of segment indices.<a name="line.33"></a> |
| <span class="sourceLineNo">034</span> * The second is the perceived probability (compactionProbability) that the store can benefit from<a name="line.34"></a> |
| <span class="sourceLineNo">035</span> * redundancy elimination. Initially, compactionProbability=0.5; it then grows exponentially by<a name="line.35"></a> |
| <span class="sourceLineNo">036</span> * 2% whenever a compaction is successful and decreased by 2% whenever a compaction did not meet<a name="line.36"></a> |
| <span class="sourceLineNo">037</span> * the expectation. It is reset back to the default value (namely 0.5) upon disk flush.<a name="line.37"></a> |
| <span class="sourceLineNo">038</span> *<a name="line.38"></a> |
| <span class="sourceLineNo">039</span> * Adaptive triggers redundancy elimination with probability compactionProbability if the<a name="line.39"></a> |
| <span class="sourceLineNo">040</span> * fraction of redundant keys 1-u exceeds a parameter threshold compactionThreshold.<a name="line.40"></a> |
| <span class="sourceLineNo">041</span> */<a name="line.41"></a> |
| <span class="sourceLineNo">042</span>@InterfaceAudience.Private<a name="line.42"></a> |
| <span class="sourceLineNo">043</span>public class AdaptiveMemStoreCompactionStrategy extends MemStoreCompactionStrategy{<a name="line.43"></a> |
| <span class="sourceLineNo">044</span> private static final String NAME = "ADAPTIVE";<a name="line.44"></a> |
| <span class="sourceLineNo">045</span> public static final String ADAPTIVE_COMPACTION_THRESHOLD_KEY =<a name="line.45"></a> |
| <span class="sourceLineNo">046</span> "hbase.hregion.compacting.memstore.adaptive.compaction.threshold";<a name="line.46"></a> |
| <span class="sourceLineNo">047</span> private static final double ADAPTIVE_COMPACTION_THRESHOLD_DEFAULT = 0.5;<a name="line.47"></a> |
| <span class="sourceLineNo">048</span> public static final String ADAPTIVE_INITIAL_COMPACTION_PROBABILITY_KEY =<a name="line.48"></a> |
| <span class="sourceLineNo">049</span> "hbase.hregion.compacting.memstore.adaptive.compaction.probability";<a name="line.49"></a> |
| <span class="sourceLineNo">050</span> private static final double ADAPTIVE_INITIAL_COMPACTION_PROBABILITY_DEFAULT = 0.5;<a name="line.50"></a> |
| <span class="sourceLineNo">051</span> private static final double ADAPTIVE_PROBABILITY_FACTOR = 1.02;<a name="line.51"></a> |
| <span class="sourceLineNo">052</span><a name="line.52"></a> |
| <span class="sourceLineNo">053</span> private double compactionThreshold;<a name="line.53"></a> |
| <span class="sourceLineNo">054</span> private double initialCompactionProbability;<a name="line.54"></a> |
| <span class="sourceLineNo">055</span> private double compactionProbability;<a name="line.55"></a> |
| <span class="sourceLineNo">056</span> private Random rand = new Random();<a name="line.56"></a> |
| <span class="sourceLineNo">057</span> private double numCellsInVersionedList = 0;<a name="line.57"></a> |
| <span class="sourceLineNo">058</span> private boolean compacted = false;<a name="line.58"></a> |
| <span class="sourceLineNo">059</span><a name="line.59"></a> |
| <span class="sourceLineNo">060</span> public AdaptiveMemStoreCompactionStrategy(Configuration conf, String cfName) {<a name="line.60"></a> |
| <span class="sourceLineNo">061</span> super(conf, cfName);<a name="line.61"></a> |
| <span class="sourceLineNo">062</span> compactionThreshold = conf.getDouble(ADAPTIVE_COMPACTION_THRESHOLD_KEY,<a name="line.62"></a> |
| <span class="sourceLineNo">063</span> ADAPTIVE_COMPACTION_THRESHOLD_DEFAULT);<a name="line.63"></a> |
| <span class="sourceLineNo">064</span> initialCompactionProbability = conf.getDouble(ADAPTIVE_INITIAL_COMPACTION_PROBABILITY_KEY,<a name="line.64"></a> |
| <span class="sourceLineNo">065</span> ADAPTIVE_INITIAL_COMPACTION_PROBABILITY_DEFAULT);<a name="line.65"></a> |
| <span class="sourceLineNo">066</span> resetStats();<a name="line.66"></a> |
| <span class="sourceLineNo">067</span> }<a name="line.67"></a> |
| <span class="sourceLineNo">068</span><a name="line.68"></a> |
| <span class="sourceLineNo">069</span> @Override public Action getAction(VersionedSegmentsList versionedList) {<a name="line.69"></a> |
| <span class="sourceLineNo">070</span> if (versionedList.getEstimatedUniquesFrac() < 1.0 - compactionThreshold) {<a name="line.70"></a> |
| <span class="sourceLineNo">071</span> double r = rand.nextDouble();<a name="line.71"></a> |
| <span class="sourceLineNo">072</span> if(r < compactionProbability) {<a name="line.72"></a> |
| <span class="sourceLineNo">073</span> numCellsInVersionedList = versionedList.getNumOfCells();<a name="line.73"></a> |
| <span class="sourceLineNo">074</span> compacted = true;<a name="line.74"></a> |
| <span class="sourceLineNo">075</span> return compact(versionedList,<a name="line.75"></a> |
| <span class="sourceLineNo">076</span> getName() + " (compaction probability=" + compactionProbability + ")");<a name="line.76"></a> |
| <span class="sourceLineNo">077</span> }<a name="line.77"></a> |
| <span class="sourceLineNo">078</span> }<a name="line.78"></a> |
| <span class="sourceLineNo">079</span> compacted = false;<a name="line.79"></a> |
| <span class="sourceLineNo">080</span> return simpleMergeOrFlatten(versionedList,<a name="line.80"></a> |
| <span class="sourceLineNo">081</span> getName() + " (compaction probability=" + compactionProbability + ")");<a name="line.81"></a> |
| <span class="sourceLineNo">082</span> }<a name="line.82"></a> |
| <span class="sourceLineNo">083</span><a name="line.83"></a> |
| <span class="sourceLineNo">084</span> @Override<a name="line.84"></a> |
| <span class="sourceLineNo">085</span> public void updateStats(Segment replacement) {<a name="line.85"></a> |
| <span class="sourceLineNo">086</span> if(compacted) {<a name="line.86"></a> |
| <span class="sourceLineNo">087</span> if (replacement.getCellsCount() / numCellsInVersionedList < 1.0 - compactionThreshold) {<a name="line.87"></a> |
| <span class="sourceLineNo">088</span> // compaction was a good decision - increase probability<a name="line.88"></a> |
| <span class="sourceLineNo">089</span> compactionProbability *= ADAPTIVE_PROBABILITY_FACTOR;<a name="line.89"></a> |
| <span class="sourceLineNo">090</span> if(compactionProbability > 1.0) {<a name="line.90"></a> |
| <span class="sourceLineNo">091</span> compactionProbability = 1.0;<a name="line.91"></a> |
| <span class="sourceLineNo">092</span> }<a name="line.92"></a> |
| <span class="sourceLineNo">093</span> } else {<a name="line.93"></a> |
| <span class="sourceLineNo">094</span> // compaction was NOT a good decision - decrease probability<a name="line.94"></a> |
| <span class="sourceLineNo">095</span> compactionProbability /= ADAPTIVE_PROBABILITY_FACTOR;<a name="line.95"></a> |
| <span class="sourceLineNo">096</span> }<a name="line.96"></a> |
| <span class="sourceLineNo">097</span> }<a name="line.97"></a> |
| <span class="sourceLineNo">098</span> }<a name="line.98"></a> |
| <span class="sourceLineNo">099</span><a name="line.99"></a> |
| <span class="sourceLineNo">100</span> @Override<a name="line.100"></a> |
| <span class="sourceLineNo">101</span> public void resetStats() {<a name="line.101"></a> |
| <span class="sourceLineNo">102</span> compactionProbability = initialCompactionProbability;<a name="line.102"></a> |
| <span class="sourceLineNo">103</span> }<a name="line.103"></a> |
| <span class="sourceLineNo">104</span><a name="line.104"></a> |
| <span class="sourceLineNo">105</span> @Override<a name="line.105"></a> |
| <span class="sourceLineNo">106</span> protected Action getMergingAction() {<a name="line.106"></a> |
| <span class="sourceLineNo">107</span> return Action.MERGE_COUNT_UNIQUE_KEYS;<a name="line.107"></a> |
| <span class="sourceLineNo">108</span> }<a name="line.108"></a> |
| <span class="sourceLineNo">109</span><a name="line.109"></a> |
| <span class="sourceLineNo">110</span> @Override<a name="line.110"></a> |
| <span class="sourceLineNo">111</span> protected Action getFlattenAction() {<a name="line.111"></a> |
| <span class="sourceLineNo">112</span> return Action.FLATTEN;<a name="line.112"></a> |
| <span class="sourceLineNo">113</span> }<a name="line.113"></a> |
| <span class="sourceLineNo">114</span><a name="line.114"></a> |
| <span class="sourceLineNo">115</span> @Override<a name="line.115"></a> |
| <span class="sourceLineNo">116</span> protected String getName() {<a name="line.116"></a> |
| <span class="sourceLineNo">117</span> return NAME;<a name="line.117"></a> |
| <span class="sourceLineNo">118</span> }<a name="line.118"></a> |
| <span class="sourceLineNo">119</span>}<a name="line.119"></a> |
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