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<pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Licensed to the Apache Software Foundation (ASF) under one<a name="line.2"></a>
<span class="sourceLineNo">003</span> * or more contributor license agreements. See the NOTICE file<a name="line.3"></a>
<span class="sourceLineNo">004</span> * distributed with this work for additional information<a name="line.4"></a>
<span class="sourceLineNo">005</span> * regarding copyright ownership. The ASF licenses this file<a name="line.5"></a>
<span class="sourceLineNo">006</span> * to you under the Apache License, Version 2.0 (the<a name="line.6"></a>
<span class="sourceLineNo">007</span> * "License"); you may not use this file except in compliance<a name="line.7"></a>
<span class="sourceLineNo">008</span> * with the License. You may obtain a copy of the License at<a name="line.8"></a>
<span class="sourceLineNo">009</span> *<a name="line.9"></a>
<span class="sourceLineNo">010</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.10"></a>
<span class="sourceLineNo">011</span> *<a name="line.11"></a>
<span class="sourceLineNo">012</span> * Unless required by applicable law or agreed to in writing, software<a name="line.12"></a>
<span class="sourceLineNo">013</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.13"></a>
<span class="sourceLineNo">014</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.14"></a>
<span class="sourceLineNo">015</span> * See the License for the specific language governing permissions and<a name="line.15"></a>
<span class="sourceLineNo">016</span> * limitations under the License.<a name="line.16"></a>
<span class="sourceLineNo">017</span> */<a name="line.17"></a>
<span class="sourceLineNo">018</span>package org.apache.hadoop.hbase.client;<a name="line.18"></a>
<span class="sourceLineNo">019</span><a name="line.19"></a>
<span class="sourceLineNo">020</span>import static org.apache.hadoop.hbase.client.ConnectionUtils.filterCells;<a name="line.20"></a>
<span class="sourceLineNo">021</span><a name="line.21"></a>
<span class="sourceLineNo">022</span>import java.io.IOException;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import java.util.ArrayDeque;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import java.util.ArrayList;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import java.util.Deque;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import java.util.List;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import org.apache.hadoop.hbase.Cell;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import org.apache.hadoop.hbase.CellUtil;<a name="line.28"></a>
<span class="sourceLineNo">029</span>import org.apache.hadoop.hbase.util.Bytes;<a name="line.29"></a>
<span class="sourceLineNo">030</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.30"></a>
<span class="sourceLineNo">031</span><a name="line.31"></a>
<span class="sourceLineNo">032</span>/**<a name="line.32"></a>
<span class="sourceLineNo">033</span> * A scan result cache for batched scan, i.e,<a name="line.33"></a>
<span class="sourceLineNo">034</span> * {@code scan.getBatch() &gt; 0 &amp;&amp; !scan.getAllowPartialResults()}.<a name="line.34"></a>
<span class="sourceLineNo">035</span> * &lt;p&gt;<a name="line.35"></a>
<span class="sourceLineNo">036</span> * If user setBatch(5) and rpc returns 3+5+5+5+3 cells, we should return 5+5+5+5+1 to user. setBatch<a name="line.36"></a>
<span class="sourceLineNo">037</span> * doesn't mean setAllowPartialResult(true).<a name="line.37"></a>
<span class="sourceLineNo">038</span> * @since 2.0.0<a name="line.38"></a>
<span class="sourceLineNo">039</span> */<a name="line.39"></a>
<span class="sourceLineNo">040</span>@InterfaceAudience.Private<a name="line.40"></a>
<span class="sourceLineNo">041</span>public class BatchScanResultCache implements ScanResultCache {<a name="line.41"></a>
<span class="sourceLineNo">042</span><a name="line.42"></a>
<span class="sourceLineNo">043</span> private final int batch;<a name="line.43"></a>
<span class="sourceLineNo">044</span><a name="line.44"></a>
<span class="sourceLineNo">045</span> // used to filter out the cells that already returned to user as we always start from the<a name="line.45"></a>
<span class="sourceLineNo">046</span> // beginning of a row when retry.<a name="line.46"></a>
<span class="sourceLineNo">047</span> private Cell lastCell;<a name="line.47"></a>
<span class="sourceLineNo">048</span><a name="line.48"></a>
<span class="sourceLineNo">049</span> private boolean lastResultPartial;<a name="line.49"></a>
<span class="sourceLineNo">050</span><a name="line.50"></a>
<span class="sourceLineNo">051</span> private final Deque&lt;Result&gt; partialResults = new ArrayDeque&lt;&gt;();<a name="line.51"></a>
<span class="sourceLineNo">052</span><a name="line.52"></a>
<span class="sourceLineNo">053</span> private int numCellsOfPartialResults;<a name="line.53"></a>
<span class="sourceLineNo">054</span><a name="line.54"></a>
<span class="sourceLineNo">055</span> private int numberOfCompleteRows;<a name="line.55"></a>
<span class="sourceLineNo">056</span><a name="line.56"></a>
<span class="sourceLineNo">057</span> public BatchScanResultCache(int batch) {<a name="line.57"></a>
<span class="sourceLineNo">058</span> this.batch = batch;<a name="line.58"></a>
<span class="sourceLineNo">059</span> }<a name="line.59"></a>
<span class="sourceLineNo">060</span><a name="line.60"></a>
<span class="sourceLineNo">061</span> private void recordLastResult(Result result) {<a name="line.61"></a>
<span class="sourceLineNo">062</span> lastCell = result.rawCells()[result.rawCells().length - 1];<a name="line.62"></a>
<span class="sourceLineNo">063</span> lastResultPartial = result.mayHaveMoreCellsInRow();<a name="line.63"></a>
<span class="sourceLineNo">064</span> }<a name="line.64"></a>
<span class="sourceLineNo">065</span><a name="line.65"></a>
<span class="sourceLineNo">066</span> private Result createCompletedResult() throws IOException {<a name="line.66"></a>
<span class="sourceLineNo">067</span> numberOfCompleteRows++;<a name="line.67"></a>
<span class="sourceLineNo">068</span> Result result = Result.createCompleteResult(partialResults);<a name="line.68"></a>
<span class="sourceLineNo">069</span> partialResults.clear();<a name="line.69"></a>
<span class="sourceLineNo">070</span> numCellsOfPartialResults = 0;<a name="line.70"></a>
<span class="sourceLineNo">071</span> return result;<a name="line.71"></a>
<span class="sourceLineNo">072</span> }<a name="line.72"></a>
<span class="sourceLineNo">073</span><a name="line.73"></a>
<span class="sourceLineNo">074</span> // Add new result to the partial list and return a batched Result if caching size exceed batching<a name="line.74"></a>
<span class="sourceLineNo">075</span> // limit. As the RS will also respect the scan.getBatch, we can make sure that we will get only<a name="line.75"></a>
<span class="sourceLineNo">076</span> // one Result back at most(or null, which means we do not have enough cells).<a name="line.76"></a>
<span class="sourceLineNo">077</span> private Result regroupResults(Result result) {<a name="line.77"></a>
<span class="sourceLineNo">078</span> partialResults.addLast(result);<a name="line.78"></a>
<span class="sourceLineNo">079</span> numCellsOfPartialResults += result.size();<a name="line.79"></a>
<span class="sourceLineNo">080</span> if (numCellsOfPartialResults &lt; batch) {<a name="line.80"></a>
<span class="sourceLineNo">081</span> return null;<a name="line.81"></a>
<span class="sourceLineNo">082</span> }<a name="line.82"></a>
<span class="sourceLineNo">083</span> Cell[] cells = new Cell[batch];<a name="line.83"></a>
<span class="sourceLineNo">084</span> int cellCount = 0;<a name="line.84"></a>
<span class="sourceLineNo">085</span> boolean stale = false;<a name="line.85"></a>
<span class="sourceLineNo">086</span> for (;;) {<a name="line.86"></a>
<span class="sourceLineNo">087</span> Result r = partialResults.pollFirst();<a name="line.87"></a>
<span class="sourceLineNo">088</span> stale = stale || r.isStale();<a name="line.88"></a>
<span class="sourceLineNo">089</span> int newCellCount = cellCount + r.size();<a name="line.89"></a>
<span class="sourceLineNo">090</span> if (newCellCount &gt; batch) {<a name="line.90"></a>
<span class="sourceLineNo">091</span> // We have more cells than expected, so split the current result<a name="line.91"></a>
<span class="sourceLineNo">092</span> int len = batch - cellCount;<a name="line.92"></a>
<span class="sourceLineNo">093</span> System.arraycopy(r.rawCells(), 0, cells, cellCount, len);<a name="line.93"></a>
<span class="sourceLineNo">094</span> Cell[] remainingCells = new Cell[r.size() - len];<a name="line.94"></a>
<span class="sourceLineNo">095</span> System.arraycopy(r.rawCells(), len, remainingCells, 0, r.size() - len);<a name="line.95"></a>
<span class="sourceLineNo">096</span> partialResults.addFirst(<a name="line.96"></a>
<span class="sourceLineNo">097</span> Result.create(remainingCells, r.getExists(), r.isStale(), r.mayHaveMoreCellsInRow()));<a name="line.97"></a>
<span class="sourceLineNo">098</span> break;<a name="line.98"></a>
<span class="sourceLineNo">099</span> }<a name="line.99"></a>
<span class="sourceLineNo">100</span> System.arraycopy(r.rawCells(), 0, cells, cellCount, r.size());<a name="line.100"></a>
<span class="sourceLineNo">101</span> if (newCellCount == batch) {<a name="line.101"></a>
<span class="sourceLineNo">102</span> break;<a name="line.102"></a>
<span class="sourceLineNo">103</span> }<a name="line.103"></a>
<span class="sourceLineNo">104</span> cellCount = newCellCount;<a name="line.104"></a>
<span class="sourceLineNo">105</span> }<a name="line.105"></a>
<span class="sourceLineNo">106</span> numCellsOfPartialResults -= batch;<a name="line.106"></a>
<span class="sourceLineNo">107</span> return Result.create(cells, null, stale,<a name="line.107"></a>
<span class="sourceLineNo">108</span> result.mayHaveMoreCellsInRow() || !partialResults.isEmpty());<a name="line.108"></a>
<span class="sourceLineNo">109</span> }<a name="line.109"></a>
<span class="sourceLineNo">110</span><a name="line.110"></a>
<span class="sourceLineNo">111</span> @Override<a name="line.111"></a>
<span class="sourceLineNo">112</span> public Result[] addAndGet(Result[] results, boolean isHeartbeatMessage) throws IOException {<a name="line.112"></a>
<span class="sourceLineNo">113</span> if (results.length == 0) {<a name="line.113"></a>
<span class="sourceLineNo">114</span> if (!isHeartbeatMessage) {<a name="line.114"></a>
<span class="sourceLineNo">115</span> if (!partialResults.isEmpty()) {<a name="line.115"></a>
<span class="sourceLineNo">116</span> return new Result[] { createCompletedResult() };<a name="line.116"></a>
<span class="sourceLineNo">117</span> }<a name="line.117"></a>
<span class="sourceLineNo">118</span> if (lastResultPartial) {<a name="line.118"></a>
<span class="sourceLineNo">119</span> // An empty non heartbeat result indicate that there must be a row change. So if the<a name="line.119"></a>
<span class="sourceLineNo">120</span> // lastResultPartial is true then we need to increase numberOfCompleteRows.<a name="line.120"></a>
<span class="sourceLineNo">121</span> numberOfCompleteRows++;<a name="line.121"></a>
<span class="sourceLineNo">122</span> }<a name="line.122"></a>
<span class="sourceLineNo">123</span> }<a name="line.123"></a>
<span class="sourceLineNo">124</span> return EMPTY_RESULT_ARRAY;<a name="line.124"></a>
<span class="sourceLineNo">125</span> }<a name="line.125"></a>
<span class="sourceLineNo">126</span> List&lt;Result&gt; regroupedResults = new ArrayList&lt;&gt;();<a name="line.126"></a>
<span class="sourceLineNo">127</span> for (Result result : results) {<a name="line.127"></a>
<span class="sourceLineNo">128</span> result = filterCells(result, lastCell);<a name="line.128"></a>
<span class="sourceLineNo">129</span> if (result == null) {<a name="line.129"></a>
<span class="sourceLineNo">130</span> continue;<a name="line.130"></a>
<span class="sourceLineNo">131</span> }<a name="line.131"></a>
<span class="sourceLineNo">132</span> if (!partialResults.isEmpty()) {<a name="line.132"></a>
<span class="sourceLineNo">133</span> if (!Bytes.equals(partialResults.peek().getRow(), result.getRow())) {<a name="line.133"></a>
<span class="sourceLineNo">134</span> // there is a row change<a name="line.134"></a>
<span class="sourceLineNo">135</span> regroupedResults.add(createCompletedResult());<a name="line.135"></a>
<span class="sourceLineNo">136</span> }<a name="line.136"></a>
<span class="sourceLineNo">137</span> } else if (lastResultPartial &amp;&amp; !CellUtil.matchingRows(lastCell, result.getRow())) {<a name="line.137"></a>
<span class="sourceLineNo">138</span> // As for batched scan we may return partial results to user if we reach the batch limit, so<a name="line.138"></a>
<span class="sourceLineNo">139</span> // here we need to use lastCell to determine if there is row change and increase<a name="line.139"></a>
<span class="sourceLineNo">140</span> // numberOfCompleteRows.<a name="line.140"></a>
<span class="sourceLineNo">141</span> numberOfCompleteRows++;<a name="line.141"></a>
<span class="sourceLineNo">142</span> }<a name="line.142"></a>
<span class="sourceLineNo">143</span> // check if we have a row change<a name="line.143"></a>
<span class="sourceLineNo">144</span> if (<a name="line.144"></a>
<span class="sourceLineNo">145</span> !partialResults.isEmpty() &amp;&amp; !Bytes.equals(partialResults.peek().getRow(), result.getRow())<a name="line.145"></a>
<span class="sourceLineNo">146</span> ) {<a name="line.146"></a>
<span class="sourceLineNo">147</span> regroupedResults.add(createCompletedResult());<a name="line.147"></a>
<span class="sourceLineNo">148</span> }<a name="line.148"></a>
<span class="sourceLineNo">149</span> Result regroupedResult = regroupResults(result);<a name="line.149"></a>
<span class="sourceLineNo">150</span> if (regroupedResult != null) {<a name="line.150"></a>
<span class="sourceLineNo">151</span> if (!regroupedResult.mayHaveMoreCellsInRow()) {<a name="line.151"></a>
<span class="sourceLineNo">152</span> numberOfCompleteRows++;<a name="line.152"></a>
<span class="sourceLineNo">153</span> }<a name="line.153"></a>
<span class="sourceLineNo">154</span> regroupedResults.add(regroupedResult);<a name="line.154"></a>
<span class="sourceLineNo">155</span> // only update last cell when we actually return it to user.<a name="line.155"></a>
<span class="sourceLineNo">156</span> recordLastResult(regroupedResult);<a name="line.156"></a>
<span class="sourceLineNo">157</span> }<a name="line.157"></a>
<span class="sourceLineNo">158</span> if (!result.mayHaveMoreCellsInRow() &amp;&amp; !partialResults.isEmpty()) {<a name="line.158"></a>
<span class="sourceLineNo">159</span> // We are done for this row<a name="line.159"></a>
<span class="sourceLineNo">160</span> regroupedResults.add(createCompletedResult());<a name="line.160"></a>
<span class="sourceLineNo">161</span> }<a name="line.161"></a>
<span class="sourceLineNo">162</span> }<a name="line.162"></a>
<span class="sourceLineNo">163</span> return regroupedResults.toArray(new Result[0]);<a name="line.163"></a>
<span class="sourceLineNo">164</span> }<a name="line.164"></a>
<span class="sourceLineNo">165</span><a name="line.165"></a>
<span class="sourceLineNo">166</span> @Override<a name="line.166"></a>
<span class="sourceLineNo">167</span> public void clear() {<a name="line.167"></a>
<span class="sourceLineNo">168</span> partialResults.clear();<a name="line.168"></a>
<span class="sourceLineNo">169</span> numCellsOfPartialResults = 0;<a name="line.169"></a>
<span class="sourceLineNo">170</span> }<a name="line.170"></a>
<span class="sourceLineNo">171</span><a name="line.171"></a>
<span class="sourceLineNo">172</span> @Override<a name="line.172"></a>
<span class="sourceLineNo">173</span> public int numberOfCompleteRows() {<a name="line.173"></a>
<span class="sourceLineNo">174</span> return numberOfCompleteRows;<a name="line.174"></a>
<span class="sourceLineNo">175</span> }<a name="line.175"></a>
<span class="sourceLineNo">176</span>}<a name="line.176"></a>
</pre>
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