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Posted to commits@hbase.apache.org by mi...@apache.org on 2016/02/12 22:25:46 UTC

[21/51] [partial] hbase-site git commit: Published site at 85e1d9a109341c5f4aabb0e82c96ab52e99a6d72.

http://git-wip-us.apache.org/repos/asf/hbase-site/blob/526c7822/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MemStoreScanner.html
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diff --git a/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MemStoreScanner.html b/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MemStoreScanner.html
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html lang="en">
+<head>
+<title>Source code</title>
+<link rel="stylesheet" type="text/css" href="../../../../../../stylesheet.css" title="Style">
+</head>
+<body>
+<div class="sourceContainer">
+<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><a name="line.19"></a>
+<span class="sourceLineNo">020</span>package org.apache.hadoop.hbase.regionserver;<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.List;<a name="line.23"></a>
+<span class="sourceLineNo">024</span><a name="line.24"></a>
+<span class="sourceLineNo">025</span>import org.apache.hadoop.hbase.Cell;<a name="line.25"></a>
+<span class="sourceLineNo">026</span>import org.apache.hadoop.hbase.KeyValue;<a name="line.26"></a>
+<span class="sourceLineNo">027</span>import org.apache.hadoop.hbase.classification.InterfaceAudience;<a name="line.27"></a>
+<span class="sourceLineNo">028</span>import org.apache.hadoop.hbase.client.Scan;<a name="line.28"></a>
+<span class="sourceLineNo">029</span>import org.apache.htrace.Trace;<a name="line.29"></a>
+<span class="sourceLineNo">030</span><a name="line.30"></a>
+<span class="sourceLineNo">031</span>/**<a name="line.31"></a>
+<span class="sourceLineNo">032</span> * This is the scanner for any MemStore implementation, derived from MemStore.<a name="line.32"></a>
+<span class="sourceLineNo">033</span> * The MemStoreScanner combines SegmentScanner from different Segments and<a name="line.33"></a>
+<span class="sourceLineNo">034</span> * uses the key-value heap and the reversed key-value heap for the aggregated key-values set.<a name="line.34"></a>
+<span class="sourceLineNo">035</span> * It is assumed that only traversing forward or backward is used (without zigzagging in between)<a name="line.35"></a>
+<span class="sourceLineNo">036</span> */<a name="line.36"></a>
+<span class="sourceLineNo">037</span>@InterfaceAudience.Private<a name="line.37"></a>
+<span class="sourceLineNo">038</span>public class MemStoreScanner extends NonLazyKeyValueScanner {<a name="line.38"></a>
+<span class="sourceLineNo">039</span>  /**<a name="line.39"></a>
+<span class="sourceLineNo">040</span>   * Types of cell MemStoreScanner<a name="line.40"></a>
+<span class="sourceLineNo">041</span>   */<a name="line.41"></a>
+<span class="sourceLineNo">042</span>  static public enum Type {<a name="line.42"></a>
+<span class="sourceLineNo">043</span>    UNDEFINED,<a name="line.43"></a>
+<span class="sourceLineNo">044</span>    COMPACT_FORWARD,<a name="line.44"></a>
+<span class="sourceLineNo">045</span>    USER_SCAN_FORWARD,<a name="line.45"></a>
+<span class="sourceLineNo">046</span>    USER_SCAN_BACKWARD<a name="line.46"></a>
+<span class="sourceLineNo">047</span>  }<a name="line.47"></a>
+<span class="sourceLineNo">048</span><a name="line.48"></a>
+<span class="sourceLineNo">049</span>  // heap of scanners used for traversing forward<a name="line.49"></a>
+<span class="sourceLineNo">050</span>  private KeyValueHeap forwardHeap;<a name="line.50"></a>
+<span class="sourceLineNo">051</span>  // reversed scanners heap for traversing backward<a name="line.51"></a>
+<span class="sourceLineNo">052</span>  private ReversedKeyValueHeap backwardHeap;<a name="line.52"></a>
+<span class="sourceLineNo">053</span><a name="line.53"></a>
+<span class="sourceLineNo">054</span>  // The type of the scan is defined by constructor<a name="line.54"></a>
+<span class="sourceLineNo">055</span>  // or according to the first usage<a name="line.55"></a>
+<span class="sourceLineNo">056</span>  private Type type = Type.UNDEFINED;<a name="line.56"></a>
+<span class="sourceLineNo">057</span><a name="line.57"></a>
+<span class="sourceLineNo">058</span>  private long readPoint;<a name="line.58"></a>
+<span class="sourceLineNo">059</span>  // remember the initial version of the scanners list<a name="line.59"></a>
+<span class="sourceLineNo">060</span>  List&lt;SegmentScanner&gt; scanners;<a name="line.60"></a>
+<span class="sourceLineNo">061</span>  // pointer back to the relevant MemStore<a name="line.61"></a>
+<span class="sourceLineNo">062</span>  // is needed for shouldSeek() method<a name="line.62"></a>
+<span class="sourceLineNo">063</span>  private AbstractMemStore backwardReferenceToMemStore;<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>   * Constructor.<a name="line.66"></a>
+<span class="sourceLineNo">067</span>   * If UNDEFINED type for MemStoreScanner is provided, the forward heap is used as default!<a name="line.67"></a>
+<span class="sourceLineNo">068</span>   * After constructor only one heap is going to be initialized for entire lifespan<a name="line.68"></a>
+<span class="sourceLineNo">069</span>   * of the MemStoreScanner. A specific scanner can only be one directional!<a name="line.69"></a>
+<span class="sourceLineNo">070</span>   *<a name="line.70"></a>
+<span class="sourceLineNo">071</span>   * @param ms        Pointer back to the MemStore<a name="line.71"></a>
+<span class="sourceLineNo">072</span>   * @param readPoint Read point below which we can safely remove duplicate KVs<a name="line.72"></a>
+<span class="sourceLineNo">073</span>   * @param type      The scan type COMPACT_FORWARD should be used for compaction<a name="line.73"></a>
+<span class="sourceLineNo">074</span>   */<a name="line.74"></a>
+<span class="sourceLineNo">075</span>  public MemStoreScanner(AbstractMemStore ms, long readPoint, Type type) throws IOException {<a name="line.75"></a>
+<span class="sourceLineNo">076</span>    this(ms, ms.getListOfScanners(readPoint), readPoint, type);<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>  /* Constructor used only when the scan usage is unknown<a name="line.79"></a>
+<span class="sourceLineNo">080</span>  and need to be defined according to the first move */<a name="line.80"></a>
+<span class="sourceLineNo">081</span>  public MemStoreScanner(AbstractMemStore ms, long readPt) throws IOException {<a name="line.81"></a>
+<span class="sourceLineNo">082</span>    this(ms, readPt, Type.UNDEFINED);<a name="line.82"></a>
+<span class="sourceLineNo">083</span>  }<a name="line.83"></a>
+<span class="sourceLineNo">084</span><a name="line.84"></a>
+<span class="sourceLineNo">085</span>  public MemStoreScanner(AbstractMemStore ms, List&lt;SegmentScanner&gt; scanners, long readPoint,<a name="line.85"></a>
+<span class="sourceLineNo">086</span>      Type type) throws IOException {<a name="line.86"></a>
+<span class="sourceLineNo">087</span>    super();<a name="line.87"></a>
+<span class="sourceLineNo">088</span>    this.readPoint = readPoint;<a name="line.88"></a>
+<span class="sourceLineNo">089</span>    this.type = type;<a name="line.89"></a>
+<span class="sourceLineNo">090</span>    switch (type) {<a name="line.90"></a>
+<span class="sourceLineNo">091</span>      case UNDEFINED:<a name="line.91"></a>
+<span class="sourceLineNo">092</span>      case USER_SCAN_FORWARD:<a name="line.92"></a>
+<span class="sourceLineNo">093</span>      case COMPACT_FORWARD:<a name="line.93"></a>
+<span class="sourceLineNo">094</span>        this.forwardHeap = new KeyValueHeap(scanners, ms.getComparator());<a name="line.94"></a>
+<span class="sourceLineNo">095</span>        break;<a name="line.95"></a>
+<span class="sourceLineNo">096</span>      case USER_SCAN_BACKWARD:<a name="line.96"></a>
+<span class="sourceLineNo">097</span>        this.backwardHeap = new ReversedKeyValueHeap(scanners, ms.getComparator());<a name="line.97"></a>
+<span class="sourceLineNo">098</span>        break;<a name="line.98"></a>
+<span class="sourceLineNo">099</span>      default:<a name="line.99"></a>
+<span class="sourceLineNo">100</span>        throw new IllegalArgumentException("Unknown scanner type in MemStoreScanner");<a name="line.100"></a>
+<span class="sourceLineNo">101</span>    }<a name="line.101"></a>
+<span class="sourceLineNo">102</span>    this.backwardReferenceToMemStore = ms;<a name="line.102"></a>
+<span class="sourceLineNo">103</span>    this.scanners = scanners;<a name="line.103"></a>
+<span class="sourceLineNo">104</span>    if (Trace.isTracing() &amp;&amp; Trace.currentSpan() != null) {<a name="line.104"></a>
+<span class="sourceLineNo">105</span>      Trace.currentSpan().addTimelineAnnotation("Creating MemStoreScanner");<a name="line.105"></a>
+<span class="sourceLineNo">106</span>    }<a name="line.106"></a>
+<span class="sourceLineNo">107</span>  }<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>   * Returns the cell from the top-most scanner without advancing the iterator.<a name="line.110"></a>
+<span class="sourceLineNo">111</span>   * The backward traversal is assumed, only if specified explicitly<a name="line.111"></a>
+<span class="sourceLineNo">112</span>   */<a name="line.112"></a>
+<span class="sourceLineNo">113</span>  @Override<a name="line.113"></a>
+<span class="sourceLineNo">114</span>  public synchronized Cell peek() {<a name="line.114"></a>
+<span class="sourceLineNo">115</span>    if (type == Type.USER_SCAN_BACKWARD) {<a name="line.115"></a>
+<span class="sourceLineNo">116</span>      return backwardHeap.peek();<a name="line.116"></a>
+<span class="sourceLineNo">117</span>    }<a name="line.117"></a>
+<span class="sourceLineNo">118</span>    return forwardHeap.peek();<a name="line.118"></a>
+<span class="sourceLineNo">119</span>  }<a name="line.119"></a>
+<span class="sourceLineNo">120</span><a name="line.120"></a>
+<span class="sourceLineNo">121</span>  /**<a name="line.121"></a>
+<span class="sourceLineNo">122</span>   * Gets the next cell from the top-most scanner. Assumed forward scanning.<a name="line.122"></a>
+<span class="sourceLineNo">123</span>   */<a name="line.123"></a>
+<span class="sourceLineNo">124</span>  @Override<a name="line.124"></a>
+<span class="sourceLineNo">125</span>  public synchronized Cell next() throws IOException {<a name="line.125"></a>
+<span class="sourceLineNo">126</span>    KeyValueHeap heap = (Type.USER_SCAN_BACKWARD == type) ? backwardHeap : forwardHeap;<a name="line.126"></a>
+<span class="sourceLineNo">127</span><a name="line.127"></a>
+<span class="sourceLineNo">128</span>    // loop over till the next suitable value<a name="line.128"></a>
+<span class="sourceLineNo">129</span>    // take next value from the heap<a name="line.129"></a>
+<span class="sourceLineNo">130</span>    for (Cell currentCell = heap.next();<a name="line.130"></a>
+<span class="sourceLineNo">131</span>         currentCell != null;<a name="line.131"></a>
+<span class="sourceLineNo">132</span>         currentCell = heap.next()) {<a name="line.132"></a>
+<span class="sourceLineNo">133</span><a name="line.133"></a>
+<span class="sourceLineNo">134</span>      // all the logic of presenting cells is inside the internal SegmentScanners<a name="line.134"></a>
+<span class="sourceLineNo">135</span>      // located inside the heap<a name="line.135"></a>
+<span class="sourceLineNo">136</span><a name="line.136"></a>
+<span class="sourceLineNo">137</span>      return currentCell;<a name="line.137"></a>
+<span class="sourceLineNo">138</span>    }<a name="line.138"></a>
+<span class="sourceLineNo">139</span>    return null;<a name="line.139"></a>
+<span class="sourceLineNo">140</span>  }<a name="line.140"></a>
+<span class="sourceLineNo">141</span><a name="line.141"></a>
+<span class="sourceLineNo">142</span>  /**<a name="line.142"></a>
+<span class="sourceLineNo">143</span>   * Set the scanner at the seek key. Assumed forward scanning.<a name="line.143"></a>
+<span class="sourceLineNo">144</span>   * Must be called only once: there is no thread safety between the scanner<a name="line.144"></a>
+<span class="sourceLineNo">145</span>   * and the memStore.<a name="line.145"></a>
+<span class="sourceLineNo">146</span>   *<a name="line.146"></a>
+<span class="sourceLineNo">147</span>   * @param cell seek value<a name="line.147"></a>
+<span class="sourceLineNo">148</span>   * @return false if the key is null or if there is no data<a name="line.148"></a>
+<span class="sourceLineNo">149</span>   */<a name="line.149"></a>
+<span class="sourceLineNo">150</span>  @Override<a name="line.150"></a>
+<span class="sourceLineNo">151</span>  public synchronized boolean seek(Cell cell) throws IOException {<a name="line.151"></a>
+<span class="sourceLineNo">152</span>    assertForward();<a name="line.152"></a>
+<span class="sourceLineNo">153</span><a name="line.153"></a>
+<span class="sourceLineNo">154</span>    if (cell == null) {<a name="line.154"></a>
+<span class="sourceLineNo">155</span>      close();<a name="line.155"></a>
+<span class="sourceLineNo">156</span>      return false;<a name="line.156"></a>
+<span class="sourceLineNo">157</span>    }<a name="line.157"></a>
+<span class="sourceLineNo">158</span><a name="line.158"></a>
+<span class="sourceLineNo">159</span>    return forwardHeap.seek(cell);<a name="line.159"></a>
+<span class="sourceLineNo">160</span>  }<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>   * Move forward on the sub-lists set previously by seek. Assumed forward scanning.<a name="line.163"></a>
+<span class="sourceLineNo">164</span>   *<a name="line.164"></a>
+<span class="sourceLineNo">165</span>   * @param cell seek value (should be non-null)<a name="line.165"></a>
+<span class="sourceLineNo">166</span>   * @return true if there is at least one KV to read, false otherwise<a name="line.166"></a>
+<span class="sourceLineNo">167</span>   */<a name="line.167"></a>
+<span class="sourceLineNo">168</span>  @Override<a name="line.168"></a>
+<span class="sourceLineNo">169</span>  public synchronized boolean reseek(Cell cell) throws IOException {<a name="line.169"></a>
+<span class="sourceLineNo">170</span>    /*<a name="line.170"></a>
+<span class="sourceLineNo">171</span>    * See HBASE-4195 &amp; HBASE-3855 &amp; HBASE-6591 for the background on this implementation.<a name="line.171"></a>
+<span class="sourceLineNo">172</span>    * This code is executed concurrently with flush and puts, without locks.<a name="line.172"></a>
+<span class="sourceLineNo">173</span>    * Two points must be known when working on this code:<a name="line.173"></a>
+<span class="sourceLineNo">174</span>    * 1) It's not possible to use the 'kvTail' and 'snapshot'<a name="line.174"></a>
+<span class="sourceLineNo">175</span>    *  variables, as they are modified during a flush.<a name="line.175"></a>
+<span class="sourceLineNo">176</span>    * 2) The ideal implementation for performance would use the sub skip list<a name="line.176"></a>
+<span class="sourceLineNo">177</span>    *  implicitly pointed by the iterators 'kvsetIt' and<a name="line.177"></a>
+<span class="sourceLineNo">178</span>    *  'snapshotIt'. Unfortunately the Java API does not offer a method to<a name="line.178"></a>
+<span class="sourceLineNo">179</span>    *  get it. So we remember the last keys we iterated to and restore<a name="line.179"></a>
+<span class="sourceLineNo">180</span>    *  the reseeked set to at least that point.<a name="line.180"></a>
+<span class="sourceLineNo">181</span>    *<a name="line.181"></a>
+<span class="sourceLineNo">182</span>    *  TODO: The above comment copied from the original MemStoreScanner<a name="line.182"></a>
+<span class="sourceLineNo">183</span>    */<a name="line.183"></a>
+<span class="sourceLineNo">184</span>    assertForward();<a name="line.184"></a>
+<span class="sourceLineNo">185</span>    return forwardHeap.reseek(cell);<a name="line.185"></a>
+<span class="sourceLineNo">186</span>  }<a name="line.186"></a>
+<span class="sourceLineNo">187</span><a name="line.187"></a>
+<span class="sourceLineNo">188</span>  /**<a name="line.188"></a>
+<span class="sourceLineNo">189</span>   * MemStoreScanner returns max value as sequence id because it will<a name="line.189"></a>
+<span class="sourceLineNo">190</span>   * always have the latest data among all files.<a name="line.190"></a>
+<span class="sourceLineNo">191</span>   */<a name="line.191"></a>
+<span class="sourceLineNo">192</span>  @Override<a name="line.192"></a>
+<span class="sourceLineNo">193</span>  public synchronized long getSequenceID() {<a name="line.193"></a>
+<span class="sourceLineNo">194</span>    return Long.MAX_VALUE;<a name="line.194"></a>
+<span class="sourceLineNo">195</span>  }<a name="line.195"></a>
+<span class="sourceLineNo">196</span><a name="line.196"></a>
+<span class="sourceLineNo">197</span>  @Override<a name="line.197"></a>
+<span class="sourceLineNo">198</span>  public synchronized void close() {<a name="line.198"></a>
+<span class="sourceLineNo">199</span><a name="line.199"></a>
+<span class="sourceLineNo">200</span>    if (forwardHeap != null) {<a name="line.200"></a>
+<span class="sourceLineNo">201</span>      assert ((type == Type.USER_SCAN_FORWARD) ||<a name="line.201"></a>
+<span class="sourceLineNo">202</span>          (type == Type.COMPACT_FORWARD) || (type == Type.UNDEFINED));<a name="line.202"></a>
+<span class="sourceLineNo">203</span>      forwardHeap.close();<a name="line.203"></a>
+<span class="sourceLineNo">204</span>      forwardHeap = null;<a name="line.204"></a>
+<span class="sourceLineNo">205</span>      if (backwardHeap != null) {<a name="line.205"></a>
+<span class="sourceLineNo">206</span>        backwardHeap.close();<a name="line.206"></a>
+<span class="sourceLineNo">207</span>        backwardHeap = null;<a name="line.207"></a>
+<span class="sourceLineNo">208</span>      }<a name="line.208"></a>
+<span class="sourceLineNo">209</span>    } else if (backwardHeap != null) {<a name="line.209"></a>
+<span class="sourceLineNo">210</span>      assert (type == Type.USER_SCAN_BACKWARD);<a name="line.210"></a>
+<span class="sourceLineNo">211</span>      backwardHeap.close();<a name="line.211"></a>
+<span class="sourceLineNo">212</span>      backwardHeap = null;<a name="line.212"></a>
+<span class="sourceLineNo">213</span>    }<a name="line.213"></a>
+<span class="sourceLineNo">214</span>  }<a name="line.214"></a>
+<span class="sourceLineNo">215</span><a name="line.215"></a>
+<span class="sourceLineNo">216</span>  /**<a name="line.216"></a>
+<span class="sourceLineNo">217</span>   * Set the scanner at the seek key. Assumed backward scanning.<a name="line.217"></a>
+<span class="sourceLineNo">218</span>   *<a name="line.218"></a>
+<span class="sourceLineNo">219</span>   * @param cell seek value<a name="line.219"></a>
+<span class="sourceLineNo">220</span>   * @return false if the key is null or if there is no data<a name="line.220"></a>
+<span class="sourceLineNo">221</span>   */<a name="line.221"></a>
+<span class="sourceLineNo">222</span>  @Override<a name="line.222"></a>
+<span class="sourceLineNo">223</span>  public synchronized boolean backwardSeek(Cell cell) throws IOException {<a name="line.223"></a>
+<span class="sourceLineNo">224</span>    initBackwardHeapIfNeeded(cell, false);<a name="line.224"></a>
+<span class="sourceLineNo">225</span>    return backwardHeap.backwardSeek(cell);<a name="line.225"></a>
+<span class="sourceLineNo">226</span>  }<a name="line.226"></a>
+<span class="sourceLineNo">227</span><a name="line.227"></a>
+<span class="sourceLineNo">228</span>  /**<a name="line.228"></a>
+<span class="sourceLineNo">229</span>   * Assumed backward scanning.<a name="line.229"></a>
+<span class="sourceLineNo">230</span>   *<a name="line.230"></a>
+<span class="sourceLineNo">231</span>   * @param cell seek value<a name="line.231"></a>
+<span class="sourceLineNo">232</span>   * @return false if the key is null or if there is no data<a name="line.232"></a>
+<span class="sourceLineNo">233</span>   */<a name="line.233"></a>
+<span class="sourceLineNo">234</span>  @Override<a name="line.234"></a>
+<span class="sourceLineNo">235</span>  public synchronized boolean seekToPreviousRow(Cell cell) throws IOException {<a name="line.235"></a>
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+<span class="sourceLineNo">242</span><a name="line.242"></a>
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+<span class="sourceLineNo">244</span>  public synchronized boolean seekToLastRow() throws IOException {<a name="line.244"></a>
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+<span class="sourceLineNo">247</span>    // however seekToLastRow() was implemented in internal MemStoreScanner<a name="line.247"></a>
+<span class="sourceLineNo">248</span>    // so I wonder whether we need to come with our own workaround, or to update<a name="line.248"></a>
+<span class="sourceLineNo">249</span>    // ReversedKeyValueHeap<a name="line.249"></a>
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+<span class="sourceLineNo">256</span>   */<a name="line.256"></a>
+<span class="sourceLineNo">257</span>  @Override<a name="line.257"></a>
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+<span class="sourceLineNo">264</span>    for (SegmentScanner sc : scanners) {<a name="line.264"></a>
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+<span class="sourceLineNo">271</span><a name="line.271"></a>
+<span class="sourceLineNo">272</span>  // debug method<a name="line.272"></a>
+<span class="sourceLineNo">273</span>  @Override<a name="line.273"></a>
+<span class="sourceLineNo">274</span>  public String toString() {<a name="line.274"></a>
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+<span class="sourceLineNo">283</span>  /****************** Private methods ******************/<a name="line.283"></a>
+<span class="sourceLineNo">284</span>  /**<a name="line.284"></a>
+<span class="sourceLineNo">285</span>   * Restructure the ended backward heap after rerunning a seekToPreviousRow()<a name="line.285"></a>
+<span class="sourceLineNo">286</span>   * on each scanner<a name="line.286"></a>
+<span class="sourceLineNo">287</span>   * @return false if given Cell does not exist in any scanner<a name="line.287"></a>
+<span class="sourceLineNo">288</span>   */<a name="line.288"></a>
+<span class="sourceLineNo">289</span>  private boolean restartBackwardHeap(Cell cell) throws IOException {<a name="line.289"></a>
+<span class="sourceLineNo">290</span>    boolean res = false;<a name="line.290"></a>
+<span class="sourceLineNo">291</span>    for (SegmentScanner scan : scanners) {<a name="line.291"></a>
+<span class="sourceLineNo">292</span>      res |= scan.seekToPreviousRow(cell);<a name="line.292"></a>
+<span class="sourceLineNo">293</span>    }<a name="line.293"></a>
+<span class="sourceLineNo">294</span>    this.backwardHeap =<a name="line.294"></a>
+<span class="sourceLineNo">295</span>        new ReversedKeyValueHeap(scanners, backwardReferenceToMemStore.getComparator());<a name="line.295"></a>
+<span class="sourceLineNo">296</span>    return res;<a name="line.296"></a>
+<span class="sourceLineNo">297</span>  }<a name="line.297"></a>
+<span class="sourceLineNo">298</span><a name="line.298"></a>
+<span class="sourceLineNo">299</span>  /**<a name="line.299"></a>
+<span class="sourceLineNo">300</span>   * Checks whether the type of the scan suits the assumption of moving backward<a name="line.300"></a>
+<span class="sourceLineNo">301</span>   */<a name="line.301"></a>
+<span class="sourceLineNo">302</span>  private boolean initBackwardHeapIfNeeded(Cell cell, boolean toLast) throws IOException {<a name="line.302"></a>
+<span class="sourceLineNo">303</span>    boolean res = false;<a name="line.303"></a>
+<span class="sourceLineNo">304</span>    if (toLast &amp;&amp; (type != Type.UNDEFINED)) {<a name="line.304"></a>
+<span class="sourceLineNo">305</span>      throw new IllegalStateException(<a name="line.305"></a>
+<span class="sourceLineNo">306</span>          "Wrong usage of initBackwardHeapIfNeeded in parameters. The type is:" + type.toString());<a name="line.306"></a>
+<span class="sourceLineNo">307</span>    }<a name="line.307"></a>
+<span class="sourceLineNo">308</span>    if (type == Type.UNDEFINED) {<a name="line.308"></a>
+<span class="sourceLineNo">309</span>      // In case we started from peek, release the forward heap<a name="line.309"></a>
+<span class="sourceLineNo">310</span>      // and build backward. Set the correct type. Thus this turn<a name="line.310"></a>
+<span class="sourceLineNo">311</span>      // can happen only once<a name="line.311"></a>
+<span class="sourceLineNo">312</span>      if ((backwardHeap == null) &amp;&amp; (forwardHeap != null)) {<a name="line.312"></a>
+<span class="sourceLineNo">313</span>        forwardHeap.close();<a name="line.313"></a>
+<span class="sourceLineNo">314</span>        forwardHeap = null;<a name="line.314"></a>
+<span class="sourceLineNo">315</span>        // before building the heap seek for the relevant key on the scanners,<a name="line.315"></a>
+<span class="sourceLineNo">316</span>        // for the heap to be built from the scanners correctly<a name="line.316"></a>
+<span class="sourceLineNo">317</span>        for (SegmentScanner scan : scanners) {<a name="line.317"></a>
+<span class="sourceLineNo">318</span>          if (toLast) {<a name="line.318"></a>
+<span class="sourceLineNo">319</span>            res |= scan.seekToLastRow();<a name="line.319"></a>
+<span class="sourceLineNo">320</span>          } else {<a name="line.320"></a>
+<span class="sourceLineNo">321</span>            res |= scan.backwardSeek(cell);<a name="line.321"></a>
+<span class="sourceLineNo">322</span>          }<a name="line.322"></a>
+<span class="sourceLineNo">323</span>        }<a name="line.323"></a>
+<span class="sourceLineNo">324</span>        this.backwardHeap =<a name="line.324"></a>
+<span class="sourceLineNo">325</span>            new ReversedKeyValueHeap(scanners, backwardReferenceToMemStore.getComparator());<a name="line.325"></a>
+<span class="sourceLineNo">326</span>        type = Type.USER_SCAN_BACKWARD;<a name="line.326"></a>
+<span class="sourceLineNo">327</span>      }<a name="line.327"></a>
+<span class="sourceLineNo">328</span>    }<a name="line.328"></a>
+<span class="sourceLineNo">329</span><a name="line.329"></a>
+<span class="sourceLineNo">330</span>    if (type == Type.USER_SCAN_FORWARD) {<a name="line.330"></a>
+<span class="sourceLineNo">331</span>      throw new IllegalStateException("Traversing backward with forward scan");<a name="line.331"></a>
+<span class="sourceLineNo">332</span>    }<a name="line.332"></a>
+<span class="sourceLineNo">333</span>    return res;<a name="line.333"></a>
+<span class="sourceLineNo">334</span>  }<a name="line.334"></a>
+<span class="sourceLineNo">335</span><a name="line.335"></a>
+<span class="sourceLineNo">336</span>  /**<a name="line.336"></a>
+<span class="sourceLineNo">337</span>   * Checks whether the type of the scan suits the assumption of moving forward<a name="line.337"></a>
+<span class="sourceLineNo">338</span>   */<a name="line.338"></a>
+<span class="sourceLineNo">339</span>  private void assertForward() throws IllegalStateException {<a name="line.339"></a>
+<span class="sourceLineNo">340</span>    if (type == Type.UNDEFINED) {<a name="line.340"></a>
+<span class="sourceLineNo">341</span>      type = Type.USER_SCAN_FORWARD;<a name="line.341"></a>
+<span class="sourceLineNo">342</span>    }<a name="line.342"></a>
+<span class="sourceLineNo">343</span><a name="line.343"></a>
+<span class="sourceLineNo">344</span>    if (type == Type.USER_SCAN_BACKWARD) {<a name="line.344"></a>
+<span class="sourceLineNo">345</span>      throw new IllegalStateException("Traversing forward with backward scan");<a name="line.345"></a>
+<span class="sourceLineNo">346</span>    }<a name="line.346"></a>
+<span class="sourceLineNo">347</span>  }<a name="line.347"></a>
+<span class="sourceLineNo">348</span>}<a name="line.348"></a>
+
+
+
+
+
+
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+
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+
+
+
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+
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+
+
+
+
+
+
+
+</pre>
+</div>
+</body>
+</html>

http://git-wip-us.apache.org/repos/asf/hbase-site/blob/526c7822/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MemStoreSnapshot.html
----------------------------------------------------------------------
diff --git a/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MemStoreSnapshot.html b/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MemStoreSnapshot.html
index 306f00c..80fafda 100644
--- a/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MemStoreSnapshot.html
+++ b/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MemStoreSnapshot.html
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+<span class="sourceLineNo">076</span>   */<a name="line.76"></a>
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http://git-wip-us.apache.org/repos/asf/hbase-site/blob/526c7822/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MutableCellSetSegment.html
----------------------------------------------------------------------
diff --git a/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MutableCellSetSegment.html b/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MutableCellSetSegment.html
new file mode 100644
index 0000000..c2e5abe
--- /dev/null
+++ b/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MutableCellSetSegment.html
@@ -0,0 +1,225 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html lang="en">
+<head>
+<title>Source code</title>
+<link rel="stylesheet" type="text/css" href="../../../../../../stylesheet.css" title="Style">
+</head>
+<body>
+<div class="sourceContainer">
+<pre><span class="sourceLineNo">001</span>/**<a name="line.1"></a>
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+<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.Iterator;<a name="line.21"></a>
+<span class="sourceLineNo">022</span>import java.util.SortedSet;<a name="line.22"></a>
+<span class="sourceLineNo">023</span><a name="line.23"></a>
+<span class="sourceLineNo">024</span>import org.apache.commons.logging.Log;<a name="line.24"></a>
+<span class="sourceLineNo">025</span>import org.apache.hadoop.hbase.Cell;<a name="line.25"></a>
+<span class="sourceLineNo">026</span>import org.apache.hadoop.hbase.CellComparator;<a name="line.26"></a>
+<span class="sourceLineNo">027</span>import org.apache.hadoop.hbase.classification.InterfaceAudience;<a name="line.27"></a>
+<span class="sourceLineNo">028</span><a name="line.28"></a>
+<span class="sourceLineNo">029</span>/**<a name="line.29"></a>
+<span class="sourceLineNo">030</span> * This mutable store segment encapsulates a mutable cell set and its respective memory allocation<a name="line.30"></a>
+<span class="sourceLineNo">031</span> * buffers (MSLAB).<a name="line.31"></a>
+<span class="sourceLineNo">032</span> */<a name="line.32"></a>
+<span class="sourceLineNo">033</span>@InterfaceAudience.Private<a name="line.33"></a>
+<span class="sourceLineNo">034</span>final class MutableCellSetSegment extends MutableSegment {<a name="line.34"></a>
+<span class="sourceLineNo">035</span><a name="line.35"></a>
+<span class="sourceLineNo">036</span>  private volatile CellSet cellSet;<a name="line.36"></a>
+<span class="sourceLineNo">037</span>  private final CellComparator comparator;<a name="line.37"></a>
+<span class="sourceLineNo">038</span><a name="line.38"></a>
+<span class="sourceLineNo">039</span>  // Instantiate objects only using factory<a name="line.39"></a>
+<span class="sourceLineNo">040</span>  MutableCellSetSegment(CellSet cellSet, MemStoreLAB memStoreLAB, long size,<a name="line.40"></a>
+<span class="sourceLineNo">041</span>      CellComparator comparator) {<a name="line.41"></a>
+<span class="sourceLineNo">042</span>    super(memStoreLAB, size);<a name="line.42"></a>
+<span class="sourceLineNo">043</span>    this.cellSet = cellSet;<a name="line.43"></a>
+<span class="sourceLineNo">044</span>    this.comparator = comparator;<a name="line.44"></a>
+<span class="sourceLineNo">045</span>  }<a name="line.45"></a>
+<span class="sourceLineNo">046</span><a name="line.46"></a>
+<span class="sourceLineNo">047</span>  @Override<a name="line.47"></a>
+<span class="sourceLineNo">048</span>  public SegmentScanner getSegmentScanner(long readPoint) {<a name="line.48"></a>
+<span class="sourceLineNo">049</span>    return new MutableCellSetSegmentScanner(this, readPoint);<a name="line.49"></a>
+<span class="sourceLineNo">050</span>  }<a name="line.50"></a>
+<span class="sourceLineNo">051</span><a name="line.51"></a>
+<span class="sourceLineNo">052</span>  @Override<a name="line.52"></a>
+<span class="sourceLineNo">053</span>  public boolean isEmpty() {<a name="line.53"></a>
+<span class="sourceLineNo">054</span>    return getCellSet().isEmpty();<a name="line.54"></a>
+<span class="sourceLineNo">055</span>  }<a name="line.55"></a>
+<span class="sourceLineNo">056</span><a name="line.56"></a>
+<span class="sourceLineNo">057</span>  @Override<a name="line.57"></a>
+<span class="sourceLineNo">058</span>  public int getCellsCount() {<a name="line.58"></a>
+<span class="sourceLineNo">059</span>    return getCellSet().size();<a name="line.59"></a>
+<span class="sourceLineNo">060</span>  }<a name="line.60"></a>
+<span class="sourceLineNo">061</span><a name="line.61"></a>
+<span class="sourceLineNo">062</span>  @Override<a name="line.62"></a>
+<span class="sourceLineNo">063</span>  public long add(Cell cell) {<a name="line.63"></a>
+<span class="sourceLineNo">064</span>    boolean succ = getCellSet().add(cell);<a name="line.64"></a>
+<span class="sourceLineNo">065</span>    long s = AbstractMemStore.heapSizeChange(cell, succ);<a name="line.65"></a>
+<span class="sourceLineNo">066</span>    updateMetaInfo(cell, s);<a name="line.66"></a>
+<span class="sourceLineNo">067</span>    // In no tags case this NoTagsKeyValue.getTagsLength() is a cheap call.<a name="line.67"></a>
+<span class="sourceLineNo">068</span>    // When we use ACL CP or Visibility CP which deals with Tags during<a name="line.68"></a>
+<span class="sourceLineNo">069</span>    // mutation, the TagRewriteCell.getTagsLength() is a cheaper call. We do not<a name="line.69"></a>
+<span class="sourceLineNo">070</span>    // parse the byte[] to identify the tags length.<a name="line.70"></a>
+<span class="sourceLineNo">071</span>    if(cell.getTagsLength() &gt; 0) {<a name="line.71"></a>
+<span class="sourceLineNo">072</span>      tagsPresent = true;<a name="line.72"></a>
+<span class="sourceLineNo">073</span>    }<a name="line.73"></a>
+<span class="sourceLineNo">074</span>    return s;<a name="line.74"></a>
+<span class="sourceLineNo">075</span>  }<a name="line.75"></a>
+<span class="sourceLineNo">076</span><a name="line.76"></a>
+<span class="sourceLineNo">077</span>  @Override<a name="line.77"></a>
+<span class="sourceLineNo">078</span>  public long rollback(Cell cell) {<a name="line.78"></a>
+<span class="sourceLineNo">079</span>    Cell found = get(cell);<a name="line.79"></a>
+<span class="sourceLineNo">080</span>    if (found != null &amp;&amp; found.getSequenceId() == cell.getSequenceId()) {<a name="line.80"></a>
+<span class="sourceLineNo">081</span>      long sz = AbstractMemStore.heapSizeChange(cell, true);<a name="line.81"></a>
+<span class="sourceLineNo">082</span>      remove(cell);<a name="line.82"></a>
+<span class="sourceLineNo">083</span>      incSize(-sz);<a name="line.83"></a>
+<span class="sourceLineNo">084</span>      return sz;<a name="line.84"></a>
+<span class="sourceLineNo">085</span>    }<a name="line.85"></a>
+<span class="sourceLineNo">086</span>    return 0;<a name="line.86"></a>
+<span class="sourceLineNo">087</span>  }<a name="line.87"></a>
+<span class="sourceLineNo">088</span><a name="line.88"></a>
+<span class="sourceLineNo">089</span>  @Override<a name="line.89"></a>
+<span class="sourceLineNo">090</span>  public Cell getFirstAfter(Cell cell) {<a name="line.90"></a>
+<span class="sourceLineNo">091</span>    SortedSet&lt;Cell&gt; snTailSet = tailSet(cell);<a name="line.91"></a>
+<span class="sourceLineNo">092</span>    if (!snTailSet.isEmpty()) {<a name="line.92"></a>
+<span class="sourceLineNo">093</span>      return snTailSet.first();<a name="line.93"></a>
+<span class="sourceLineNo">094</span>    }<a name="line.94"></a>
+<span class="sourceLineNo">095</span>    return null;<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>  @Override<a name="line.98"></a>
+<span class="sourceLineNo">099</span>  public void dump(Log log) {<a name="line.99"></a>
+<span class="sourceLineNo">100</span>    for (Cell cell: getCellSet()) {<a name="line.100"></a>
+<span class="sourceLineNo">101</span>      log.debug(cell);<a name="line.101"></a>
+<span class="sourceLineNo">102</span>    }<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>  public SortedSet&lt;Cell&gt; tailSet(Cell firstCell) {<a name="line.106"></a>
+<span class="sourceLineNo">107</span>    return getCellSet().tailSet(firstCell);<a name="line.107"></a>
+<span class="sourceLineNo">108</span>  }<a name="line.108"></a>
+<span class="sourceLineNo">109</span>  @Override<a name="line.109"></a>
+<span class="sourceLineNo">110</span>  public CellSet getCellSet() {<a name="line.110"></a>
+<span class="sourceLineNo">111</span>    return cellSet;<a name="line.111"></a>
+<span class="sourceLineNo">112</span>  }<a name="line.112"></a>
+<span class="sourceLineNo">113</span>  @Override<a name="line.113"></a>
+<span class="sourceLineNo">114</span>  public CellComparator getComparator() {<a name="line.114"></a>
+<span class="sourceLineNo">115</span>    return comparator;<a name="line.115"></a>
+<span class="sourceLineNo">116</span>  }<a name="line.116"></a>
+<span class="sourceLineNo">117</span><a name="line.117"></a>
+<span class="sourceLineNo">118</span>  //*** Methods for MemStoreSegmentsScanner<a name="line.118"></a>
+<span class="sourceLineNo">119</span>  public Cell last() {<a name="line.119"></a>
+<span class="sourceLineNo">120</span>    return getCellSet().last();<a name="line.120"></a>
+<span class="sourceLineNo">121</span>  }<a name="line.121"></a>
+<span class="sourceLineNo">122</span><a name="line.122"></a>
+<span class="sourceLineNo">123</span>  public Iterator&lt;Cell&gt; iterator() {<a name="line.123"></a>
+<span class="sourceLineNo">124</span>    return getCellSet().iterator();<a name="line.124"></a>
+<span class="sourceLineNo">125</span>  }<a name="line.125"></a>
+<span class="sourceLineNo">126</span><a name="line.126"></a>
+<span class="sourceLineNo">127</span>  public SortedSet&lt;Cell&gt; headSet(Cell firstKeyOnRow) {<a name="line.127"></a>
+<span class="sourceLineNo">128</span>    return getCellSet().headSet(firstKeyOnRow);<a name="line.128"></a>
+<span class="sourceLineNo">129</span>  }<a name="line.129"></a>
+<span class="sourceLineNo">130</span><a name="line.130"></a>
+<span class="sourceLineNo">131</span>  public int compare(Cell left, Cell right) {<a name="line.131"></a>
+<span class="sourceLineNo">132</span>    return getComparator().compare(left, right);<a name="line.132"></a>
+<span class="sourceLineNo">133</span>  }<a name="line.133"></a>
+<span class="sourceLineNo">134</span><a name="line.134"></a>
+<span class="sourceLineNo">135</span>  public int compareRows(Cell left, Cell right) {<a name="line.135"></a>
+<span class="sourceLineNo">136</span>    return getComparator().compareRows(left, right);<a name="line.136"></a>
+<span class="sourceLineNo">137</span>  }<a name="line.137"></a>
+<span class="sourceLineNo">138</span><a name="line.138"></a>
+<span class="sourceLineNo">139</span>  private Cell get(Cell cell) {<a name="line.139"></a>
+<span class="sourceLineNo">140</span>    return getCellSet().get(cell);<a name="line.140"></a>
+<span class="sourceLineNo">141</span>  }<a name="line.141"></a>
+<span class="sourceLineNo">142</span><a name="line.142"></a>
+<span class="sourceLineNo">143</span>  private boolean remove(Cell e) {<a name="line.143"></a>
+<span class="sourceLineNo">144</span>    return getCellSet().remove(e);<a name="line.144"></a>
+<span class="sourceLineNo">145</span>  }<a name="line.145"></a>
+<span class="sourceLineNo">146</span><a name="line.146"></a>
+<span class="sourceLineNo">147</span>  // methods for tests<a name="line.147"></a>
+<span class="sourceLineNo">148</span>  @Override<a name="line.148"></a>
+<span class="sourceLineNo">149</span>  Cell first() {<a name="line.149"></a>
+<span class="sourceLineNo">150</span>    return this.getCellSet().first();<a name="line.150"></a>
+<span class="sourceLineNo">151</span>  }<a name="line.151"></a>
+<span class="sourceLineNo">152</span><a name="line.152"></a>
+<span class="sourceLineNo">153</span>}<a name="line.153"></a>
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+</pre>
+</div>
+</body>
+</html>

http://git-wip-us.apache.org/repos/asf/hbase-site/blob/526c7822/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MutableCellSetSegmentScanner.html
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html lang="en">
+<head>
+<title>Source code</title>
+<link rel="stylesheet" type="text/css" href="../../../../../../stylesheet.css" title="Style">
+</head>
+<body>
+<div class="sourceContainer">
+<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.regionserver;<a name="line.18"></a>
+<span class="sourceLineNo">019</span><a name="line.19"></a>
+<span class="sourceLineNo">020</span>import java.io.IOException;<a name="line.20"></a>
+<span class="sourceLineNo">021</span>import java.util.Iterator;<a name="line.21"></a>
+<span class="sourceLineNo">022</span>import java.util.SortedSet;<a name="line.22"></a>
+<span class="sourceLineNo">023</span><a name="line.23"></a>
+<span class="sourceLineNo">024</span>import org.apache.hadoop.hbase.Cell;<a name="line.24"></a>
+<span class="sourceLineNo">025</span>import org.apache.hadoop.hbase.CellUtil;<a name="line.25"></a>
+<span class="sourceLineNo">026</span>import org.apache.hadoop.hbase.classification.InterfaceAudience;<a name="line.26"></a>
+<span class="sourceLineNo">027</span><a name="line.27"></a>
+<span class="sourceLineNo">028</span>/**<a name="line.28"></a>
+<span class="sourceLineNo">029</span> * A scanner of a single cells segment {@link MutableCellSetSegment}.<a name="line.29"></a>
+<span class="sourceLineNo">030</span> */<a name="line.30"></a>
+<span class="sourceLineNo">031</span>@InterfaceAudience.Private<a name="line.31"></a>
+<span class="sourceLineNo">032</span>class MutableCellSetSegmentScanner extends SegmentScanner {<a name="line.32"></a>
+<span class="sourceLineNo">033</span><a name="line.33"></a>
+<span class="sourceLineNo">034</span>  // the observed structure<a name="line.34"></a>
+<span class="sourceLineNo">035</span>  private final MutableCellSetSegment segment;<a name="line.35"></a>
+<span class="sourceLineNo">036</span>  // the highest relevant MVCC<a name="line.36"></a>
+<span class="sourceLineNo">037</span>  private long readPoint;<a name="line.37"></a>
+<span class="sourceLineNo">038</span>  // the current iterator that can be reinitialized by<a name="line.38"></a>
+<span class="sourceLineNo">039</span>  // seek(), backwardSeek(), or reseek()<a name="line.39"></a>
+<span class="sourceLineNo">040</span>  private Iterator&lt;Cell&gt; iter;<a name="line.40"></a>
+<span class="sourceLineNo">041</span>  // the pre-calculated cell to be returned by peek()<a name="line.41"></a>
+<span class="sourceLineNo">042</span>  private Cell current = null;<a name="line.42"></a>
+<span class="sourceLineNo">043</span>  // or next()<a name="line.43"></a>
+<span class="sourceLineNo">044</span>  // A flag represents whether could stop skipping KeyValues for MVCC<a name="line.44"></a>
+<span class="sourceLineNo">045</span>  // if have encountered the next row. Only used for reversed scan<a name="line.45"></a>
+<span class="sourceLineNo">046</span>  private boolean stopSkippingKVsIfNextRow = false;<a name="line.46"></a>
+<span class="sourceLineNo">047</span>  // last iterated KVs by seek (to restore the iterator state after reseek)<a name="line.47"></a>
+<span class="sourceLineNo">048</span>  private Cell last = null;<a name="line.48"></a>
+<span class="sourceLineNo">049</span><a name="line.49"></a>
+<span class="sourceLineNo">050</span>  public MutableCellSetSegmentScanner(MutableCellSetSegment segment, long readPoint) {<a name="line.50"></a>
+<span class="sourceLineNo">051</span>    super();<a name="line.51"></a>
+<span class="sourceLineNo">052</span>    this.segment = segment;<a name="line.52"></a>
+<span class="sourceLineNo">053</span>    this.readPoint = readPoint;<a name="line.53"></a>
+<span class="sourceLineNo">054</span>    iter = segment.iterator();<a name="line.54"></a>
+<span class="sourceLineNo">055</span>    // the initialization of the current is required for working with heap of SegmentScanners<a name="line.55"></a>
+<span class="sourceLineNo">056</span>    current = getNext();<a name="line.56"></a>
+<span class="sourceLineNo">057</span>    //increase the reference count so the underlying structure will not be de-allocated<a name="line.57"></a>
+<span class="sourceLineNo">058</span>    this.segment.incScannerCount();<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>  /**<a name="line.61"></a>
+<span class="sourceLineNo">062</span>   * Look at the next Cell in this scanner, but do not iterate the scanner<a name="line.62"></a>
+<span class="sourceLineNo">063</span>   * @return the currently observed Cell<a name="line.63"></a>
+<span class="sourceLineNo">064</span>   */<a name="line.64"></a>
+<span class="sourceLineNo">065</span>  @Override<a name="line.65"></a>
+<span class="sourceLineNo">066</span>  public Cell peek() {          // sanity check, the current should be always valid<a name="line.66"></a>
+<span class="sourceLineNo">067</span>    if (current!=null &amp;&amp; current.getSequenceId() &gt; readPoint) {<a name="line.67"></a>
+<span class="sourceLineNo">068</span>      throw new RuntimeException("current is invalid: read point is "+readPoint+", " +<a name="line.68"></a>
+<span class="sourceLineNo">069</span>          "while current sequence id is " +current.getSequenceId());<a name="line.69"></a>
+<span class="sourceLineNo">070</span>    }<a name="line.70"></a>
+<span class="sourceLineNo">071</span><a name="line.71"></a>
+<span class="sourceLineNo">072</span>    return current;<a name="line.72"></a>
+<span class="sourceLineNo">073</span>  }<a name="line.73"></a>
+<span class="sourceLineNo">074</span><a name="line.74"></a>
+<span class="sourceLineNo">075</span>  /**<a name="line.75"></a>
+<span class="sourceLineNo">076</span>   * Return the next Cell in this scanner, iterating the scanner<a name="line.76"></a>
+<span class="sourceLineNo">077</span>   * @return the next Cell or null if end of scanner<a name="line.77"></a>
+<span class="sourceLineNo">078</span>   */<a name="line.78"></a>
+<span class="sourceLineNo">079</span>  @Override<a name="line.79"></a>
+<span class="sourceLineNo">080</span>  public Cell next() throws IOException {<a name="line.80"></a>
+<span class="sourceLineNo">081</span>    Cell oldCurrent = current;<a name="line.81"></a>
+<span class="sourceLineNo">082</span>    current = getNext();                  // update the currently observed Cell<a name="line.82"></a>
+<span class="sourceLineNo">083</span>    return oldCurrent;<a name="line.83"></a>
+<span class="sourceLineNo">084</span>  }<a name="line.84"></a>
+<span class="sourceLineNo">085</span><a name="line.85"></a>
+<span class="sourceLineNo">086</span>  /**<a name="line.86"></a>
+<span class="sourceLineNo">087</span>   * Seek the scanner at or after the specified Cell.<a name="line.87"></a>
+<span class="sourceLineNo">088</span>   * @param cell seek value<a name="line.88"></a>
+<span class="sourceLineNo">089</span>   * @return true if scanner has values left, false if end of scanner<a name="line.89"></a>
+<span class="sourceLineNo">090</span>   */<a name="line.90"></a>
+<span class="sourceLineNo">091</span>  @Override<a name="line.91"></a>
+<span class="sourceLineNo">092</span>  public boolean seek(Cell cell) throws IOException {<a name="line.92"></a>
+<span class="sourceLineNo">093</span>    if(cell == null) {<a name="line.93"></a>
+<span class="sourceLineNo">094</span>      close();<a name="line.94"></a>
+<span class="sourceLineNo">095</span>      return false;<a name="line.95"></a>
+<span class="sourceLineNo">096</span>    }<a name="line.96"></a>
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+<span class="sourceLineNo">186</span>  /**<a name="line.186"></a>
+<span class="sourceLineNo">187</span>   * Seek the scanner at the first KeyValue of last row<a name="line.187"></a>
+<span class="sourceLineNo">188</span>   *<a name="line.188"></a>
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+<span class="sourceLineNo">212</span><a name="line.212"></a>
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+<span class="sourceLineNo">214</span>   * Private internal method for iterating over the segment,<a name="line.214"></a>
+<span class="sourceLineNo">215</span>   * skipping the cells with irrelevant MVCC<a name="line.215"></a>
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+<span class="sourceLineNo">234</span>      return null; // nothing found<a name="line.234"></a>
+<span class="sourceLineNo">235</span>    } finally {<a name="line.235"></a>
+<span class="sourceLineNo">236</span>      if (next != null) {<a name="line.236"></a>
+<span class="sourceLineNo">237</span>        // in all cases, remember the last KV we iterated to, needed for reseek()<a name="line.237"></a>
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+<span class="sourceLineNo">240</span>    }<a name="line.240"></a>
+<span class="sourceLineNo">241</span>  }<a name="line.241"></a>
+<span class="sourceLineNo">242</span><a name="line.242"></a>
+<span class="sourceLineNo">243</span>  /**<a name="line.243"></a>
+<span class="sourceLineNo">244</span>   * Private internal method that returns the higher of the two key values, or null<a name="line.244"></a>
+<span class="sourceLineNo">245</span>   * if they are both null<a name="line.245"></a>
+<span class="sourceLineNo">246</span>   */<a name="line.246"></a>
+<span class="sourceLineNo">247</span>  private Cell getHighest(Cell first, Cell second) {<a name="line.247"></a>
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+</pre>
+</div>
+</body>
+</html>

http://git-wip-us.apache.org/repos/asf/hbase-site/blob/526c7822/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/MutableSegment.html
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+<html lang="en">
+<head>
+<title>Source code</title>
+<link rel="stylesheet" type="text/css" href="../../../../../../stylesheet.css" title="Style">
+</head>
+<body>
+<div class="sourceContainer">
+<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.SortedSet;<a name="line.21"></a>
+<span class="sourceLineNo">022</span><a name="line.22"></a>
+<span class="sourceLineNo">023</span>import org.apache.hadoop.hbase.Cell;<a name="line.23"></a>
+<span class="sourceLineNo">024</span>import org.apache.hadoop.hbase.CellComparator;<a name="line.24"></a>
+<span class="sourceLineNo">025</span>import org.apache.hadoop.hbase.classification.InterfaceAudience;<a name="line.25"></a>
+<span class="sourceLineNo">026</span><a name="line.26"></a>
+<span class="sourceLineNo">027</span>/**<a name="line.27"></a>
+<span class="sourceLineNo">028</span> * An abstraction of a mutable segment in memstore, specifically the active segment.<a name="line.28"></a>
+<span class="sourceLineNo">029</span> */<a name="line.29"></a>
+<span class="sourceLineNo">030</span>@InterfaceAudience.Private<a name="line.30"></a>
+<span class="sourceLineNo">031</span>public abstract class MutableSegment extends Segment {<a name="line.31"></a>
+<span class="sourceLineNo">032</span><a name="line.32"></a>
+<span class="sourceLineNo">033</span>  protected MutableSegment(MemStoreLAB memStoreLAB, long size) {<a name="line.33"></a>
+<span class="sourceLineNo">034</span>    super(memStoreLAB, size);<a name="line.34"></a>
+<span class="sourceLineNo">035</span>  }<a name="line.35"></a>
+<span class="sourceLineNo">036</span><a name="line.36"></a>
+<span class="sourceLineNo">037</span>  /**<a name="line.37"></a>
+<span class="sourceLineNo">038</span>   * Returns a subset of the segment cell set, which starts with the given cell<a name="line.38"></a>
+<span class="sourceLineNo">039</span>   * @param firstCell a cell in the segment<a name="line.39"></a>
+<span class="sourceLineNo">040</span>   * @return a subset of the segment cell set, which starts with the given cell<a name="line.40"></a>
+<span class="sourceLineNo">041</span>   */<a name="line.41"></a>
+<span class="sourceLineNo">042</span>  public abstract SortedSet&lt;Cell&gt; tailSet(Cell firstCell);<a name="line.42"></a>
+<span class="sourceLineNo">043</span><a name="line.43"></a>
+<span class="sourceLineNo">044</span>  /**<a name="line.44"></a>
+<span class="sourceLineNo">045</span>   * Returns the Cell comparator used by this segment<a name="line.45"></a>
+<span class="sourceLineNo">046</span>   * @return the Cell comparator used by this segment<a name="line.46"></a>
+<span class="sourceLineNo">047</span>   */<a name="line.47"></a>
+<span class="sourceLineNo">048</span>  public abstract CellComparator getComparator();<a name="line.48"></a>
+<span class="sourceLineNo">049</span><a name="line.49"></a>
+<span class="sourceLineNo">050</span>  //methods for test<a name="line.50"></a>
+<span class="sourceLineNo">051</span><a name="line.51"></a>
+<span class="sourceLineNo">052</span>  /**<a name="line.52"></a>
+<span class="sourceLineNo">053</span>   * Returns the first cell in the segment<a name="line.53"></a>
+<span class="sourceLineNo">054</span>   * @return the first cell in the segment<a name="line.54"></a>
+<span class="sourceLineNo">055</span>   */<a name="line.55"></a>
+<span class="sourceLineNo">056</span>  abstract Cell first();<a name="line.56"></a>
+<span class="sourceLineNo">057</span>}<a name="line.57"></a>
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+</pre>
+</div>
+</body>
+</html>