http://git-wip-us.apache.org/repos/asf/hbase-site/blob/1241ee85/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/SegmentScanner.html
----------------------------------------------------------------------
diff --git
a/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/SegmentScanner.html
b/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/SegmentScanner.html
index 11e5e0a..bb27967 100644
---
a/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/SegmentScanner.html
+++
b/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/SegmentScanner.html
@@ -31,381 +31,386 @@
<span class="sourceLineNo">023</span>import java.util.SortedSet;<a
name="line.23"></a>
<span class="sourceLineNo">024</span><a name="line.24"></a>
<span class="sourceLineNo">025</span>import
org.apache.commons.lang.NotImplementedException;<a name="line.25"></a>
-<span class="sourceLineNo">026</span>import org.apache.hadoop.hbase.Cell;<a
name="line.26"></a>
-<span class="sourceLineNo">027</span>import
org.apache.hadoop.hbase.CellUtil;<a name="line.27"></a>
-<span class="sourceLineNo">028</span>import
org.apache.hadoop.hbase.classification.InterfaceAudience;<a name="line.28"></a>
-<span class="sourceLineNo">029</span>import
org.apache.hadoop.hbase.client.Scan;<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> * A scanner of a single memstore
segment.<a name="line.32"></a>
-<span class="sourceLineNo">033</span> */<a name="line.33"></a>
-<span class="sourceLineNo">034</span>@InterfaceAudience.Private<a
name="line.34"></a>
-<span class="sourceLineNo">035</span>public class SegmentScanner implements
KeyValueScanner {<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> * Order of this scanner relative to
other scanners. See<a name="line.38"></a>
-<span class="sourceLineNo">039</span> * {@link
KeyValueScanner#getScannerOrder()}.<a name="line.39"></a>
-<span class="sourceLineNo">040</span> */<a name="line.40"></a>
-<span class="sourceLineNo">041</span> private long scannerOrder;<a
name="line.41"></a>
-<span class="sourceLineNo">042</span> private static final long
DEFAULT_SCANNER_ORDER = Long.MAX_VALUE;<a name="line.42"></a>
-<span class="sourceLineNo">043</span><a name="line.43"></a>
-<span class="sourceLineNo">044</span> // the observed structure<a
name="line.44"></a>
-<span class="sourceLineNo">045</span> protected final Segment segment;<a
name="line.45"></a>
-<span class="sourceLineNo">046</span> // the highest relevant MVCC<a
name="line.46"></a>
-<span class="sourceLineNo">047</span> private long readPoint;<a
name="line.47"></a>
-<span class="sourceLineNo">048</span> // the current iterator that can be
reinitialized by<a name="line.48"></a>
-<span class="sourceLineNo">049</span> // seek(), backwardSeek(), or
reseek()<a name="line.49"></a>
-<span class="sourceLineNo">050</span> protected Iterator<Cell> iter;<a
name="line.50"></a>
-<span class="sourceLineNo">051</span> // the pre-calculated cell to be
returned by peek()<a name="line.51"></a>
-<span class="sourceLineNo">052</span> protected Cell current = null;<a
name="line.52"></a>
-<span class="sourceLineNo">053</span> // or next()<a name="line.53"></a>
-<span class="sourceLineNo">054</span> // A flag represents whether could stop
skipping KeyValues for MVCC<a name="line.54"></a>
-<span class="sourceLineNo">055</span> // if have encountered the next row.
Only used for reversed scan<a name="line.55"></a>
-<span class="sourceLineNo">056</span> private boolean
stopSkippingKVsIfNextRow = false;<a name="line.56"></a>
-<span class="sourceLineNo">057</span> // last iterated KVs by seek (to
restore the iterator state after reseek)<a name="line.57"></a>
-<span class="sourceLineNo">058</span> private Cell last = null;<a
name="line.58"></a>
-<span class="sourceLineNo">059</span><a name="line.59"></a>
-<span class="sourceLineNo">060</span> // flag to indicate if this scanner is
closed<a name="line.60"></a>
-<span class="sourceLineNo">061</span> protected boolean closed = false;<a
name="line.61"></a>
-<span class="sourceLineNo">062</span><a name="line.62"></a>
-<span class="sourceLineNo">063</span> protected SegmentScanner(Segment
segment, long readPoint) {<a name="line.63"></a>
-<span class="sourceLineNo">064</span> this(segment, readPoint,
DEFAULT_SCANNER_ORDER);<a name="line.64"></a>
-<span class="sourceLineNo">065</span> }<a name="line.65"></a>
-<span class="sourceLineNo">066</span><a name="line.66"></a>
-<span class="sourceLineNo">067</span> /**<a name="line.67"></a>
-<span class="sourceLineNo">068</span> * @param scannerOrder see {@link
KeyValueScanner#getScannerOrder()}.<a name="line.68"></a>
-<span class="sourceLineNo">069</span> * Scanners are ordered from 0 (oldest)
to newest in increasing order.<a name="line.69"></a>
-<span class="sourceLineNo">070</span> */<a name="line.70"></a>
-<span class="sourceLineNo">071</span> protected SegmentScanner(Segment
segment, long readPoint, long scannerOrder) {<a name="line.71"></a>
-<span class="sourceLineNo">072</span> this.segment = segment;<a
name="line.72"></a>
-<span class="sourceLineNo">073</span> this.readPoint = readPoint;<a
name="line.73"></a>
-<span class="sourceLineNo">074</span> //increase the reference count so the
underlying structure will not be de-allocated<a name="line.74"></a>
-<span class="sourceLineNo">075</span> this.segment.incScannerCount();<a
name="line.75"></a>
-<span class="sourceLineNo">076</span> iter = segment.iterator();<a
name="line.76"></a>
-<span class="sourceLineNo">077</span> // the initialization of the current
is required for working with heap of SegmentScanners<a name="line.77"></a>
-<span class="sourceLineNo">078</span> updateCurrent();<a name="line.78"></a>
-<span class="sourceLineNo">079</span> this.scannerOrder = scannerOrder;<a
name="line.79"></a>
-<span class="sourceLineNo">080</span> if (current == null) {<a
name="line.80"></a>
-<span class="sourceLineNo">081</span> // nothing to fetch from this
scanner<a name="line.81"></a>
-<span class="sourceLineNo">082</span> close();<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><a name="line.85"></a>
-<span class="sourceLineNo">086</span> /**<a name="line.86"></a>
-<span class="sourceLineNo">087</span> * Look at the next Cell in this
scanner, but do not iterate the scanner<a name="line.87"></a>
-<span class="sourceLineNo">088</span> * @return the currently observed
Cell<a name="line.88"></a>
-<span class="sourceLineNo">089</span> */<a name="line.89"></a>
-<span class="sourceLineNo">090</span> @Override<a name="line.90"></a>
-<span class="sourceLineNo">091</span> public Cell peek() { // sanity
check, the current should be always valid<a name="line.91"></a>
-<span class="sourceLineNo">092</span> if (closed) {<a name="line.92"></a>
-<span class="sourceLineNo">093</span> return null;<a name="line.93"></a>
-<span class="sourceLineNo">094</span> }<a name="line.94"></a>
-<span class="sourceLineNo">095</span> if (current!=null &&
current.getSequenceId() > readPoint) {<a name="line.95"></a>
-<span class="sourceLineNo">096</span> throw new RuntimeException("current
is invalid: read point is "+readPoint+", " +<a name="line.96"></a>
-<span class="sourceLineNo">097</span> "while current sequence id is "
+current.getSequenceId());<a name="line.97"></a>
-<span class="sourceLineNo">098</span> }<a name="line.98"></a>
-<span class="sourceLineNo">099</span> return current;<a name="line.99"></a>
-<span class="sourceLineNo">100</span> }<a name="line.100"></a>
-<span class="sourceLineNo">101</span><a name="line.101"></a>
-<span class="sourceLineNo">102</span> /**<a name="line.102"></a>
-<span class="sourceLineNo">103</span> * Return the next Cell in this
scanner, iterating the scanner<a name="line.103"></a>
-<span class="sourceLineNo">104</span> * @return the next Cell or null if end
of scanner<a name="line.104"></a>
-<span class="sourceLineNo">105</span> */<a name="line.105"></a>
-<span class="sourceLineNo">106</span> @Override<a name="line.106"></a>
-<span class="sourceLineNo">107</span> public Cell next() throws IOException
{<a name="line.107"></a>
-<span class="sourceLineNo">108</span> if (closed) {<a name="line.108"></a>
-<span class="sourceLineNo">109</span> return null;<a name="line.109"></a>
-<span class="sourceLineNo">110</span> }<a name="line.110"></a>
-<span class="sourceLineNo">111</span> Cell oldCurrent = current;<a
name="line.111"></a>
-<span class="sourceLineNo">112</span> updateCurrent(); //
update the currently observed Cell<a name="line.112"></a>
-<span class="sourceLineNo">113</span> return oldCurrent;<a
name="line.113"></a>
-<span class="sourceLineNo">114</span> }<a name="line.114"></a>
-<span class="sourceLineNo">115</span><a name="line.115"></a>
-<span class="sourceLineNo">116</span> /**<a name="line.116"></a>
-<span class="sourceLineNo">117</span> * Seek the scanner at or after the
specified Cell.<a name="line.117"></a>
-<span class="sourceLineNo">118</span> * @param cell seek value<a
name="line.118"></a>
-<span class="sourceLineNo">119</span> * @return true if scanner has values
left, false if end of scanner<a name="line.119"></a>
-<span class="sourceLineNo">120</span> */<a name="line.120"></a>
-<span class="sourceLineNo">121</span> @Override<a name="line.121"></a>
-<span class="sourceLineNo">122</span> public boolean seek(Cell cell) throws
IOException {<a name="line.122"></a>
-<span class="sourceLineNo">123</span> if (closed) {<a name="line.123"></a>
-<span class="sourceLineNo">124</span> return false;<a name="line.124"></a>
-<span class="sourceLineNo">125</span> }<a name="line.125"></a>
-<span class="sourceLineNo">126</span> if(cell == null) {<a
name="line.126"></a>
-<span class="sourceLineNo">127</span> close();<a name="line.127"></a>
-<span class="sourceLineNo">128</span> return false;<a name="line.128"></a>
-<span class="sourceLineNo">129</span> }<a name="line.129"></a>
-<span class="sourceLineNo">130</span> // restart the iterator from new
key<a name="line.130"></a>
-<span class="sourceLineNo">131</span> iter = getIterator(cell);<a
name="line.131"></a>
-<span class="sourceLineNo">132</span> // last is going to be reinitialized
in the next getNext() call<a name="line.132"></a>
-<span class="sourceLineNo">133</span> last = null;<a name="line.133"></a>
-<span class="sourceLineNo">134</span> updateCurrent();<a
name="line.134"></a>
-<span class="sourceLineNo">135</span> return (current != null);<a
name="line.135"></a>
-<span class="sourceLineNo">136</span> }<a name="line.136"></a>
-<span class="sourceLineNo">137</span><a name="line.137"></a>
-<span class="sourceLineNo">138</span> protected Iterator<Cell>
getIterator(Cell cell) {<a name="line.138"></a>
-<span class="sourceLineNo">139</span> return
segment.tailSet(cell).iterator();<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> * Reseek the scanner at or after the
specified KeyValue.<a name="line.143"></a>
-<span class="sourceLineNo">144</span> * This method is guaranteed to seek at
or after the required key only if the<a name="line.144"></a>
-<span class="sourceLineNo">145</span> * key comes after the current position
of the scanner. Should not be used<a name="line.145"></a>
-<span class="sourceLineNo">146</span> * to seek to a key which may come
before the current position.<a name="line.146"></a>
-<span class="sourceLineNo">147</span> *<a name="line.147"></a>
-<span class="sourceLineNo">148</span> * @param cell seek value (should be
non-null)<a name="line.148"></a>
-<span class="sourceLineNo">149</span> * @return true if scanner has values
left, false if end of scanner<a name="line.149"></a>
-<span class="sourceLineNo">150</span> */<a name="line.150"></a>
-<span class="sourceLineNo">151</span> @Override<a name="line.151"></a>
-<span class="sourceLineNo">152</span> public boolean reseek(Cell cell) throws
IOException {<a name="line.152"></a>
-<span class="sourceLineNo">153</span> if (closed) {<a name="line.153"></a>
-<span class="sourceLineNo">154</span> return false;<a name="line.154"></a>
-<span class="sourceLineNo">155</span> }<a name="line.155"></a>
-<span class="sourceLineNo">156</span> /*<a name="line.156"></a>
-<span class="sourceLineNo">157</span> See HBASE-4195 & HBASE-3855 &
HBASE-6591 for the background on this implementation.<a name="line.157"></a>
-<span class="sourceLineNo">158</span> This code is executed concurrently
with flush and puts, without locks.<a name="line.158"></a>
-<span class="sourceLineNo">159</span> The ideal implementation for
performance would use the sub skip list implicitly<a name="line.159"></a>
-<span class="sourceLineNo">160</span> pointed by the iterator.
Unfortunately the Java API does not offer a method to<a name="line.160"></a>
-<span class="sourceLineNo">161</span> get it. So we remember the last keys
we iterated to and restore<a name="line.161"></a>
-<span class="sourceLineNo">162</span> the reseeked set to at least that
point.<a name="line.162"></a>
-<span class="sourceLineNo">163</span> */<a name="line.163"></a>
-<span class="sourceLineNo">164</span> iter = getIterator(getHighest(cell,
last));<a name="line.164"></a>
-<span class="sourceLineNo">165</span> updateCurrent();<a
name="line.165"></a>
-<span class="sourceLineNo">166</span> return (current != null);<a
name="line.166"></a>
-<span class="sourceLineNo">167</span> }<a name="line.167"></a>
-<span class="sourceLineNo">168</span><a name="line.168"></a>
-<span class="sourceLineNo">169</span> /**<a name="line.169"></a>
-<span class="sourceLineNo">170</span> * Seek the scanner at or before the
row of specified Cell, it firstly<a name="line.170"></a>
-<span class="sourceLineNo">171</span> * tries to seek the scanner at or
after the specified Cell, return if<a name="line.171"></a>
-<span class="sourceLineNo">172</span> * peek KeyValue of scanner has the
same row with specified Cell,<a name="line.172"></a>
-<span class="sourceLineNo">173</span> * otherwise seek the scanner at the
first Cell of the row which is the<a name="line.173"></a>
-<span class="sourceLineNo">174</span> * previous row of specified KeyValue<a
name="line.174"></a>
-<span class="sourceLineNo">175</span> *<a name="line.175"></a>
-<span class="sourceLineNo">176</span> * @param key seek Cell<a
name="line.176"></a>
-<span class="sourceLineNo">177</span> * @return true if the scanner is at
the valid KeyValue, false if such Cell does not exist<a name="line.177"></a>
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-<span class="sourceLineNo">179</span> @Override<a name="line.179"></a>
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throws IOException {<a name="line.180"></a>
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-<span class="sourceLineNo">182</span> return false;<a name="line.182"></a>
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-<span class="sourceLineNo">184</span> seek(key); // seek forward then go
backward<a name="line.184"></a>
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segment.compareRows(peek(), key) > 0) {<a name="line.185"></a>
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name="line.186"></a>
-<span class="sourceLineNo">187</span> }<a name="line.187"></a>
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-<span class="sourceLineNo">190</span><a name="line.190"></a>
-<span class="sourceLineNo">191</span> /**<a name="line.191"></a>
-<span class="sourceLineNo">192</span> * Seek the scanner at the first Cell
of the row which is the previous row<a name="line.192"></a>
-<span class="sourceLineNo">193</span> * of specified key<a
name="line.193"></a>
-<span class="sourceLineNo">194</span> *<a name="line.194"></a>
-<span class="sourceLineNo">195</span> * @param cell seek value<a
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first valid Cell of previous row,<a name="line.196"></a>
-<span class="sourceLineNo">197</span> * false if not existing such
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CellUtil.createFirstOnRow(key);<a name="line.207"></a>
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segment.headSet(firstKeyOnRow);<a name="line.208"></a>
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cellHead.isEmpty() ? null : cellHead.last();<a name="line.209"></a>
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name="line.212"></a>
-<span class="sourceLineNo">213</span> }<a name="line.213"></a>
-<span class="sourceLineNo">214</span> Cell firstKeyOnPreviousRow =
CellUtil.createFirstOnRow(lastCellBeforeRow);<a name="line.214"></a>
-<span class="sourceLineNo">215</span> this.stopSkippingKVsIfNextRow =
true;<a name="line.215"></a>
-<span class="sourceLineNo">216</span> seek(firstKeyOnPreviousRow);<a
name="line.216"></a>
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false;<a name="line.217"></a>
-<span class="sourceLineNo">218</span> if (peek() == null<a
name="line.218"></a>
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segment.getComparator().compareRows(peek(), firstKeyOnPreviousRow) > 0) {<a
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-<span class="sourceLineNo">221</span> key = firstKeyOnPreviousRow;<a
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-<span class="sourceLineNo">232</span> *<a name="line.232"></a>
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-<span class="sourceLineNo">247</span> if (seek(firstCellOnLastRow)) {<a
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seekToPreviousRow(higherCell);<a name="line.250"></a>
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-<span class="sourceLineNo">252</span> }<a name="line.252"></a>
-<span class="sourceLineNo">253</span><a name="line.253"></a>
-<span class="sourceLineNo">254</span> /**<a name="line.254"></a>
-<span class="sourceLineNo">255</span> * @see
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-<span class="sourceLineNo">262</span> /**<a name="line.262"></a>
-<span class="sourceLineNo">263</span> * Close the KeyValue scanner.<a
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-<span class="sourceLineNo">264</span> */<a name="line.264"></a>
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on scanners that always do real seek operations (i.e. most<a
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NotImplementedException("enforceSeek cannot be called on a SegmentScanner");<a
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(RPC) and set to be returned to client. Any in between<a name="line.330"></a>
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be done for MutableCellSetSegmentScanner.<a name="line.331"></a>
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IOException {<a name="line.334"></a>
-<span class="sourceLineNo">335</span> // do nothing<a name="line.335"></a>
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-<span class="sourceLineNo">337</span><a name="line.337"></a>
-<span class="sourceLineNo">338</span> //debug method<a name="line.338"></a>
+<span class="sourceLineNo">026</span>import org.apache.hadoop.fs.Path;<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.classification.InterfaceAudience;<a name="line.29"></a>
+<span class="sourceLineNo">030</span>import
org.apache.hadoop.hbase.client.Scan;<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 scanner of a single memstore
segment.<a name="line.33"></a>
+<span class="sourceLineNo">034</span> */<a name="line.34"></a>
+<span class="sourceLineNo">035</span>@InterfaceAudience.Private<a
name="line.35"></a>
+<span class="sourceLineNo">036</span>public class SegmentScanner implements
KeyValueScanner {<a name="line.36"></a>
+<span class="sourceLineNo">037</span><a name="line.37"></a>
+<span class="sourceLineNo">038</span> /**<a name="line.38"></a>
+<span class="sourceLineNo">039</span> * Order of this scanner relative to
other scanners. See<a name="line.39"></a>
+<span class="sourceLineNo">040</span> * {@link
KeyValueScanner#getScannerOrder()}.<a name="line.40"></a>
+<span class="sourceLineNo">041</span> */<a name="line.41"></a>
+<span class="sourceLineNo">042</span> private long scannerOrder;<a
name="line.42"></a>
+<span class="sourceLineNo">043</span> private static final long
DEFAULT_SCANNER_ORDER = Long.MAX_VALUE;<a name="line.43"></a>
+<span class="sourceLineNo">044</span><a name="line.44"></a>
+<span class="sourceLineNo">045</span> // the observed structure<a
name="line.45"></a>
+<span class="sourceLineNo">046</span> protected final Segment segment;<a
name="line.46"></a>
+<span class="sourceLineNo">047</span> // the highest relevant MVCC<a
name="line.47"></a>
+<span class="sourceLineNo">048</span> private long readPoint;<a
name="line.48"></a>
+<span class="sourceLineNo">049</span> // the current iterator that can be
reinitialized by<a name="line.49"></a>
+<span class="sourceLineNo">050</span> // seek(), backwardSeek(), or
reseek()<a name="line.50"></a>
+<span class="sourceLineNo">051</span> protected Iterator<Cell> iter;<a
name="line.51"></a>
+<span class="sourceLineNo">052</span> // the pre-calculated cell to be
returned by peek()<a name="line.52"></a>
+<span class="sourceLineNo">053</span> protected Cell current = null;<a
name="line.53"></a>
+<span class="sourceLineNo">054</span> // or next()<a name="line.54"></a>
+<span class="sourceLineNo">055</span> // A flag represents whether could stop
skipping KeyValues for MVCC<a name="line.55"></a>
+<span class="sourceLineNo">056</span> // if have encountered the next row.
Only used for reversed scan<a name="line.56"></a>
+<span class="sourceLineNo">057</span> private boolean
stopSkippingKVsIfNextRow = false;<a name="line.57"></a>
+<span class="sourceLineNo">058</span> // last iterated KVs by seek (to
restore the iterator state after reseek)<a name="line.58"></a>
+<span class="sourceLineNo">059</span> private Cell last = null;<a
name="line.59"></a>
+<span class="sourceLineNo">060</span><a name="line.60"></a>
+<span class="sourceLineNo">061</span> // flag to indicate if this scanner is
closed<a name="line.61"></a>
+<span class="sourceLineNo">062</span> protected boolean closed = false;<a
name="line.62"></a>
+<span class="sourceLineNo">063</span><a name="line.63"></a>
+<span class="sourceLineNo">064</span> protected SegmentScanner(Segment
segment, long readPoint) {<a name="line.64"></a>
+<span class="sourceLineNo">065</span> this(segment, readPoint,
DEFAULT_SCANNER_ORDER);<a name="line.65"></a>
+<span class="sourceLineNo">066</span> }<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> * @param scannerOrder see {@link
KeyValueScanner#getScannerOrder()}.<a name="line.69"></a>
+<span class="sourceLineNo">070</span> * Scanners are ordered from 0 (oldest)
to newest in increasing order.<a name="line.70"></a>
+<span class="sourceLineNo">071</span> */<a name="line.71"></a>
+<span class="sourceLineNo">072</span> protected SegmentScanner(Segment
segment, long readPoint, long scannerOrder) {<a name="line.72"></a>
+<span class="sourceLineNo">073</span> this.segment = segment;<a
name="line.73"></a>
+<span class="sourceLineNo">074</span> this.readPoint = readPoint;<a
name="line.74"></a>
+<span class="sourceLineNo">075</span> //increase the reference count so the
underlying structure will not be de-allocated<a name="line.75"></a>
+<span class="sourceLineNo">076</span> this.segment.incScannerCount();<a
name="line.76"></a>
+<span class="sourceLineNo">077</span> iter = segment.iterator();<a
name="line.77"></a>
+<span class="sourceLineNo">078</span> // the initialization of the current
is required for working with heap of SegmentScanners<a name="line.78"></a>
+<span class="sourceLineNo">079</span> updateCurrent();<a name="line.79"></a>
+<span class="sourceLineNo">080</span> this.scannerOrder = scannerOrder;<a
name="line.80"></a>
+<span class="sourceLineNo">081</span> if (current == null) {<a
name="line.81"></a>
+<span class="sourceLineNo">082</span> // nothing to fetch from this
scanner<a name="line.82"></a>
+<span class="sourceLineNo">083</span> close();<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> /**<a name="line.87"></a>
+<span class="sourceLineNo">088</span> * Look at the next Cell in this
scanner, but do not iterate the scanner<a name="line.88"></a>
+<span class="sourceLineNo">089</span> * @return the currently observed
Cell<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 Cell peek() { // sanity
check, the current should be always valid<a name="line.92"></a>
+<span class="sourceLineNo">093</span> if (closed) {<a name="line.93"></a>
+<span class="sourceLineNo">094</span> return null;<a name="line.94"></a>
+<span class="sourceLineNo">095</span> }<a name="line.95"></a>
+<span class="sourceLineNo">096</span> if (current!=null &&
current.getSequenceId() > readPoint) {<a name="line.96"></a>
+<span class="sourceLineNo">097</span> throw new RuntimeException("current
is invalid: read point is "+readPoint+", " +<a name="line.97"></a>
+<span class="sourceLineNo">098</span> "while current sequence id is "
+current.getSequenceId());<a name="line.98"></a>
+<span class="sourceLineNo">099</span> }<a name="line.99"></a>
+<span class="sourceLineNo">100</span> return current;<a name="line.100"></a>
+<span class="sourceLineNo">101</span> }<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> * Return the next Cell in this
scanner, iterating the scanner<a name="line.104"></a>
+<span class="sourceLineNo">105</span> * @return the next Cell or null if end
of scanner<a name="line.105"></a>
+<span class="sourceLineNo">106</span> */<a name="line.106"></a>
+<span class="sourceLineNo">107</span> @Override<a name="line.107"></a>
+<span class="sourceLineNo">108</span> public Cell next() throws IOException
{<a name="line.108"></a>
+<span class="sourceLineNo">109</span> if (closed) {<a name="line.109"></a>
+<span class="sourceLineNo">110</span> return null;<a name="line.110"></a>
+<span class="sourceLineNo">111</span> }<a name="line.111"></a>
+<span class="sourceLineNo">112</span> Cell oldCurrent = current;<a
name="line.112"></a>
+<span class="sourceLineNo">113</span> updateCurrent(); //
update the currently observed Cell<a name="line.113"></a>
+<span class="sourceLineNo">114</span> return oldCurrent;<a
name="line.114"></a>
+<span class="sourceLineNo">115</span> }<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> * Seek the scanner at or after the
specified Cell.<a name="line.118"></a>
+<span class="sourceLineNo">119</span> * @param cell seek value<a
name="line.119"></a>
+<span class="sourceLineNo">120</span> * @return true if scanner has values
left, false if end of scanner<a name="line.120"></a>
+<span class="sourceLineNo">121</span> */<a name="line.121"></a>
+<span class="sourceLineNo">122</span> @Override<a name="line.122"></a>
+<span class="sourceLineNo">123</span> public boolean seek(Cell cell) throws
IOException {<a name="line.123"></a>
+<span class="sourceLineNo">124</span> if (closed) {<a name="line.124"></a>
+<span class="sourceLineNo">125</span> return false;<a name="line.125"></a>
+<span class="sourceLineNo">126</span> }<a name="line.126"></a>
+<span class="sourceLineNo">127</span> if(cell == null) {<a
name="line.127"></a>
+<span class="sourceLineNo">128</span> close();<a name="line.128"></a>
+<span class="sourceLineNo">129</span> return false;<a name="line.129"></a>
+<span class="sourceLineNo">130</span> }<a name="line.130"></a>
+<span class="sourceLineNo">131</span> // restart the iterator from new
key<a name="line.131"></a>
+<span class="sourceLineNo">132</span> iter = getIterator(cell);<a
name="line.132"></a>
+<span class="sourceLineNo">133</span> // last is going to be reinitialized
in the next getNext() call<a name="line.133"></a>
+<span class="sourceLineNo">134</span> last = null;<a name="line.134"></a>
+<span class="sourceLineNo">135</span> updateCurrent();<a
name="line.135"></a>
+<span class="sourceLineNo">136</span> return (current != null);<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> protected Iterator<Cell>
getIterator(Cell cell) {<a name="line.139"></a>
+<span class="sourceLineNo">140</span> return
segment.tailSet(cell).iterator();<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> /**<a name="line.143"></a>
+<span class="sourceLineNo">144</span> * Reseek the scanner at or after the
specified KeyValue.<a name="line.144"></a>
+<span class="sourceLineNo">145</span> * This method is guaranteed to seek at
or after the required key only if the<a name="line.145"></a>
+<span class="sourceLineNo">146</span> * key comes after the current position
of the scanner. Should not be used<a name="line.146"></a>
+<span class="sourceLineNo">147</span> * to seek to a key which may come
before the current position.<a name="line.147"></a>
+<span class="sourceLineNo">148</span> *<a name="line.148"></a>
+<span class="sourceLineNo">149</span> * @param cell seek value (should be
non-null)<a name="line.149"></a>
+<span class="sourceLineNo">150</span> * @return true if scanner has values
left, false if end of scanner<a name="line.150"></a>
+<span class="sourceLineNo">151</span> */<a name="line.151"></a>
+<span class="sourceLineNo">152</span> @Override<a name="line.152"></a>
+<span class="sourceLineNo">153</span> public boolean reseek(Cell cell) throws
IOException {<a name="line.153"></a>
+<span class="sourceLineNo">154</span> if (closed) {<a name="line.154"></a>
+<span class="sourceLineNo">155</span> return false;<a name="line.155"></a>
+<span class="sourceLineNo">156</span> }<a name="line.156"></a>
+<span class="sourceLineNo">157</span> /*<a name="line.157"></a>
+<span class="sourceLineNo">158</span> See HBASE-4195 & HBASE-3855 &
HBASE-6591 for the background on this implementation.<a name="line.158"></a>
+<span class="sourceLineNo">159</span> This code is executed concurrently
with flush and puts, without locks.<a name="line.159"></a>
+<span class="sourceLineNo">160</span> The ideal implementation for
performance would use the sub skip list implicitly<a name="line.160"></a>
+<span class="sourceLineNo">161</span> pointed by the iterator.
Unfortunately the Java API does not offer a method to<a name="line.161"></a>
+<span class="sourceLineNo">162</span> get it. So we remember the last keys
we iterated to and restore<a name="line.162"></a>
+<span class="sourceLineNo">163</span> the reseeked set to at least that
point.<a name="line.163"></a>
+<span class="sourceLineNo">164</span> */<a name="line.164"></a>
+<span class="sourceLineNo">165</span> iter = getIterator(getHighest(cell,
last));<a name="line.165"></a>
+<span class="sourceLineNo">166</span> updateCurrent();<a
name="line.166"></a>
+<span class="sourceLineNo">167</span> return (current != null);<a
name="line.167"></a>
+<span class="sourceLineNo">168</span> }<a name="line.168"></a>
+<span class="sourceLineNo">169</span><a name="line.169"></a>
+<span class="sourceLineNo">170</span> /**<a name="line.170"></a>
+<span class="sourceLineNo">171</span> * Seek the scanner at or before the
row of specified Cell, it firstly<a name="line.171"></a>
+<span class="sourceLineNo">172</span> * tries to seek the scanner at or
after the specified Cell, return if<a name="line.172"></a>
+<span class="sourceLineNo">173</span> * peek KeyValue of scanner has the
same row with specified Cell,<a name="line.173"></a>
+<span class="sourceLineNo">174</span> * otherwise seek the scanner at the
first Cell of the row which is the<a name="line.174"></a>
+<span class="sourceLineNo">175</span> * previous row of specified KeyValue<a
name="line.175"></a>
+<span class="sourceLineNo">176</span> *<a name="line.176"></a>
+<span class="sourceLineNo">177</span> * @param key seek Cell<a
name="line.177"></a>
+<span class="sourceLineNo">178</span> * @return true if the scanner is at
the valid KeyValue, false if such Cell does not exist<a name="line.178"></a>
+<span class="sourceLineNo">179</span> */<a name="line.179"></a>
+<span class="sourceLineNo">180</span> @Override<a name="line.180"></a>
+<span class="sourceLineNo">181</span> public boolean backwardSeek(Cell key)
throws IOException {<a name="line.181"></a>
+<span class="sourceLineNo">182</span> if (closed) {<a name="line.182"></a>
+<span class="sourceLineNo">183</span> return false;<a name="line.183"></a>
+<span class="sourceLineNo">184</span> }<a name="line.184"></a>
+<span class="sourceLineNo">185</span> seek(key); // seek forward then go
backward<a name="line.185"></a>
+<span class="sourceLineNo">186</span> if (peek() == null ||
segment.compareRows(peek(), key) > 0) {<a name="line.186"></a>
+<span class="sourceLineNo">187</span> return seekToPreviousRow(key);<a
name="line.187"></a>
+<span class="sourceLineNo">188</span> }<a name="line.188"></a>
+<span class="sourceLineNo">189</span> return true;<a name="line.189"></a>
+<span class="sourceLineNo">190</span> }<a name="line.190"></a>
+<span class="sourceLineNo">191</span><a name="line.191"></a>
+<span class="sourceLineNo">192</span> /**<a name="line.192"></a>
+<span class="sourceLineNo">193</span> * Seek the scanner at the first Cell
of the row which is the previous row<a name="line.193"></a>
+<span class="sourceLineNo">194</span> * of specified key<a
name="line.194"></a>
+<span class="sourceLineNo">195</span> *<a name="line.195"></a>
+<span class="sourceLineNo">196</span> * @param cell seek value<a
name="line.196"></a>
+<span class="sourceLineNo">197</span> * @return true if the scanner at the
first valid Cell of previous row,<a name="line.197"></a>
+<span class="sourceLineNo">198</span> * false if not existing such
Cell<a name="line.198"></a>
+<span class="sourceLineNo">199</span> */<a name="line.199"></a>
+<span class="sourceLineNo">200</span> @Override<a name="line.200"></a>
+<span class="sourceLineNo">201</span> public boolean seekToPreviousRow(Cell
cell) throws IOException {<a name="line.201"></a>
+<span class="sourceLineNo">202</span> if (closed) {<a name="line.202"></a>
+<span class="sourceLineNo">203</span> return false;<a name="line.203"></a>
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