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From mi...@apache.org
Subject [10/52] [partial] hbase-site git commit: Published site at 950d547dae684155020edb879a343bee1bf18e97.
Date Mon, 29 Aug 2016 15:33:00 GMT
http://git-wip-us.apache.org/repos/asf/hbase-site/blob/45a663dd/devapidocs/src-html/org/apache/hadoop/hbase/master/snapshot/SnapshotFileCache.SnapshotDirectoryInfo.html
----------------------------------------------------------------------
diff --git a/devapidocs/src-html/org/apache/hadoop/hbase/master/snapshot/SnapshotFileCache.SnapshotDirectoryInfo.html b/devapidocs/src-html/org/apache/hadoop/hbase/master/snapshot/SnapshotFileCache.SnapshotDirectoryInfo.html
index ac4f63e..9ec3893 100644
--- a/devapidocs/src-html/org/apache/hadoop/hbase/master/snapshot/SnapshotFileCache.SnapshotDirectoryInfo.html
+++ b/devapidocs/src-html/org/apache/hadoop/hbase/master/snapshot/SnapshotFileCache.SnapshotDirectoryInfo.html
@@ -35,358 +35,366 @@
 <span class="sourceLineNo">027</span>import java.util.Set;<a name="line.27"></a>
 <span class="sourceLineNo">028</span>import java.util.Timer;<a name="line.28"></a>
 <span class="sourceLineNo">029</span>import java.util.TimerTask;<a name="line.29"></a>
-<span class="sourceLineNo">030</span><a name="line.30"></a>
-<span class="sourceLineNo">031</span>import com.google.common.annotations.VisibleForTesting;<a name="line.31"></a>
-<span class="sourceLineNo">032</span>import com.google.common.collect.Lists;<a name="line.32"></a>
-<span class="sourceLineNo">033</span>import org.apache.commons.logging.Log;<a name="line.33"></a>
-<span class="sourceLineNo">034</span>import org.apache.commons.logging.LogFactory;<a name="line.34"></a>
-<span class="sourceLineNo">035</span>import org.apache.hadoop.hbase.classification.InterfaceAudience;<a name="line.35"></a>
-<span class="sourceLineNo">036</span>import org.apache.hadoop.hbase.classification.InterfaceStability;<a name="line.36"></a>
-<span class="sourceLineNo">037</span>import org.apache.hadoop.conf.Configuration;<a name="line.37"></a>
-<span class="sourceLineNo">038</span>import org.apache.hadoop.fs.FileStatus;<a name="line.38"></a>
-<span class="sourceLineNo">039</span>import org.apache.hadoop.fs.FileSystem;<a name="line.39"></a>
-<span class="sourceLineNo">040</span>import org.apache.hadoop.fs.Path;<a name="line.40"></a>
-<span class="sourceLineNo">041</span>import org.apache.hadoop.hbase.Stoppable;<a name="line.41"></a>
-<span class="sourceLineNo">042</span>import org.apache.hadoop.hbase.snapshot.CorruptedSnapshotException;<a name="line.42"></a>
-<span class="sourceLineNo">043</span>import org.apache.hadoop.hbase.snapshot.SnapshotDescriptionUtils;<a name="line.43"></a>
-<span class="sourceLineNo">044</span>import org.apache.hadoop.hbase.util.FSUtils;<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> * Intelligently keep track of all the files for all the snapshots.<a name="line.47"></a>
-<span class="sourceLineNo">048</span> * &lt;p&gt;<a name="line.48"></a>
-<span class="sourceLineNo">049</span> * A cache of files is kept to avoid querying the {@link FileSystem} frequently. If there is a cache<a name="line.49"></a>
-<span class="sourceLineNo">050</span> * miss the directory modification time is used to ensure that we don't rescan directories that we<a name="line.50"></a>
-<span class="sourceLineNo">051</span> * already have in cache. We only check the modification times of the snapshot directories<a name="line.51"></a>
-<span class="sourceLineNo">052</span> * (/hbase/.snapshot/[snapshot_name]) to determine if the files need to be loaded into the cache.<a name="line.52"></a>
-<span class="sourceLineNo">053</span> * &lt;p&gt;<a name="line.53"></a>
-<span class="sourceLineNo">054</span> * New snapshots will be added to the cache and deleted snapshots will be removed when we refresh<a name="line.54"></a>
-<span class="sourceLineNo">055</span> * the cache. If the files underneath a snapshot directory are changed, but not the snapshot itself,<a name="line.55"></a>
-<span class="sourceLineNo">056</span> * we will ignore updates to that snapshot's files.<a name="line.56"></a>
-<span class="sourceLineNo">057</span> * &lt;p&gt;<a name="line.57"></a>
-<span class="sourceLineNo">058</span> * This is sufficient because each snapshot has its own directory and is added via an atomic rename<a name="line.58"></a>
-<span class="sourceLineNo">059</span> * &lt;i&gt;once&lt;/i&gt;, when the snapshot is created. We don't need to worry about the data in the snapshot<a name="line.59"></a>
-<span class="sourceLineNo">060</span> * being run.<a name="line.60"></a>
-<span class="sourceLineNo">061</span> * &lt;p&gt;<a name="line.61"></a>
-<span class="sourceLineNo">062</span> * Further, the cache is periodically refreshed ensure that files in snapshots that were deleted are<a name="line.62"></a>
-<span class="sourceLineNo">063</span> * also removed from the cache.<a name="line.63"></a>
-<span class="sourceLineNo">064</span> * &lt;p&gt;<a name="line.64"></a>
-<span class="sourceLineNo">065</span> * A {@link SnapshotFileCache.SnapshotFileInspector} must be passed when creating &lt;tt&gt;this&lt;/tt&gt; to<a name="line.65"></a>
-<span class="sourceLineNo">066</span> * allow extraction of files under /hbase/.snapshot/[snapshot name] directory, for each snapshot.<a name="line.66"></a>
-<span class="sourceLineNo">067</span> * This allows you to only cache files under, for instance, all the logs in the .logs directory or<a name="line.67"></a>
-<span class="sourceLineNo">068</span> * all the files under all the regions.<a name="line.68"></a>
-<span class="sourceLineNo">069</span> * &lt;p&gt;<a name="line.69"></a>
-<span class="sourceLineNo">070</span> * &lt;tt&gt;this&lt;/tt&gt; also considers all running snapshots (those under /hbase/.snapshot/.tmp) as valid<a name="line.70"></a>
-<span class="sourceLineNo">071</span> * snapshots and will attempt to cache files from those snapshots as well.<a name="line.71"></a>
-<span class="sourceLineNo">072</span> * &lt;p&gt;<a name="line.72"></a>
-<span class="sourceLineNo">073</span> * Queries about a given file are thread-safe with respect to multiple queries and cache refreshes.<a name="line.73"></a>
-<span class="sourceLineNo">074</span> */<a name="line.74"></a>
-<span class="sourceLineNo">075</span>@InterfaceAudience.Private<a name="line.75"></a>
-<span class="sourceLineNo">076</span>@InterfaceStability.Evolving<a name="line.76"></a>
-<span class="sourceLineNo">077</span>public class SnapshotFileCache implements Stoppable {<a name="line.77"></a>
-<span class="sourceLineNo">078</span>  interface SnapshotFileInspector {<a name="line.78"></a>
-<span class="sourceLineNo">079</span>    /**<a name="line.79"></a>
-<span class="sourceLineNo">080</span>     * Returns a collection of file names needed by the snapshot.<a name="line.80"></a>
-<span class="sourceLineNo">081</span>     * @param snapshotDir {@link Path} to the snapshot directory to scan.<a name="line.81"></a>
-<span class="sourceLineNo">082</span>     * @return the collection of file names needed by the snapshot.<a name="line.82"></a>
-<span class="sourceLineNo">083</span>     */<a name="line.83"></a>
-<span class="sourceLineNo">084</span>    Collection&lt;String&gt; filesUnderSnapshot(final Path snapshotDir) throws IOException;<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>  private static final Log LOG = LogFactory.getLog(SnapshotFileCache.class);<a name="line.87"></a>
-<span class="sourceLineNo">088</span>  private volatile boolean stop = false;<a name="line.88"></a>
-<span class="sourceLineNo">089</span>  private final FileSystem fs;<a name="line.89"></a>
-<span class="sourceLineNo">090</span>  private final SnapshotFileInspector fileInspector;<a name="line.90"></a>
-<span class="sourceLineNo">091</span>  private final Path snapshotDir;<a name="line.91"></a>
-<span class="sourceLineNo">092</span>  private final Set&lt;String&gt; cache = new HashSet&lt;String&gt;();<a name="line.92"></a>
-<span class="sourceLineNo">093</span>  /**<a name="line.93"></a>
-<span class="sourceLineNo">094</span>   * This is a helper map of information about the snapshot directories so we don't need to rescan<a name="line.94"></a>
-<span class="sourceLineNo">095</span>   * them if they haven't changed since the last time we looked.<a name="line.95"></a>
-<span class="sourceLineNo">096</span>   */<a name="line.96"></a>
-<span class="sourceLineNo">097</span>  private final Map&lt;String, SnapshotDirectoryInfo&gt; snapshots =<a name="line.97"></a>
-<span class="sourceLineNo">098</span>      new HashMap&lt;String, SnapshotDirectoryInfo&gt;();<a name="line.98"></a>
-<span class="sourceLineNo">099</span>  private final Timer refreshTimer;<a name="line.99"></a>
-<span class="sourceLineNo">100</span><a name="line.100"></a>
-<span class="sourceLineNo">101</span>  private long lastModifiedTime = Long.MIN_VALUE;<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>   * Create a snapshot file cache for all snapshots under the specified [root]/.snapshot on the<a name="line.104"></a>
-<span class="sourceLineNo">105</span>   * filesystem.<a name="line.105"></a>
-<span class="sourceLineNo">106</span>   * &lt;p&gt;<a name="line.106"></a>
-<span class="sourceLineNo">107</span>   * Immediately loads the file cache.<a name="line.107"></a>
-<span class="sourceLineNo">108</span>   * @param conf to extract the configured {@link FileSystem} where the snapshots are stored and<a name="line.108"></a>
-<span class="sourceLineNo">109</span>   *          hbase root directory<a name="line.109"></a>
-<span class="sourceLineNo">110</span>   * @param cacheRefreshPeriod frequency (ms) with which the cache should be refreshed<a name="line.110"></a>
-<span class="sourceLineNo">111</span>   * @param refreshThreadName name of the cache refresh thread<a name="line.111"></a>
-<span class="sourceLineNo">112</span>   * @param inspectSnapshotFiles Filter to apply to each snapshot to extract the files.<a name="line.112"></a>
-<span class="sourceLineNo">113</span>   * @throws IOException if the {@link FileSystem} or root directory cannot be loaded<a name="line.113"></a>
-<span class="sourceLineNo">114</span>   */<a name="line.114"></a>
-<span class="sourceLineNo">115</span>  public SnapshotFileCache(Configuration conf, long cacheRefreshPeriod, String refreshThreadName,<a name="line.115"></a>
-<span class="sourceLineNo">116</span>      SnapshotFileInspector inspectSnapshotFiles) throws IOException {<a name="line.116"></a>
-<span class="sourceLineNo">117</span>    this(FSUtils.getCurrentFileSystem(conf), FSUtils.getRootDir(conf), 0, cacheRefreshPeriod,<a name="line.117"></a>
-<span class="sourceLineNo">118</span>        refreshThreadName, inspectSnapshotFiles);<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>   * Create a snapshot file cache for all snapshots under the specified [root]/.snapshot on the<a name="line.122"></a>
-<span class="sourceLineNo">123</span>   * filesystem<a name="line.123"></a>
-<span class="sourceLineNo">124</span>   * @param fs {@link FileSystem} where the snapshots are stored<a name="line.124"></a>
-<span class="sourceLineNo">125</span>   * @param rootDir hbase root directory<a name="line.125"></a>
-<span class="sourceLineNo">126</span>   * @param cacheRefreshPeriod period (ms) with which the cache should be refreshed<a name="line.126"></a>
-<span class="sourceLineNo">127</span>   * @param cacheRefreshDelay amount of time to wait for the cache to be refreshed<a name="line.127"></a>
-<span class="sourceLineNo">128</span>   * @param refreshThreadName name of the cache refresh thread<a name="line.128"></a>
-<span class="sourceLineNo">129</span>   * @param inspectSnapshotFiles Filter to apply to each snapshot to extract the files.<a name="line.129"></a>
-<span class="sourceLineNo">130</span>   */<a name="line.130"></a>
-<span class="sourceLineNo">131</span>  public SnapshotFileCache(FileSystem fs, Path rootDir, long cacheRefreshPeriod,<a name="line.131"></a>
-<span class="sourceLineNo">132</span>      long cacheRefreshDelay, String refreshThreadName, SnapshotFileInspector inspectSnapshotFiles) {<a name="line.132"></a>
-<span class="sourceLineNo">133</span>    this.fs = fs;<a name="line.133"></a>
-<span class="sourceLineNo">134</span>    this.fileInspector = inspectSnapshotFiles;<a name="line.134"></a>
-<span class="sourceLineNo">135</span>    this.snapshotDir = SnapshotDescriptionUtils.getSnapshotsDir(rootDir);<a name="line.135"></a>
-<span class="sourceLineNo">136</span>    // periodically refresh the file cache to make sure we aren't superfluously saving files.<a name="line.136"></a>
-<span class="sourceLineNo">137</span>    this.refreshTimer = new Timer(refreshThreadName, true);<a name="line.137"></a>
-<span class="sourceLineNo">138</span>    this.refreshTimer.scheduleAtFixedRate(new RefreshCacheTask(), cacheRefreshDelay,<a name="line.138"></a>
-<span class="sourceLineNo">139</span>      cacheRefreshPeriod);<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>   * Trigger a cache refresh, even if its before the next cache refresh. Does not affect pending<a name="line.143"></a>
-<span class="sourceLineNo">144</span>   * cache refreshes.<a name="line.144"></a>
-<span class="sourceLineNo">145</span>   * &lt;p&gt;<a name="line.145"></a>
-<span class="sourceLineNo">146</span>   * Blocks until the cache is refreshed.<a name="line.146"></a>
-<span class="sourceLineNo">147</span>   * &lt;p&gt;<a name="line.147"></a>
-<span class="sourceLineNo">148</span>   * Exposed for TESTING.<a name="line.148"></a>
-<span class="sourceLineNo">149</span>   */<a name="line.149"></a>
-<span class="sourceLineNo">150</span>  public void triggerCacheRefreshForTesting() {<a name="line.150"></a>
-<span class="sourceLineNo">151</span>    try {<a name="line.151"></a>
-<span class="sourceLineNo">152</span>      SnapshotFileCache.this.refreshCache();<a name="line.152"></a>
-<span class="sourceLineNo">153</span>    } catch (IOException e) {<a name="line.153"></a>
-<span class="sourceLineNo">154</span>      LOG.warn("Failed to refresh snapshot hfile cache!", e);<a name="line.154"></a>
-<span class="sourceLineNo">155</span>    }<a name="line.155"></a>
-<span class="sourceLineNo">156</span>    LOG.debug("Current cache:" + cache);<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>  /**<a name="line.159"></a>
-<span class="sourceLineNo">160</span>   * Check to see if any of the passed file names is contained in any of the snapshots.<a name="line.160"></a>
-<span class="sourceLineNo">161</span>   * First checks an in-memory cache of the files to keep. If its not in the cache, then the cache<a name="line.161"></a>
-<span class="sourceLineNo">162</span>   * is refreshed and the cache checked again for that file.<a name="line.162"></a>
-<span class="sourceLineNo">163</span>   * This ensures that we never return files that exist.<a name="line.163"></a>
-<span class="sourceLineNo">164</span>   * &lt;p&gt;<a name="line.164"></a>
-<span class="sourceLineNo">165</span>   * Note this may lead to periodic false positives for the file being referenced. Periodically, the<a name="line.165"></a>
-<span class="sourceLineNo">166</span>   * cache is refreshed even if there are no requests to ensure that the false negatives get removed<a name="line.166"></a>
-<span class="sourceLineNo">167</span>   * eventually. For instance, suppose you have a file in the snapshot and it gets loaded into the<a name="line.167"></a>
-<span class="sourceLineNo">168</span>   * cache. Then at some point later that snapshot is deleted. If the cache has not been refreshed<a name="line.168"></a>
-<span class="sourceLineNo">169</span>   * at that point, cache will still think the file system contains that file and return<a name="line.169"></a>
-<span class="sourceLineNo">170</span>   * &lt;tt&gt;true&lt;/tt&gt;, even if it is no longer present (false positive). However, if the file never was<a name="line.170"></a>
-<span class="sourceLineNo">171</span>   * on the filesystem, we will never find it and always return &lt;tt&gt;false&lt;/tt&gt;.<a name="line.171"></a>
-<span class="sourceLineNo">172</span>   * @param files file to check, NOTE: Relies that files are loaded from hdfs before method<a name="line.172"></a>
-<span class="sourceLineNo">173</span>   *              is called (NOT LAZY)<a name="line.173"></a>
-<span class="sourceLineNo">174</span>   * @return &lt;tt&gt;unReferencedFiles&lt;/tt&gt; the collection of files that do not have snapshot references<a name="line.174"></a>
-<span class="sourceLineNo">175</span>   * @throws IOException if there is an unexpected error reaching the filesystem.<a name="line.175"></a>
-<span class="sourceLineNo">176</span>   */<a name="line.176"></a>
-<span class="sourceLineNo">177</span>  // XXX this is inefficient to synchronize on the method, when what we really need to guard against<a name="line.177"></a>
-<span class="sourceLineNo">178</span>  // is an illegal access to the cache. Really we could do a mutex-guarded pointer swap on the<a name="line.178"></a>
-<span class="sourceLineNo">179</span>  // cache, but that seems overkill at the moment and isn't necessarily a bottleneck.<a name="line.179"></a>
-<span class="sourceLineNo">180</span>  public synchronized Iterable&lt;FileStatus&gt; getUnreferencedFiles(Iterable&lt;FileStatus&gt; files)<a name="line.180"></a>
-<span class="sourceLineNo">181</span>      throws IOException {<a name="line.181"></a>
-<span class="sourceLineNo">182</span>    List&lt;FileStatus&gt; unReferencedFiles = Lists.newArrayList();<a name="line.182"></a>
-<span class="sourceLineNo">183</span>    List&lt;String&gt; snapshotsInProgress = null;<a name="line.183"></a>
-<span class="sourceLineNo">184</span>    boolean refreshed = false;<a name="line.184"></a>
-<span class="sourceLineNo">185</span>    for (FileStatus file : files) {<a name="line.185"></a>
-<span class="sourceLineNo">186</span>      String fileName = file.getPath().getName();<a name="line.186"></a>
-<span class="sourceLineNo">187</span>      if (!refreshed &amp;&amp; !cache.contains(fileName)) {<a name="line.187"></a>
-<span class="sourceLineNo">188</span>        refreshCache();<a name="line.188"></a>
-<span class="sourceLineNo">189</span>        refreshed = true;<a name="line.189"></a>
-<span class="sourceLineNo">190</span>      }<a name="line.190"></a>
-<span class="sourceLineNo">191</span>      if (cache.contains(fileName)) {<a name="line.191"></a>
-<span class="sourceLineNo">192</span>        continue;<a name="line.192"></a>
-<span class="sourceLineNo">193</span>      }<a name="line.193"></a>
-<span class="sourceLineNo">194</span>      if (snapshotsInProgress == null) {<a name="line.194"></a>
-<span class="sourceLineNo">195</span>        snapshotsInProgress = getSnapshotsInProgress();<a name="line.195"></a>
-<span class="sourceLineNo">196</span>      }<a name="line.196"></a>
-<span class="sourceLineNo">197</span>      if (snapshotsInProgress.contains(fileName)) {<a name="line.197"></a>
-<span class="sourceLineNo">198</span>        continue;<a name="line.198"></a>
-<span class="sourceLineNo">199</span>      }<a name="line.199"></a>
-<span class="sourceLineNo">200</span>      unReferencedFiles.add(file);<a name="line.200"></a>
-<span class="sourceLineNo">201</span>    }<a name="line.201"></a>
-<span class="sourceLineNo">202</span>    return unReferencedFiles;<a name="line.202"></a>
-<span class="sourceLineNo">203</span>  }<a name="line.203"></a>
-<span class="sourceLineNo">204</span><a name="line.204"></a>
-<span class="sourceLineNo">205</span>  private synchronized void refreshCache() throws IOException {<a name="line.205"></a>
-<span class="sourceLineNo">206</span>    long lastTimestamp = Long.MAX_VALUE;<a name="line.206"></a>
-<span class="sourceLineNo">207</span>    boolean hasChanges = false;<a name="line.207"></a>
-<span class="sourceLineNo">208</span><a name="line.208"></a>
-<span class="sourceLineNo">209</span>    // get the status of the snapshots directory and check if it is has changes<a name="line.209"></a>
-<span class="sourceLineNo">210</span>    try {<a name="line.210"></a>
-<span class="sourceLineNo">211</span>      FileStatus dirStatus = fs.getFileStatus(snapshotDir);<a name="line.211"></a>
-<span class="sourceLineNo">212</span>      lastTimestamp = dirStatus.getModificationTime();<a name="line.212"></a>
-<span class="sourceLineNo">213</span>      hasChanges |= (lastTimestamp &gt;= lastModifiedTime);<a name="line.213"></a>
-<span class="sourceLineNo">214</span>    } catch (FileNotFoundException e) {<a name="line.214"></a>
-<span class="sourceLineNo">215</span>      if (this.cache.size() &gt; 0) {<a name="line.215"></a>
-<span class="sourceLineNo">216</span>        LOG.error("Snapshot directory: " + snapshotDir + " doesn't exist");<a name="line.216"></a>
-<span class="sourceLineNo">217</span>      }<a name="line.217"></a>
-<span class="sourceLineNo">218</span>      return;<a name="line.218"></a>
-<span class="sourceLineNo">219</span>    }<a name="line.219"></a>
-<span class="sourceLineNo">220</span><a name="line.220"></a>
-<span class="sourceLineNo">221</span>    // get the status of the snapshots temporary directory and check if it has changes<a name="line.221"></a>
-<span class="sourceLineNo">222</span>    // The top-level directory timestamp is not updated, so we have to check the inner-level.<a name="line.222"></a>
-<span class="sourceLineNo">223</span>    try {<a name="line.223"></a>
-<span class="sourceLineNo">224</span>      Path snapshotTmpDir = new Path(snapshotDir, SnapshotDescriptionUtils.SNAPSHOT_TMP_DIR_NAME);<a name="line.224"></a>
-<span class="sourceLineNo">225</span>      FileStatus tempDirStatus = fs.getFileStatus(snapshotTmpDir);<a name="line.225"></a>
-<span class="sourceLineNo">226</span>      lastTimestamp = Math.min(lastTimestamp, tempDirStatus.getModificationTime());<a name="line.226"></a>
-<span class="sourceLineNo">227</span>      hasChanges |= (lastTimestamp &gt;= lastModifiedTime);<a name="line.227"></a>
-<span class="sourceLineNo">228</span>      if (!hasChanges) {<a name="line.228"></a>
-<span class="sourceLineNo">229</span>        FileStatus[] tmpSnapshots = FSUtils.listStatus(fs, snapshotDir);<a name="line.229"></a>
-<span class="sourceLineNo">230</span>        if (tmpSnapshots != null) {<a name="line.230"></a>
-<span class="sourceLineNo">231</span>          for (FileStatus dirStatus: tmpSnapshots) {<a name="line.231"></a>
-<span class="sourceLineNo">232</span>            lastTimestamp = Math.min(lastTimestamp, dirStatus.getModificationTime());<a name="line.232"></a>
-<span class="sourceLineNo">233</span>          }<a name="line.233"></a>
-<span class="sourceLineNo">234</span>          hasChanges |= (lastTimestamp &gt;= lastModifiedTime);<a name="line.234"></a>
-<span class="sourceLineNo">235</span>        }<a name="line.235"></a>
-<span class="sourceLineNo">236</span>      }<a name="line.236"></a>
-<span class="sourceLineNo">237</span>    } catch (FileNotFoundException e) {<a name="line.237"></a>
-<span class="sourceLineNo">238</span>      // Nothing todo, if the tmp dir is empty<a name="line.238"></a>
-<span class="sourceLineNo">239</span>    }<a name="line.239"></a>
-<span class="sourceLineNo">240</span><a name="line.240"></a>
-<span class="sourceLineNo">241</span>    // if the snapshot directory wasn't modified since we last check, we are done<a name="line.241"></a>
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-<span class="sourceLineNo">244</span>    }<a name="line.244"></a>
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-<span class="sourceLineNo">246</span>    // directory was modified, so we need to reload our cache<a name="line.246"></a>
-<span class="sourceLineNo">247</span>    // there could be a slight race here where we miss the cache, check the directory modification<a name="line.247"></a>
-<span class="sourceLineNo">248</span>    // time, then someone updates the directory, causing us to not scan the directory again.<a name="line.248"></a>
-<span class="sourceLineNo">249</span>    // However, snapshot directories are only created once, so this isn't an issue.<a name="line.249"></a>
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-<span class="sourceLineNo">253</span><a name="line.253"></a>
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-<span class="sourceLineNo">276</span>        // files the latter could occur where I create a snapshot, then delete it, and then make a<a name="line.276"></a>
-<span class="sourceLineNo">277</span>        // new snapshot with the same name. We will need to update the cache the information from<a name="line.277"></a>
-<span class="sourceLineNo">278</span>        // that new snapshot, even though it has the same name as the files referenced have<a name="line.278"></a>
-<span class="sourceLineNo">279</span>        // probably changed.<a name="line.279"></a>
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-<span class="sourceLineNo">281</span>          // get all files for the snapshot and create a new info<a name="line.281"></a>
-<span class="sourceLineNo">282</span>          Collection&lt;String&gt; storedFiles = fileInspector.filesUnderSnapshot(snapshot.getPath());<a name="line.282"></a>
-<span class="sourceLineNo">283</span>          files = new SnapshotDirectoryInfo(snapshot.getModificationTime(), storedFiles);<a name="line.283"></a>
-<span class="sourceLineNo">284</span>        }<a name="line.284"></a>
-<span class="sourceLineNo">285</span>        // 3.2 add all the files to cache<a name="line.285"></a>
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-<span class="sourceLineNo">291</span>    // 4. set the snapshots we are tracking<a name="line.291"></a>
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-<span class="sourceLineNo">295</span>  <a name="line.295"></a>
-<span class="sourceLineNo">296</span>  @VisibleForTesting List&lt;String&gt; getSnapshotsInProgress() throws IOException {<a name="line.296"></a>
-<span class="sourceLineNo">297</span>    List&lt;String&gt; snapshotInProgress = Lists.newArrayList();<a name="line.297"></a>
-<span class="sourceLineNo">298</span>    // only add those files to the cache, but not to the known snapshots<a name="line.298"></a>
-<span class="sourceLineNo">299</span>    Path snapshotTmpDir = new Path(snapshotDir, SnapshotDescriptionUtils.SNAPSHOT_TMP_DIR_NAME);<a name="line.299"></a>
-<span class="sourceLineNo">300</span>    // only add those files to the cache, but not to the known snapshots<a name="line.300"></a>
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-<span class="sourceLineNo">302</span>    if (running != null) {<a name="line.302"></a>
-<span class="sourceLineNo">303</span>      for (FileStatus run : running) {<a name="line.303"></a>
-<span class="sourceLineNo">304</span>        try {<a name="line.304"></a>
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-<span class="sourceLineNo">306</span>        } catch (CorruptedSnapshotException e) {<a name="line.306"></a>
-<span class="sourceLineNo">307</span>          // See HBASE-16464<a name="line.307"></a>
-<span class="sourceLineNo">308</span>          if (e.getCause() instanceof FileNotFoundException) {<a name="line.308"></a>
-<span class="sourceLineNo">309</span>            // If the snapshot is not in progress, we will delete it<a name="line.309"></a>
-<span class="sourceLineNo">310</span>            if (!fs.exists(new Path(run.getPath(),<a name="line.310"></a>
-<span class="sourceLineNo">311</span>              SnapshotDescriptionUtils.SNAPSHOT_IN_PROGRESS))) {<a name="line.311"></a>
-<span class="sourceLineNo">312</span>              fs.delete(run.getPath(), true);<a name="line.312"></a>
-<span class="sourceLineNo">313</span>              LOG.warn("delete the " + run.getPath() + " due to exception:", e.getCause());<a name="line.313"></a>
-<span class="sourceLineNo">314</span>            }<a name="line.314"></a>
-<span class="sourceLineNo">315</span>          } else {<a name="line.315"></a>
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-<span class="sourceLineNo">317</span>          }<a name="line.317"></a>
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-<span class="sourceLineNo">324</span>  /**<a name="line.324"></a>
-<span class="sourceLineNo">325</span>   * Simple helper task that just periodically attempts to refresh the cache<a name="line.325"></a>
-<span class="sourceLineNo">326</span>   */<a name="line.326"></a>
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-<span class="sourceLineNo">329</span>    public void run() {<a name="line.329"></a>
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-<span class="sourceLineNo">332</span>      } catch (IOException e) {<a name="line.332"></a>
-<span class="sourceLineNo">333</span>        LOG.warn("Failed to refresh snapshot hfile cache!", e);<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>
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-<span class="sourceLineNo">337</span><a name="line.337"></a>
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-<span class="sourceLineNo">340</span>    if (!this.stop) {<a name="line.340"></a>
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-<span class="sourceLineNo">342</span>      this.refreshTimer.cancel();<a name="line.342"></a>
+<span class="sourceLineNo">030</span>import java.util.concurrent.locks.ReentrantLock;<a name="line.30"></a>
+<span class="sourceLineNo">031</span><a name="line.31"></a>
+<span class="sourceLineNo">032</span>import com.google.common.annotations.VisibleForTesting;<a name="line.32"></a>
+<span class="sourceLineNo">033</span>import com.google.common.collect.Lists;<a name="line.33"></a>
+<span class="sourceLineNo">034</span>import org.apache.commons.logging.Log;<a name="line.34"></a>
+<span class="sourceLineNo">035</span>import org.apache.commons.logging.LogFactory;<a name="line.35"></a>
+<span class="sourceLineNo">036</span>import org.apache.hadoop.hbase.classification.InterfaceAudience;<a name="line.36"></a>
+<span class="sourceLineNo">037</span>import org.apache.hadoop.hbase.classification.InterfaceStability;<a name="line.37"></a>
+<span class="sourceLineNo">038</span>import org.apache.hadoop.conf.Configuration;<a name="line.38"></a>
+<span class="sourceLineNo">039</span>import org.apache.hadoop.fs.FileStatus;<a name="line.39"></a>
+<span class="sourceLineNo">040</span>import org.apache.hadoop.fs.FileSystem;<a name="line.40"></a>
+<span class="sourceLineNo">041</span>import org.apache.hadoop.fs.Path;<a name="line.41"></a>
+<span class="sourceLineNo">042</span>import org.apache.hadoop.hbase.Stoppable;<a name="line.42"></a>
+<span class="sourceLineNo">043</span>import org.apache.hadoop.hbase.snapshot.CorruptedSnapshotException;<a name="line.43"></a>
+<span class="sourceLineNo">044</span>import org.apache.hadoop.hbase.snapshot.SnapshotDescriptionUtils;<a name="line.44"></a>
+<span class="sourceLineNo">045</span>import org.apache.hadoop.hbase.util.FSUtils;<a name="line.45"></a>
+<span class="sourceLineNo">046</span><a name="line.46"></a>
+<span class="sourceLineNo">047</span>/**<a name="line.47"></a>
+<span class="sourceLineNo">048</span> * Intelligently keep track of all the files for all the snapshots.<a name="line.48"></a>
+<span class="sourceLineNo">049</span> * &lt;p&gt;<a name="line.49"></a>
+<span class="sourceLineNo">050</span> * A cache of files is kept to avoid querying the {@link FileSystem} frequently. If there is a cache<a name="line.50"></a>
+<span class="sourceLineNo">051</span> * miss the directory modification time is used to ensure that we don't rescan directories that we<a name="line.51"></a>
+<span class="sourceLineNo">052</span> * already have in cache. We only check the modification times of the snapshot directories<a name="line.52"></a>
+<span class="sourceLineNo">053</span> * (/hbase/.snapshot/[snapshot_name]) to determine if the files need to be loaded into the cache.<a name="line.53"></a>
+<span class="sourceLineNo">054</span> * &lt;p&gt;<a name="line.54"></a>
+<span class="sourceLineNo">055</span> * New snapshots will be added to the cache and deleted snapshots will be removed when we refresh<a name="line.55"></a>
+<span class="sourceLineNo">056</span> * the cache. If the files underneath a snapshot directory are changed, but not the snapshot itself,<a name="line.56"></a>
+<span class="sourceLineNo">057</span> * we will ignore updates to that snapshot's files.<a name="line.57"></a>
+<span class="sourceLineNo">058</span> * &lt;p&gt;<a name="line.58"></a>
+<span class="sourceLineNo">059</span> * This is sufficient because each snapshot has its own directory and is added via an atomic rename<a name="line.59"></a>
+<span class="sourceLineNo">060</span> * &lt;i&gt;once&lt;/i&gt;, when the snapshot is created. We don't need to worry about the data in the snapshot<a name="line.60"></a>
+<span class="sourceLineNo">061</span> * being run.<a name="line.61"></a>
+<span class="sourceLineNo">062</span> * &lt;p&gt;<a name="line.62"></a>
+<span class="sourceLineNo">063</span> * Further, the cache is periodically refreshed ensure that files in snapshots that were deleted are<a name="line.63"></a>
+<span class="sourceLineNo">064</span> * also removed from the cache.<a name="line.64"></a>
+<span class="sourceLineNo">065</span> * &lt;p&gt;<a name="line.65"></a>
+<span class="sourceLineNo">066</span> * A {@link SnapshotFileCache.SnapshotFileInspector} must be passed when creating &lt;tt&gt;this&lt;/tt&gt; to<a name="line.66"></a>
+<span class="sourceLineNo">067</span> * allow extraction of files under /hbase/.snapshot/[snapshot name] directory, for each snapshot.<a name="line.67"></a>
+<span class="sourceLineNo">068</span> * This allows you to only cache files under, for instance, all the logs in the .logs directory or<a name="line.68"></a>
+<span class="sourceLineNo">069</span> * all the files under all the regions.<a name="line.69"></a>
+<span class="sourceLineNo">070</span> * &lt;p&gt;<a name="line.70"></a>
+<span class="sourceLineNo">071</span> * &lt;tt&gt;this&lt;/tt&gt; also considers all running snapshots (those under /hbase/.snapshot/.tmp) as valid<a name="line.71"></a>
+<span class="sourceLineNo">072</span> * snapshots and will attempt to cache files from those snapshots as well.<a name="line.72"></a>
+<span class="sourceLineNo">073</span> * &lt;p&gt;<a name="line.73"></a>
+<span class="sourceLineNo">074</span> * Queries about a given file are thread-safe with respect to multiple queries and cache refreshes.<a name="line.74"></a>
+<span class="sourceLineNo">075</span> */<a name="line.75"></a>
+<span class="sourceLineNo">076</span>@InterfaceAudience.Private<a name="line.76"></a>
+<span class="sourceLineNo">077</span>@InterfaceStability.Evolving<a name="line.77"></a>
+<span class="sourceLineNo">078</span>public class SnapshotFileCache implements Stoppable {<a name="line.78"></a>
+<span class="sourceLineNo">079</span>  interface SnapshotFileInspector {<a name="line.79"></a>
+<span class="sourceLineNo">080</span>    /**<a name="line.80"></a>
+<span class="sourceLineNo">081</span>     * Returns a collection of file names needed by the snapshot.<a name="line.81"></a>
+<span class="sourceLineNo">082</span>     * @param snapshotDir {@link Path} to the snapshot directory to scan.<a name="line.82"></a>
+<span class="sourceLineNo">083</span>     * @return the collection of file names needed by the snapshot.<a name="line.83"></a>
+<span class="sourceLineNo">084</span>     */<a name="line.84"></a>
+<span class="sourceLineNo">085</span>    Collection&lt;String&gt; filesUnderSnapshot(final Path snapshotDir) throws IOException;<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>  private static final Log LOG = LogFactory.getLog(SnapshotFileCache.class);<a name="line.88"></a>
+<span class="sourceLineNo">089</span>  private volatile boolean stop = false;<a name="line.89"></a>
+<span class="sourceLineNo">090</span>  private final FileSystem fs;<a name="line.90"></a>
+<span class="sourceLineNo">091</span>  private final SnapshotFileInspector fileInspector;<a name="line.91"></a>
+<span class="sourceLineNo">092</span>  private final Path snapshotDir;<a name="line.92"></a>
+<span class="sourceLineNo">093</span>  private final Set&lt;String&gt; cache = new HashSet&lt;String&gt;();<a name="line.93"></a>
+<span class="sourceLineNo">094</span>  /**<a name="line.94"></a>
+<span class="sourceLineNo">095</span>   * This is a helper map of information about the snapshot directories so we don't need to rescan<a name="line.95"></a>
+<span class="sourceLineNo">096</span>   * them if they haven't changed since the last time we looked.<a name="line.96"></a>
+<span class="sourceLineNo">097</span>   */<a name="line.97"></a>
+<span class="sourceLineNo">098</span>  private final Map&lt;String, SnapshotDirectoryInfo&gt; snapshots =<a name="line.98"></a>
+<span class="sourceLineNo">099</span>      new HashMap&lt;String, SnapshotDirectoryInfo&gt;();<a name="line.99"></a>
+<span class="sourceLineNo">100</span>  private final Timer refreshTimer;<a name="line.100"></a>
+<span class="sourceLineNo">101</span><a name="line.101"></a>
+<span class="sourceLineNo">102</span>  private long lastModifiedTime = Long.MIN_VALUE;<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>   * Create a snapshot file cache for all snapshots under the specified [root]/.snapshot on the<a name="line.105"></a>
+<span class="sourceLineNo">106</span>   * filesystem.<a name="line.106"></a>
+<span class="sourceLineNo">107</span>   * &lt;p&gt;<a name="line.107"></a>
+<span class="sourceLineNo">108</span>   * Immediately loads the file cache.<a name="line.108"></a>
+<span class="sourceLineNo">109</span>   * @param conf to extract the configured {@link FileSystem} where the snapshots are stored and<a name="line.109"></a>
+<span class="sourceLineNo">110</span>   *          hbase root directory<a name="line.110"></a>
+<span class="sourceLineNo">111</span>   * @param cacheRefreshPeriod frequency (ms) with which the cache should be refreshed<a name="line.111"></a>
+<span class="sourceLineNo">112</span>   * @param refreshThreadName name of the cache refresh thread<a name="line.112"></a>
+<span class="sourceLineNo">113</span>   * @param inspectSnapshotFiles Filter to apply to each snapshot to extract the files.<a name="line.113"></a>
+<span class="sourceLineNo">114</span>   * @throws IOException if the {@link FileSystem} or root directory cannot be loaded<a name="line.114"></a>
+<span class="sourceLineNo">115</span>   */<a name="line.115"></a>
+<span class="sourceLineNo">116</span>  public SnapshotFileCache(Configuration conf, long cacheRefreshPeriod, String refreshThreadName,<a name="line.116"></a>
+<span class="sourceLineNo">117</span>      SnapshotFileInspector inspectSnapshotFiles) throws IOException {<a name="line.117"></a>
+<span class="sourceLineNo">118</span>    this(FSUtils.getCurrentFileSystem(conf), FSUtils.getRootDir(conf), 0, cacheRefreshPeriod,<a name="line.118"></a>
+<span class="sourceLineNo">119</span>        refreshThreadName, inspectSnapshotFiles);<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>  /**<a name="line.122"></a>
+<span class="sourceLineNo">123</span>   * Create a snapshot file cache for all snapshots under the specified [root]/.snapshot on the<a name="line.123"></a>
+<span class="sourceLineNo">124</span>   * filesystem<a name="line.124"></a>
+<span class="sourceLineNo">125</span>   * @param fs {@link FileSystem} where the snapshots are stored<a name="line.125"></a>
+<span class="sourceLineNo">126</span>   * @param rootDir hbase root directory<a name="line.126"></a>
+<span class="sourceLineNo">127</span>   * @param cacheRefreshPeriod period (ms) with which the cache should be refreshed<a name="line.127"></a>
+<span class="sourceLineNo">128</span>   * @param cacheRefreshDelay amount of time to wait for the cache to be refreshed<a name="line.128"></a>
+<span class="sourceLineNo">129</span>   * @param refreshThreadName name of the cache refresh thread<a name="line.129"></a>
+<span class="sourceLineNo">130</span>   * @param inspectSnapshotFiles Filter to apply to each snapshot to extract the files.<a name="line.130"></a>
+<span class="sourceLineNo">131</span>   */<a name="line.131"></a>
+<span class="sourceLineNo">132</span>  public SnapshotFileCache(FileSystem fs, Path rootDir, long cacheRefreshPeriod,<a name="line.132"></a>
+<span class="sourceLineNo">133</span>      long cacheRefreshDelay, String refreshThreadName, SnapshotFileInspector inspectSnapshotFiles) {<a name="line.133"></a>
+<span class="sourceLineNo">134</span>    this.fs = fs;<a name="line.134"></a>
+<span class="sourceLineNo">135</span>    this.fileInspector = inspectSnapshotFiles;<a name="line.135"></a>
+<span class="sourceLineNo">136</span>    this.snapshotDir = SnapshotDescriptionUtils.getSnapshotsDir(rootDir);<a name="line.136"></a>
+<span class="sourceLineNo">137</span>    // periodically refresh the file cache to make sure we aren't superfluously saving files.<a name="line.137"></a>
+<span class="sourceLineNo">138</span>    this.refreshTimer = new Timer(refreshThreadName, true);<a name="line.138"></a>
+<span class="sourceLineNo">139</span>    this.refreshTimer.scheduleAtFixedRate(new RefreshCacheTask(), cacheRefreshDelay,<a name="line.139"></a>
+<span class="sourceLineNo">140</span>      cacheRefreshPeriod);<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>   * Trigger a cache refresh, even if its before the next cache refresh. Does not affect pending<a name="line.144"></a>
+<span class="sourceLineNo">145</span>   * cache refreshes.<a name="line.145"></a>
+<span class="sourceLineNo">146</span>   * &lt;p&gt;<a name="line.146"></a>
+<span class="sourceLineNo">147</span>   * Blocks until the cache is refreshed.<a name="line.147"></a>
+<span class="sourceLineNo">148</span>   * &lt;p&gt;<a name="line.148"></a>
+<span class="sourceLineNo">149</span>   * Exposed for TESTING.<a name="line.149"></a>
+<span class="sourceLineNo">150</span>   */<a name="line.150"></a>
+<span class="sourceLineNo">151</span>  public void triggerCacheRefreshForTesting() {<a name="line.151"></a>
+<span class="sourceLineNo">152</span>    try {<a name="line.152"></a>
+<span class="sourceLineNo">153</span>      SnapshotFileCache.this.refreshCache();<a name="line.153"></a>
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