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Posted to commits@hbase.apache.org by gi...@apache.org on 2017/10/17 15:15:56 UTC
[22/37] hbase-site git commit: Published site at .
http://git-wip-us.apache.org/repos/asf/hbase-site/blob/bd10ee7c/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/wal/FSHLog.html
----------------------------------------------------------------------
diff --git a/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/wal/FSHLog.html b/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/wal/FSHLog.html
index 2918186..c9d92f9 100644
--- a/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/wal/FSHLog.html
+++ b/devapidocs/src-html/org/apache/hadoop/hbase/regionserver/wal/FSHLog.html
@@ -51,22 +51,22 @@
<span class="sourceLineNo">043</span>import org.apache.hadoop.hbase.util.FSUtils;<a name="line.43"></a>
<span class="sourceLineNo">044</span>import org.apache.hadoop.hbase.util.HasThread;<a name="line.44"></a>
<span class="sourceLineNo">045</span>import org.apache.hadoop.hbase.util.Threads;<a name="line.45"></a>
-<span class="sourceLineNo">046</span>import org.apache.hadoop.hbase.wal.FSHLogProvider;<a name="line.46"></a>
-<span class="sourceLineNo">047</span>import org.apache.hadoop.hbase.wal.WALEdit;<a name="line.47"></a>
-<span class="sourceLineNo">048</span>import org.apache.hadoop.hbase.wal.WALFactory;<a name="line.48"></a>
-<span class="sourceLineNo">049</span>import org.apache.hadoop.hbase.wal.WALKey;<a name="line.49"></a>
-<span class="sourceLineNo">050</span>import org.apache.hadoop.hbase.wal.WALPrettyPrinter;<a name="line.50"></a>
-<span class="sourceLineNo">051</span>import org.apache.hadoop.hbase.wal.WALProvider.Writer;<a name="line.51"></a>
-<span class="sourceLineNo">052</span>import org.apache.hadoop.hbase.wal.WALSplitter;<a name="line.52"></a>
-<span class="sourceLineNo">053</span>import org.apache.hadoop.hdfs.DFSOutputStream;<a name="line.53"></a>
-<span class="sourceLineNo">054</span>import org.apache.hadoop.hdfs.client.HdfsDataOutputStream;<a name="line.54"></a>
-<span class="sourceLineNo">055</span>import org.apache.hadoop.hdfs.protocol.DatanodeInfo;<a name="line.55"></a>
-<span class="sourceLineNo">056</span>import org.apache.htrace.NullScope;<a name="line.56"></a>
-<span class="sourceLineNo">057</span>import org.apache.htrace.Span;<a name="line.57"></a>
-<span class="sourceLineNo">058</span>import org.apache.htrace.Trace;<a name="line.58"></a>
-<span class="sourceLineNo">059</span>import org.apache.htrace.TraceScope;<a name="line.59"></a>
-<span class="sourceLineNo">060</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.60"></a>
-<span class="sourceLineNo">061</span><a name="line.61"></a>
+<span class="sourceLineNo">046</span>import org.apache.hadoop.hbase.wal.AbstractFSWALProvider;<a name="line.46"></a>
+<span class="sourceLineNo">047</span>import org.apache.hadoop.hbase.wal.FSHLogProvider;<a name="line.47"></a>
+<span class="sourceLineNo">048</span>import org.apache.hadoop.hbase.wal.WALEdit;<a name="line.48"></a>
+<span class="sourceLineNo">049</span>import org.apache.hadoop.hbase.wal.WALFactory;<a name="line.49"></a>
+<span class="sourceLineNo">050</span>import org.apache.hadoop.hbase.wal.WALKey;<a name="line.50"></a>
+<span class="sourceLineNo">051</span>import org.apache.hadoop.hbase.wal.WALPrettyPrinter;<a name="line.51"></a>
+<span class="sourceLineNo">052</span>import org.apache.hadoop.hbase.wal.WALProvider.Writer;<a name="line.52"></a>
+<span class="sourceLineNo">053</span>import org.apache.hadoop.hbase.wal.WALSplitter;<a name="line.53"></a>
+<span class="sourceLineNo">054</span>import org.apache.hadoop.hdfs.DFSOutputStream;<a name="line.54"></a>
+<span class="sourceLineNo">055</span>import org.apache.hadoop.hdfs.client.HdfsDataOutputStream;<a name="line.55"></a>
+<span class="sourceLineNo">056</span>import org.apache.hadoop.hdfs.protocol.DatanodeInfo;<a name="line.56"></a>
+<span class="sourceLineNo">057</span>import org.apache.htrace.NullScope;<a name="line.57"></a>
+<span class="sourceLineNo">058</span>import org.apache.htrace.Span;<a name="line.58"></a>
+<span class="sourceLineNo">059</span>import org.apache.htrace.Trace;<a name="line.59"></a>
+<span class="sourceLineNo">060</span>import org.apache.htrace.TraceScope;<a name="line.60"></a>
+<span class="sourceLineNo">061</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.61"></a>
<span class="sourceLineNo">062</span>import org.apache.hadoop.hbase.shaded.com.google.common.annotations.VisibleForTesting;<a name="line.62"></a>
<span class="sourceLineNo">063</span><a name="line.63"></a>
<span class="sourceLineNo">064</span>import com.lmax.disruptor.BlockingWaitStrategy;<a name="line.64"></a>
@@ -805,412 +805,416 @@
<span class="sourceLineNo">797</span> }<a name="line.797"></a>
<span class="sourceLineNo">798</span><a name="line.798"></a>
<span class="sourceLineNo">799</span> final Path baseDir = FSUtils.getWALRootDir(conf);<a name="line.799"></a>
-<span class="sourceLineNo">800</span> final Path archiveDir = new Path(baseDir, HConstants.HREGION_OLDLOGDIR_NAME);<a name="line.800"></a>
-<span class="sourceLineNo">801</span> WALSplitter.split(baseDir, p, archiveDir, fs, conf, WALFactory.getInstance(conf));<a name="line.801"></a>
-<span class="sourceLineNo">802</span> }<a name="line.802"></a>
-<span class="sourceLineNo">803</span><a name="line.803"></a>
-<span class="sourceLineNo">804</span> /**<a name="line.804"></a>
-<span class="sourceLineNo">805</span> * This class is used coordinating two threads holding one thread at a 'safe point' while the<a name="line.805"></a>
-<span class="sourceLineNo">806</span> * orchestrating thread does some work that requires the first thread paused: e.g. holding the WAL<a name="line.806"></a>
-<span class="sourceLineNo">807</span> * writer while its WAL is swapped out from under it by another thread.<a name="line.807"></a>
-<span class="sourceLineNo">808</span> * <p><a name="line.808"></a>
-<span class="sourceLineNo">809</span> * Thread A signals Thread B to hold when it gets to a 'safe point'. Thread A wait until Thread B<a name="line.809"></a>
-<span class="sourceLineNo">810</span> * gets there. When the 'safe point' has been attained, Thread B signals Thread A. Thread B then<a name="line.810"></a>
-<span class="sourceLineNo">811</span> * holds at the 'safe point'. Thread A on notification that Thread B is paused, goes ahead and<a name="line.811"></a>
-<span class="sourceLineNo">812</span> * does the work it needs to do while Thread B is holding. When Thread A is done, it flags B and<a name="line.812"></a>
-<span class="sourceLineNo">813</span> * then Thread A and Thread B continue along on their merry way. Pause and signalling 'zigzags'<a name="line.813"></a>
-<span class="sourceLineNo">814</span> * between the two participating threads. We use two latches -- one the inverse of the other --<a name="line.814"></a>
-<span class="sourceLineNo">815</span> * pausing and signaling when states are achieved.<a name="line.815"></a>
-<span class="sourceLineNo">816</span> * <p><a name="line.816"></a>
-<span class="sourceLineNo">817</span> * To start up the drama, Thread A creates an instance of this class each time it would do this<a name="line.817"></a>
-<span class="sourceLineNo">818</span> * zigzag dance and passes it to Thread B (these classes use Latches so it is one shot only).<a name="line.818"></a>
-<span class="sourceLineNo">819</span> * Thread B notices the new instance (via reading a volatile reference or how ever) and it starts<a name="line.819"></a>
-<span class="sourceLineNo">820</span> * to work toward the 'safe point'. Thread A calls {@link #waitSafePoint(SyncFuture)} when it cannot proceed<a name="line.820"></a>
-<span class="sourceLineNo">821</span> * until the Thread B 'safe point' is attained. Thread A will be held inside in<a name="line.821"></a>
-<span class="sourceLineNo">822</span> * {@link #waitSafePoint(SyncFuture)} until Thread B reaches the 'safe point'. Once there, Thread B frees<a name="line.822"></a>
-<span class="sourceLineNo">823</span> * Thread A by calling {@link #safePointAttained()}. Thread A now knows Thread B is at the 'safe<a name="line.823"></a>
-<span class="sourceLineNo">824</span> * point' and that it is holding there (When Thread B calls {@link #safePointAttained()} it blocks<a name="line.824"></a>
-<span class="sourceLineNo">825</span> * here until Thread A calls {@link #releaseSafePoint()}). Thread A proceeds to do what it needs<a name="line.825"></a>
-<span class="sourceLineNo">826</span> * to do while Thread B is paused. When finished, it lets Thread B lose by calling<a name="line.826"></a>
-<span class="sourceLineNo">827</span> * {@link #releaseSafePoint()} and away go both Threads again.<a name="line.827"></a>
-<span class="sourceLineNo">828</span> */<a name="line.828"></a>
-<span class="sourceLineNo">829</span> static class SafePointZigZagLatch {<a name="line.829"></a>
-<span class="sourceLineNo">830</span> /**<a name="line.830"></a>
-<span class="sourceLineNo">831</span> * Count down this latch when safe point attained.<a name="line.831"></a>
-<span class="sourceLineNo">832</span> */<a name="line.832"></a>
-<span class="sourceLineNo">833</span> private volatile CountDownLatch safePointAttainedLatch = new CountDownLatch(1);<a name="line.833"></a>
+<span class="sourceLineNo">800</span> Path archiveDir = new Path(baseDir, HConstants.HREGION_OLDLOGDIR_NAME);<a name="line.800"></a>
+<span class="sourceLineNo">801</span> if (conf.getBoolean(AbstractFSWALProvider.SEPARATE_OLDLOGDIR,<a name="line.801"></a>
+<span class="sourceLineNo">802</span> AbstractFSWALProvider.DEFAULT_SEPARATE_OLDLOGDIR)) {<a name="line.802"></a>
+<span class="sourceLineNo">803</span> archiveDir = new Path(archiveDir, p.getName());<a name="line.803"></a>
+<span class="sourceLineNo">804</span> }<a name="line.804"></a>
+<span class="sourceLineNo">805</span> WALSplitter.split(baseDir, p, archiveDir, fs, conf, WALFactory.getInstance(conf));<a name="line.805"></a>
+<span class="sourceLineNo">806</span> }<a name="line.806"></a>
+<span class="sourceLineNo">807</span><a name="line.807"></a>
+<span class="sourceLineNo">808</span> /**<a name="line.808"></a>
+<span class="sourceLineNo">809</span> * This class is used coordinating two threads holding one thread at a 'safe point' while the<a name="line.809"></a>
+<span class="sourceLineNo">810</span> * orchestrating thread does some work that requires the first thread paused: e.g. holding the WAL<a name="line.810"></a>
+<span class="sourceLineNo">811</span> * writer while its WAL is swapped out from under it by another thread.<a name="line.811"></a>
+<span class="sourceLineNo">812</span> * <p><a name="line.812"></a>
+<span class="sourceLineNo">813</span> * Thread A signals Thread B to hold when it gets to a 'safe point'. Thread A wait until Thread B<a name="line.813"></a>
+<span class="sourceLineNo">814</span> * gets there. When the 'safe point' has been attained, Thread B signals Thread A. Thread B then<a name="line.814"></a>
+<span class="sourceLineNo">815</span> * holds at the 'safe point'. Thread A on notification that Thread B is paused, goes ahead and<a name="line.815"></a>
+<span class="sourceLineNo">816</span> * does the work it needs to do while Thread B is holding. When Thread A is done, it flags B and<a name="line.816"></a>
+<span class="sourceLineNo">817</span> * then Thread A and Thread B continue along on their merry way. Pause and signalling 'zigzags'<a name="line.817"></a>
+<span class="sourceLineNo">818</span> * between the two participating threads. We use two latches -- one the inverse of the other --<a name="line.818"></a>
+<span class="sourceLineNo">819</span> * pausing and signaling when states are achieved.<a name="line.819"></a>
+<span class="sourceLineNo">820</span> * <p><a name="line.820"></a>
+<span class="sourceLineNo">821</span> * To start up the drama, Thread A creates an instance of this class each time it would do this<a name="line.821"></a>
+<span class="sourceLineNo">822</span> * zigzag dance and passes it to Thread B (these classes use Latches so it is one shot only).<a name="line.822"></a>
+<span class="sourceLineNo">823</span> * Thread B notices the new instance (via reading a volatile reference or how ever) and it starts<a name="line.823"></a>
+<span class="sourceLineNo">824</span> * to work toward the 'safe point'. Thread A calls {@link #waitSafePoint(SyncFuture)} when it cannot proceed<a name="line.824"></a>
+<span class="sourceLineNo">825</span> * until the Thread B 'safe point' is attained. Thread A will be held inside in<a name="line.825"></a>
+<span class="sourceLineNo">826</span> * {@link #waitSafePoint(SyncFuture)} until Thread B reaches the 'safe point'. Once there, Thread B frees<a name="line.826"></a>
+<span class="sourceLineNo">827</span> * Thread A by calling {@link #safePointAttained()}. Thread A now knows Thread B is at the 'safe<a name="line.827"></a>
+<span class="sourceLineNo">828</span> * point' and that it is holding there (When Thread B calls {@link #safePointAttained()} it blocks<a name="line.828"></a>
+<span class="sourceLineNo">829</span> * here until Thread A calls {@link #releaseSafePoint()}). Thread A proceeds to do what it needs<a name="line.829"></a>
+<span class="sourceLineNo">830</span> * to do while Thread B is paused. When finished, it lets Thread B lose by calling<a name="line.830"></a>
+<span class="sourceLineNo">831</span> * {@link #releaseSafePoint()} and away go both Threads again.<a name="line.831"></a>
+<span class="sourceLineNo">832</span> */<a name="line.832"></a>
+<span class="sourceLineNo">833</span> static class SafePointZigZagLatch {<a name="line.833"></a>
<span class="sourceLineNo">834</span> /**<a name="line.834"></a>
-<span class="sourceLineNo">835</span> * Latch to wait on. Will be released when we can proceed.<a name="line.835"></a>
+<span class="sourceLineNo">835</span> * Count down this latch when safe point attained.<a name="line.835"></a>
<span class="sourceLineNo">836</span> */<a name="line.836"></a>
-<span class="sourceLineNo">837</span> private volatile CountDownLatch safePointReleasedLatch = new CountDownLatch(1);<a name="line.837"></a>
-<span class="sourceLineNo">838</span><a name="line.838"></a>
-<span class="sourceLineNo">839</span> private void checkIfSyncFailed(SyncFuture syncFuture) throws FailedSyncBeforeLogCloseException {<a name="line.839"></a>
-<span class="sourceLineNo">840</span> if (syncFuture.isThrowable()) {<a name="line.840"></a>
-<span class="sourceLineNo">841</span> throw new FailedSyncBeforeLogCloseException(syncFuture.getThrowable());<a name="line.841"></a>
-<span class="sourceLineNo">842</span> }<a name="line.842"></a>
-<span class="sourceLineNo">843</span> }<a name="line.843"></a>
-<span class="sourceLineNo">844</span><a name="line.844"></a>
-<span class="sourceLineNo">845</span> /**<a name="line.845"></a>
-<span class="sourceLineNo">846</span> * For Thread A to call when it is ready to wait on the 'safe point' to be attained. Thread A<a name="line.846"></a>
-<span class="sourceLineNo">847</span> * will be held in here until Thread B calls {@link #safePointAttained()}<a name="line.847"></a>
-<span class="sourceLineNo">848</span> * @param syncFuture We need this as barometer on outstanding syncs. If it comes home with an<a name="line.848"></a>
-<span class="sourceLineNo">849</span> * exception, then something is up w/ our syncing.<a name="line.849"></a>
-<span class="sourceLineNo">850</span> * @return The passed <code>syncFuture</code><a name="line.850"></a>
-<span class="sourceLineNo">851</span> */<a name="line.851"></a>
-<span class="sourceLineNo">852</span> SyncFuture waitSafePoint(SyncFuture syncFuture) throws InterruptedException,<a name="line.852"></a>
-<span class="sourceLineNo">853</span> FailedSyncBeforeLogCloseException {<a name="line.853"></a>
-<span class="sourceLineNo">854</span> while (!this.safePointAttainedLatch.await(1, TimeUnit.MILLISECONDS)) {<a name="line.854"></a>
-<span class="sourceLineNo">855</span> checkIfSyncFailed(syncFuture);<a name="line.855"></a>
-<span class="sourceLineNo">856</span> }<a name="line.856"></a>
-<span class="sourceLineNo">857</span> checkIfSyncFailed(syncFuture);<a name="line.857"></a>
-<span class="sourceLineNo">858</span> return syncFuture;<a name="line.858"></a>
-<span class="sourceLineNo">859</span> }<a name="line.859"></a>
-<span class="sourceLineNo">860</span><a name="line.860"></a>
-<span class="sourceLineNo">861</span> /**<a name="line.861"></a>
-<span class="sourceLineNo">862</span> * Called by Thread B when it attains the 'safe point'. In this method, Thread B signals Thread<a name="line.862"></a>
-<span class="sourceLineNo">863</span> * A it can proceed. Thread B will be held in here until {@link #releaseSafePoint()} is called<a name="line.863"></a>
-<span class="sourceLineNo">864</span> * by Thread A.<a name="line.864"></a>
-<span class="sourceLineNo">865</span> */<a name="line.865"></a>
-<span class="sourceLineNo">866</span> void safePointAttained() throws InterruptedException {<a name="line.866"></a>
-<span class="sourceLineNo">867</span> this.safePointAttainedLatch.countDown();<a name="line.867"></a>
-<span class="sourceLineNo">868</span> this.safePointReleasedLatch.await();<a name="line.868"></a>
-<span class="sourceLineNo">869</span> }<a name="line.869"></a>
-<span class="sourceLineNo">870</span><a name="line.870"></a>
-<span class="sourceLineNo">871</span> /**<a name="line.871"></a>
-<span class="sourceLineNo">872</span> * Called by Thread A when it is done with the work it needs to do while Thread B is halted.<a name="line.872"></a>
-<span class="sourceLineNo">873</span> * This will release the Thread B held in a call to {@link #safePointAttained()}<a name="line.873"></a>
-<span class="sourceLineNo">874</span> */<a name="line.874"></a>
-<span class="sourceLineNo">875</span> void releaseSafePoint() {<a name="line.875"></a>
-<span class="sourceLineNo">876</span> this.safePointReleasedLatch.countDown();<a name="line.876"></a>
-<span class="sourceLineNo">877</span> }<a name="line.877"></a>
-<span class="sourceLineNo">878</span><a name="line.878"></a>
-<span class="sourceLineNo">879</span> /**<a name="line.879"></a>
-<span class="sourceLineNo">880</span> * @return True is this is a 'cocked', fresh instance, and not one that has already fired.<a name="line.880"></a>
-<span class="sourceLineNo">881</span> */<a name="line.881"></a>
-<span class="sourceLineNo">882</span> boolean isCocked() {<a name="line.882"></a>
-<span class="sourceLineNo">883</span> return this.safePointAttainedLatch.getCount() > 0<a name="line.883"></a>
-<span class="sourceLineNo">884</span> && this.safePointReleasedLatch.getCount() > 0;<a name="line.884"></a>
-<span class="sourceLineNo">885</span> }<a name="line.885"></a>
-<span class="sourceLineNo">886</span> }<a name="line.886"></a>
-<span class="sourceLineNo">887</span><a name="line.887"></a>
-<span class="sourceLineNo">888</span> /**<a name="line.888"></a>
-<span class="sourceLineNo">889</span> * Handler that is run by the disruptor ringbuffer consumer. Consumer is a SINGLE<a name="line.889"></a>
-<span class="sourceLineNo">890</span> * 'writer/appender' thread. Appends edits and starts up sync runs. Tries its best to batch up<a name="line.890"></a>
-<span class="sourceLineNo">891</span> * syncs. There is no discernible benefit batching appends so we just append as they come in<a name="line.891"></a>
-<span class="sourceLineNo">892</span> * because it simplifies the below implementation. See metrics for batching effectiveness (In<a name="line.892"></a>
-<span class="sourceLineNo">893</span> * measurement, at 100 concurrent handlers writing 1k, we are batching > 10 appends and 10 handler<a name="line.893"></a>
-<span class="sourceLineNo">894</span> * sync invocations for every actual dfsclient sync call; at 10 concurrent handlers, YMMV).<a name="line.894"></a>
-<span class="sourceLineNo">895</span> * <p><a name="line.895"></a>
-<span class="sourceLineNo">896</span> * Herein, we have an array into which we store the sync futures as they come in. When we have a<a name="line.896"></a>
-<span class="sourceLineNo">897</span> * 'batch', we'll then pass what we have collected to a SyncRunner thread to do the filesystem<a name="line.897"></a>
-<span class="sourceLineNo">898</span> * sync. When it completes, it will then call {@link SyncFuture#done(long, Throwable)} on each of<a name="line.898"></a>
-<span class="sourceLineNo">899</span> * SyncFutures in the batch to release blocked Handler threads.<a name="line.899"></a>
-<span class="sourceLineNo">900</span> * <p><a name="line.900"></a>
-<span class="sourceLineNo">901</span> * I've tried various effects to try and make latencies low while keeping throughput high. I've<a name="line.901"></a>
-<span class="sourceLineNo">902</span> * tried keeping a single Queue of SyncFutures in this class appending to its tail as the syncs<a name="line.902"></a>
-<span class="sourceLineNo">903</span> * coming and having sync runner threads poll off the head to 'finish' completed SyncFutures. I've<a name="line.903"></a>
-<span class="sourceLineNo">904</span> * tried linkedlist, and various from concurrent utils whether LinkedBlockingQueue or<a name="line.904"></a>
-<span class="sourceLineNo">905</span> * ArrayBlockingQueue, etc. The more points of synchronization, the more 'work' (according to<a name="line.905"></a>
-<span class="sourceLineNo">906</span> * 'perf stats') that has to be done; small increases in stall percentages seem to have a big<a name="line.906"></a>
-<span class="sourceLineNo">907</span> * impact on throughput/latencies. The below model where we have an array into which we stash the<a name="line.907"></a>
-<span class="sourceLineNo">908</span> * syncs and then hand them off to the sync thread seemed like a decent compromise. See HBASE-8755<a name="line.908"></a>
-<span class="sourceLineNo">909</span> * for more detail.<a name="line.909"></a>
-<span class="sourceLineNo">910</span> */<a name="line.910"></a>
-<span class="sourceLineNo">911</span> class RingBufferEventHandler implements EventHandler<RingBufferTruck>, LifecycleAware {<a name="line.911"></a>
-<span class="sourceLineNo">912</span> private final SyncRunner[] syncRunners;<a name="line.912"></a>
-<span class="sourceLineNo">913</span> private final SyncFuture[] syncFutures;<a name="line.913"></a>
-<span class="sourceLineNo">914</span> // Had 'interesting' issues when this was non-volatile. On occasion, we'd not pass all<a name="line.914"></a>
-<span class="sourceLineNo">915</span> // syncFutures to the next sync'ing thread.<a name="line.915"></a>
-<span class="sourceLineNo">916</span> private volatile int syncFuturesCount = 0;<a name="line.916"></a>
-<span class="sourceLineNo">917</span> private volatile SafePointZigZagLatch zigzagLatch;<a name="line.917"></a>
-<span class="sourceLineNo">918</span> /**<a name="line.918"></a>
-<span class="sourceLineNo">919</span> * Set if we get an exception appending or syncing so that all subsequence appends and syncs on<a name="line.919"></a>
-<span class="sourceLineNo">920</span> * this WAL fail until WAL is replaced.<a name="line.920"></a>
-<span class="sourceLineNo">921</span> */<a name="line.921"></a>
-<span class="sourceLineNo">922</span> private Exception exception = null;<a name="line.922"></a>
-<span class="sourceLineNo">923</span> /**<a name="line.923"></a>
-<span class="sourceLineNo">924</span> * Object to block on while waiting on safe point.<a name="line.924"></a>
+<span class="sourceLineNo">837</span> private volatile CountDownLatch safePointAttainedLatch = new CountDownLatch(1);<a name="line.837"></a>
+<span class="sourceLineNo">838</span> /**<a name="line.838"></a>
+<span class="sourceLineNo">839</span> * Latch to wait on. Will be released when we can proceed.<a name="line.839"></a>
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+<span class="sourceLineNo">1146</span> System.err.println(" --dump Dump textual representation of passed one or more files");<a name="line.1146"></a>
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+<span class="sourceLineNo">1150</span> System.err.println(<a name="line.1150"></a>
+<span class="sourceLineNo">1151</span> " For example: " + "FSHLog --split hdfs://example.com:9000/hbase/WALs/DIR");<a name="line.1151"></a>
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+<span class="sourceLineNo">1154</span> /**<a name="line.1154"></a>
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+<span class="sourceLineNo">1168</span> LOG.fatal(<a name="line.1168"></a>
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