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<div class="subTitle">org.apache.hadoop.hdfs.shortcircuit</div>
<h2 title="Class DfsClientShm" class="title">Class DfsClientShm</h2>
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<li><a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html" title="class in org.apache.hadoop.hdfs.shortcircuit">org.apache.hadoop.hdfs.shortcircuit.ShortCircuitShm</a></li>
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<li>org.apache.hadoop.hdfs.shortcircuit.DfsClientShm</li>
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<dt>All Implemented Interfaces:</dt>
<dd>org.apache.hadoop.net.unix.DomainSocketWatcher.Handler</dd>
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<pre>public class <span class="typeNameLabel">DfsClientShm</span>
extends <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html" title="class in org.apache.hadoop.hdfs.shortcircuit">ShortCircuitShm</a>
implements org.apache.hadoop.net.unix.DomainSocketWatcher.Handler</pre>
<div class="block">DfsClientShm is a subclass of ShortCircuitShm which is used by the
DfsClient.
When the UNIX domain socket associated with this shared memory segment
closes unexpectedly, we mark the slots inside this segment as disconnected.
ShortCircuitReplica objects that contain disconnected slots are stale,
and will not be used to service new reads or mmap operations.
However, in-progress read or mmap operations will continue to proceed.
Once the last slot is deallocated, the segment can be safely munmapped.
Slots may also become stale because the associated replica has been deleted
on the DataNode. In this case, the DataNode will clear the 'valid' bit.
The client will then see these slots as stale (see
#{ShortCircuitReplica#isStale}).</div>
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<h3>Nested classes/interfaces inherited from class&nbsp;org.apache.hadoop.hdfs.shortcircuit.<a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html" title="class in org.apache.hadoop.hdfs.shortcircuit">ShortCircuitShm</a></h3>
<code><a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.ShmId.html" title="class in org.apache.hadoop.hdfs.shortcircuit">ShortCircuitShm.ShmId</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.Slot.html" title="class in org.apache.hadoop.hdfs.shortcircuit">ShortCircuitShm.Slot</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.SlotId.html" title="class in org.apache.hadoop.hdfs.shortcircuit">ShortCircuitShm.SlotId</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.SlotIterator.html" title="class in org.apache.hadoop.hdfs.shortcircuit">ShortCircuitShm.SlotIterator</a></code></li>
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<code><a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html#BYTES_PER_SLOT">BYTES_PER_SLOT</a></code></li>
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<th class="colFirst" scope="col">Modifier and Type</th>
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<td class="colFirst"><code>org.apache.hadoop.hdfs.shortcircuit.DfsClientShmManager.EndpointShmManager</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/DfsClientShm.html#getEndpointShmManager--">getEndpointShmManager</a></span>()</code>&nbsp;</td>
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<tr id="i1" class="rowColor">
<td class="colFirst"><code>org.apache.hadoop.hdfs.net.DomainPeer</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/DfsClientShm.html#getPeer--">getPeer</a></span>()</code>&nbsp;</td>
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<td class="colFirst"><code>boolean</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/DfsClientShm.html#handle-org.apache.hadoop.net.unix.DomainSocket-">handle</a></span>(org.apache.hadoop.net.unix.DomainSocket&nbsp;sock)</code>
<div class="block">Handle the closure of the UNIX domain socket associated with this shared
memory segment by marking this segment as stale.</div>
</td>
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<tr id="i3" class="rowColor">
<td class="colFirst"><code>boolean</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/DfsClientShm.html#isDisconnected--">isDisconnected</a></span>()</code>
<div class="block">Determine if the shared memory segment is disconnected from the DataNode.</div>
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<code><a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html#allocAndRegisterSlot-org.apache.hadoop.hdfs.ExtendedBlockId-">allocAndRegisterSlot</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html#free--">free</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html#getShmId--">getShmId</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html#getSlot-int-">getSlot</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html#isEmpty--">isEmpty</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html#isFull--">isFull</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html#registerSlot-int-org.apache.hadoop.hdfs.ExtendedBlockId-">registerSlot</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html#slotIterator--">slotIterator</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html#toString--">toString</a>, <a href="../../../../../org/apache/hadoop/hdfs/shortcircuit/ShortCircuitShm.html#unregisterSlot-int-">unregisterSlot</a></code></li>
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<h4>getEndpointShmManager</h4>
<pre>public&nbsp;org.apache.hadoop.hdfs.shortcircuit.DfsClientShmManager.EndpointShmManager&nbsp;getEndpointShmManager()</pre>
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<h4>getPeer</h4>
<pre>public&nbsp;org.apache.hadoop.hdfs.net.DomainPeer&nbsp;getPeer()</pre>
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<pre>public&nbsp;boolean&nbsp;isDisconnected()</pre>
<div class="block">Determine if the shared memory segment is disconnected from the DataNode.
This must be called with the DfsClientShmManager lock held.</div>
<dl>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>True if the shared memory segment is stale.</dd>
</dl>
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<h4>handle</h4>
<pre>public&nbsp;boolean&nbsp;handle(org.apache.hadoop.net.unix.DomainSocket&nbsp;sock)</pre>
<div class="block">Handle the closure of the UNIX domain socket associated with this shared
memory segment by marking this segment as stale.
If there are no slots associated with this shared memory segment, it will
be freed immediately in this function.</div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code>handle</code>&nbsp;in interface&nbsp;<code>org.apache.hadoop.net.unix.DomainSocketWatcher.Handler</code></dd>
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