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   <title>Persistent Sessions: The L2 Session Data Cache</title><link rel="stylesheet" type="text/css" href="css/docbook.css"><meta name="generator" content="DocBook XSL Stylesheets V1.79.1"><meta name="keywords" content="jetty, servlet, servlet-api, cometd, http, websocket, eclipse, maven, java, server, software"><link rel="home" href="index.html" title="Jetty"><link rel="up" href="session-management.html" title="Chapter&nbsp;10.&nbsp;Session Management"><link rel="prev" href="configuring-sessions-gcloud.html" title="Persistent Sessions: Google Cloud DataStore"><link rel="next" href="sessions-usecases.html" title="Session Use Cases"><link xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" rel="shortcut icon" href="images/favicon.ico"><link rel="stylesheet" href="css/highlighter/foundation.css"><script src="js/highlight.pack.js"></script><script>
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      </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="session-configuration-memcachedsessiondatastore"></a>Persistent Sessions: The L2 Session Data Cache</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="section"><a href="session-configuration-memcachedsessiondatastore.html#_memcachedsessiondatamap">MemcachedSessionDataMap</a></span></dt></dl></div><p>If your chosen persistence technology is slow, it can be helpful to locally cache the session data.
The <code class="literal">CachingSessionDataStore</code> is a special type of <code class="literal">SessionDataStore</code> that locally caches session data, which makes reads faster. It writes-through to your chosen type of <code class="literal">SessionDataStore</code> when session data changes.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_memcachedsessiondatamap"></a>MemcachedSessionDataMap</h3></div></div></div><p>The <code class="literal">MemcachedSessionDataMap</code> uses <code class="literal">memcached</code> to perform caching.</p><p>To enable it with the Jetty distribution, enable the <code class="literal">session-store-cache</code> <a class="link" href="startup-modules.html" title="Managing Startup Modules">module</a>, along with your chosen <code class="literal">session-store-xxxx</code> module, and optionally the <code class="literal">session-cache-hash</code> or <code class="literal">session-cache-null</code> modules.</p><p>After enabling, the <code class="literal">$jetty.base/start.d/session-store-cache.ini</code> file will be generated:</p><div class="screenexample"><pre class="screen">--module=session-store-cache


## Session Data Cache type: xmemcached
session-data-cache=xmemcached
#jetty.session.memcached.host=localhost
#jetty.session.memcached.port=11211
#jetty.session.memcached.expirySec=
#jetty.session.memcached.heartbeats=true</pre></div><p>The configuration properties are:</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">jetty.session.memcached.host</span></dt><dd>Default value is <code class="literal">localhost</code>.
This is the host on which the memcached server resides.</dd><dt><span class="term">jetty.session.memcached.port</span></dt><dd>Default value is <code class="literal">11211</code>.
This is the port on which the memcached server is listening.</dd><dt><span class="term">jetty.session.memcached.expirySec</span></dt><dd>Default value <code class="literal">0</code>.
This is the length of time in seconds that an item can remain in the memcached cache, where 0 indicates indefinitely.</dd><dt><span class="term">jetty.session.memcached.heartbeats</span></dt><dd>Default value <code class="literal">true</code>.
Whether or not the memcached system should generate heartbeats.</dd></dl></div></div></div><script type="text/javascript">
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