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List:       activemq-commits
Subject:    svn commit: r856522 - in /websites/production/activemq/content: cache/main.pageCache how-can-i-suppo
From:       buildbot () apache ! org
Date:       2013-03-29 18:23:07
Message-ID: 20130329182307.46CBD23889D7 () eris ! apache ! org
[Download RAW message or body]

Author: buildbot
Date: Fri Mar 29 18:23:06 2013
New Revision: 856522

Log:
Production update by buildbot for activemq

Modified:
    websites/production/activemq/content/cache/main.pageCache
    websites/production/activemq/content/how-can-i-support-priority-queues.html

Modified: websites/production/activemq/content/cache/main.pageCache
==============================================================================
Binary files - no diff available.

Modified: websites/production/activemq/content/how-can-i-support-priority-queues.html
==============================================================================
--- websites/production/activemq/content/how-can-i-support-priority-queues.html \
                (original)
+++ websites/production/activemq/content/how-can-i-support-priority-queues.html Fri \
Mar 29 18:23:06 2013 @@ -89,7 +89,19 @@
 </pre>
 </div></div>
 
-<p>The full range of priority values (0-9) are supported by the <a shape="rect" \
href="jdbc-support.html" title="JDBC Support">JDBC</a> message store. For <a \
shape="rect" href="kahadb.html" title="KahaDB">KahaDB</a> three priority levels are \
supported, Low (&lt;5), Default (=5) and High (&gt;5).</p> +<p>The full range of \
priority values (0-9) are supported by the <a shape="rect" href="jdbc-support.html" \
title="JDBC Support">JDBC</a> message store. For <a shape="rect" href="kahadb.html" \
title="KahaDB">KahaDB</a> three priority categories are supported, Low (&lt; 4), \
Default (= 4) and High (&gt; 4).</p> +
+<p>Since the message cursors (and client side) implement strict ordering of \
priorities, it's possible to observe strict priority ordering if message dispatching \
can happen from the cache and not have to hit the disk (i.e., your consumers are fast \
enough to keep up with producers), or if you're using non-persistent messages that \
never have to flush to disk (which happens by default using the \
FilePendingMessageCursor). However, once you hit a situation where consumers are \
slow, or producers are just significantly faster, you'll observe that the cache will \
fill up (possibly with lower priority messages) while higher priority messages get \
stuck on disk and not available until they're paged in. In this case, you can make a \
decision to tradeoff optimized message dispatching for priority enforcement. You can \
disable the cache, message expiration check, and lower you consumer prefetch to 1 to \
ensure getting the high priority messages from the store ahead of lower priority \
messages:<  /p>
+
+<div class="code panel" style="border-width: 1px;"><div class="codeContent \
panelContent"> +<pre class="code-java">
+ &lt;destinationPolicy&gt;
+   &lt;policyMap&gt;
+     &lt;policyEntries&gt;
+       &lt;policyEntry queue=<span class="code-quote">"&gt;"</span> \
prioritizedMessages=<span class="code-quote">"<span \
class="code-keyword">true</span>"</span> useCache=<span class="code-quote">"<span \
class="code-keyword">false</span>"</span> expireMessagesPeriod=<span \
class="code-quote">"0"</span> queuePrefetch=<span class="code-quote">"1"</span> /&gt; \
+    ... +</pre>
+</div></div>
 
 <h3><a shape="rect" \
name="HowcanIsupportpriorityqueues-Alternativestrategies"></a>Alternative \
strategies</h3>  <h4><a shape="rect" \
name="HowcanIsupportpriorityqueues-UseSelectors"></a>Use Selectors</h4> @@ -118,7 \
+130,6 @@ JMSPriority &gt;= 4  
 <p>To do this use the <a shape="rect" class="external-link" \
href="http://activemq.apache.org/camel/resequencer.html">Resequencer</a> from the <a \
shape="rect" href="enterprise-integration-patterns.html" title="Enterprise \
Integration Patterns">Enterprise Integration Patterns</a></p>  
-
           </div>
         </td>
         <td valign="top">


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