svn commit: r856522 - in /websites/production/activemq/content: cache/main.pageCache how-can-i-support-priority-queues.html

[buildbot]

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">