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From chir...@apache.org
Subject svn commit: r475708 - /incubator/activemq/site/how-do-durable-queues-and-topics-work.html
Date Thu, 16 Nov 2006 12:23:49 GMT
Author: chirino
Date: Thu Nov 16 04:23:48 2006
New Revision: 475708

URL: http://svn.apache.org/viewvc?view=rev&rev=475708
Log:
Latest export from confluence

Modified:
    incubator/activemq/site/how-do-durable-queues-and-topics-work.html

Modified: incubator/activemq/site/how-do-durable-queues-and-topics-work.html
URL: http://svn.apache.org/viewvc/incubator/activemq/site/how-do-durable-queues-and-topics-work.html?view=diff&rev=475708&r1=475707&r2=475708
==============================================================================
--- incubator/activemq/site/how-do-durable-queues-and-topics-work.html (original)
+++ incubator/activemq/site/how-do-durable-queues-and-topics-work.html Thu Nov 16 04:23:48
2006
@@ -252,8 +252,7 @@
 <!--          
             <div class="pagetitle">How do durable queues and topics work</div>
 -->
-            <DIV class="wiki-content">
-<P>Durable queues keep messages around persistently for any suitable consumer to consume
them. Durable queues do not need to concern themselves with which consumer is going to consume
the messages at some point in the future. There is just one copy of a message that any consumer
in the future can consume.</P>
+            <DIV class="wiki-content"><P>Durable queues keep messages around
persistently for any suitable consumer to consume them. Durable queues do not need to concern
themselves with which consumer is going to consume the messages at some point in the future.
There is just one copy of a message that any consumer in the future can consume.</P>
 
 <P>Durable topics however are different as they must logically persist an instance
of each suitable message for every durable consumer - since each durable consumer gets their
own copy of the message.</P>
 
@@ -261,7 +260,7 @@
 
 <P>When S restarts at D2, the publisher sends M6 and M7. Now S will receive M4, M5
followed by M6 and M7 and all future messages. i.e. S will receive all messages from M1..M7.</P>
 
-<P>This is the difference between durable and non-durable publishing. If S were a non-durable
pubisher then it would only have received M1, M2, M3 and M6, M7 - not M4 and M5. i.e. because
the subscription is durable, S will receive every message sent to T whether the subscriber
is running or not. For non-durable topics, only messages delivered to the topic T when S is
running are delivered.</P>
+<P>This is the difference between durable and non-durable consuming. If S were a non-durable
consumer then it would only have received M1, M2, M3 and M6, M7 - not M4 and M5. i.e. because
the subscription is durable, S will receive every message sent to T whether the subscriber
is running or not. For non-durable topics, only messages delivered to the topic T when S is
running are delivered.</P>
 
 <P>So for durable topic subscription, the JMS provider needs to be able to identify
S when it shuts down and later on in the future reconnects, so it can know what messages to
send to it while it was not running. JMS specification dictates that the identification of
S is done by a combination of the clientID and the durable subscriber name. This is so that
the JMS connection S uses can have many different durable subscriptions on different topics
or on the same topic with different selectors - yet the JMS provider can know which message
for which subscription to keep around for it.</P>
 
@@ -275,8 +274,9 @@
     </DIV>
     <DIV id="site-footer">
           Added by     <A href="http://goopen.org/confluence/users/viewuserprofile.action?username=jstrachan">James
Strachan</A>,
-    last edited by     <A href="http://goopen.org/confluence/users/viewuserprofile.action?username=jstrachan">James
Strachan</A> on May 23, 2005
-                  
+    last edited by     <A href="http://goopen.org/confluence/users/viewuserprofile.action?username=tabish121">Timothy
Bish</A> on Nov 21, 2006
+                  &nbsp;(<A href="http://goopen.org/confluence/pages/diffpages.action?pageId=216&originalId=15124">view
change</A>)
+              
       (<A href="http://goopen.org/confluence/pages/editpage.action?pageId=216">edit
page</A>)
     </DIV>
 



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