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
+ (<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>
