| <!DOCTYPE html> |
| <!-- |
| - |
| - Licensed to the Apache Software Foundation (ASF) under one |
| - or more contributor license agreements. See the NOTICE file |
| - distributed with this work for additional information |
| - regarding copyright ownership. The ASF licenses this file |
| - to you under the Apache License, Version 2.0 (the |
| - "License"); you may not use this file except in compliance |
| - with the License. You may obtain a copy of the License at |
| - |
| - http://www.apache.org/licenses/LICENSE-2.0 |
| - |
| - Unless required by applicable law or agreed to in writing, |
| - software distributed under the License is distributed on an |
| - "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| - KIND, either express or implied. See the License for the |
| - specific language governing permissions and limitations |
| - under the License. |
| - |
| --> |
| <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> |
| <head> |
| <title>9.4. Handing Undeliverable Messages - Apache Qpid™</title> |
| <meta http-equiv="X-UA-Compatible" content="IE=edge"/> |
| <meta name="viewport" content="width=device-width, initial-scale=1.0"/> |
| <link rel="stylesheet" href="/site.css" type="text/css" async="async"/> |
| <link rel="stylesheet" href="/deferred.css" type="text/css" defer="defer"/> |
| <script type="text/javascript">var _deferredFunctions = [];</script> |
| <script type="text/javascript" src="/deferred.js" defer="defer"></script> |
| <!--[if lte IE 8]> |
| <link rel="stylesheet" href="/ie.css" type="text/css"/> |
| <script type="text/javascript" src="/html5shiv.js"></script> |
| <![endif]--> |
| |
| <!-- Redirects for `go get` and godoc.org --> |
| <meta name="go-import" |
| content="qpid.apache.org git https://gitbox.apache.org/repos/asf/qpid-proton.git"/> |
| <meta name="go-source" |
| content="qpid.apache.org |
| https://github.com/apache/qpid-proton/blob/go1/README.md |
| https://github.com/apache/qpid-proton/tree/go1{/dir} |
| https://github.com/apache/qpid-proton/blob/go1{/dir}/{file}#L{line}"/> |
| </head> |
| <body> |
| <div id="-content"> |
| <div id="-top" class="panel"> |
| <a id="-menu-link"><img width="16" height="16" src="" alt="Menu"/></a> |
| |
| <a id="-search-link"><img width="22" height="16" src="" alt="Search"/></a> |
| |
| <ul id="-global-navigation"> |
| <li><a id="-logotype" href="/index.html">Apache Qpid<sup>™</sup></a></li> |
| <li><a href="/documentation.html">Documentation</a></li> |
| <li><a href="/download.html">Download</a></li> |
| <li><a href="/discussion.html">Discussion</a></li> |
| </ul> |
| </div> |
| |
| <div id="-menu" class="panel" style="display: none;"> |
| <div class="flex"> |
| <section> |
| <h3>Project</h3> |
| |
| <ul> |
| <li><a href="/overview.html">Overview</a></li> |
| <li><a href="/components/index.html">Components</a></li> |
| <li><a href="/releases/index.html">Releases</a></li> |
| </ul> |
| </section> |
| |
| <section> |
| <h3>Messaging APIs</h3> |
| |
| <ul> |
| <li><a href="/proton/index.html">Qpid Proton</a></li> |
| <li><a href="/components/jms/index.html">Qpid JMS</a></li> |
| <li><a href="/components/messaging-api/index.html">Qpid Messaging API</a></li> |
| </ul> |
| </section> |
| |
| <section> |
| <h3>Servers and tools</h3> |
| |
| <ul> |
| <li><a href="/components/broker-j/index.html">Broker-J</a></li> |
| <li><a href="/components/cpp-broker/index.html">C++ broker</a></li> |
| <li><a href="/components/dispatch-router/index.html">Dispatch router</a></li> |
| </ul> |
| </section> |
| |
| <section> |
| <h3>Resources</h3> |
| |
| <ul> |
| <li><a href="/dashboard.html">Dashboard</a></li> |
| <li><a href="https://cwiki.apache.org/confluence/display/qpid/Index">Wiki</a></li> |
| <li><a href="/resources.html">More resources</a></li> |
| </ul> |
| </section> |
| </div> |
| </div> |
| |
| <div id="-search" class="panel" style="display: none;"> |
| <form action="http://www.google.com/search" method="get"> |
| <input type="hidden" name="sitesearch" value="qpid.apache.org"/> |
| <input type="text" name="q" maxlength="255" autofocus="autofocus" tabindex="1"/> |
| <button type="submit">Search</button> |
| <a href="/search.html">More ways to search</a> |
| </form> |
| </div> |
| |
| <div id="-middle" class="panel"> |
| <ul id="-path-navigation"><li><a href="/index.html">Home</a></li><li><a href="/releases/index.html">Releases</a></li><li><a href="/releases/qpid-broker-j-7.1.9/index.html">Qpid Broker-J 7.1.9</a></li><li><a href="/releases/qpid-broker-j-7.1.9/book/index.html">Apache Qpid Broker-J</a></li><li>9.4. Handing Undeliverable Messages</li></ul> |
| |
| <div id="-middle-content"> |
| <div class="docbook"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">9.4. Handing Undeliverable Messages</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="Java-Broker-Runtime-Transaction-Timeout.html">Prev</a> </td><th align="center" width="60%">Chapter 9. Runtime</th><td align="right" width="20%"> <a accesskey="n" href="Java-Broker-Runtime-Close-Connection-When-No-Route.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Java-Broker-Runtime-Handling-Undeliverable-Messages"></a>9.4. Handing Undeliverable Messages</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Handling-Undeliverable-Messages-Introduction"></a>9.4.1. Introduction</h3></div></div></div><p> Messages that cannot be delivered successfully to a consumer (for instance, because the |
| client is using a transacted session and rolls-back the transaction) can be made available on |
| the queue again and then subsequently be redelivered, depending on the precise session |
| acknowledgement mode and messaging model used by the application. This is normally desirable |
| behaviour that contributes to the ability of a system to withstand unexpected errors. However, it |
| leaves open the possibility for a message to be repeatedly redelivered (potentially indefinitely), |
| consuming system resources and preventing the delivery of other messages. Such undeliverable |
| messages are sometimes known as poison messages.</p><p>For an example, consider a stock ticker application that has been designed to consume prices |
| contained within JMS TextMessages. What if inadvertently a BytesMessage is placed onto the queue? |
| As the ticker application does not expect the BytesMessage, its processing might fail and cause it |
| to roll-back the transaction, however the default behavior of the Broker would mean that the |
| BytesMessage would be delivered over and over again, preventing the delivery of other legitimate |
| messages, until an operator intervenes and removes the erroneous message from the queue. </p><p>Qpid has maximum delivery count and dead-letter queue (DLQ) features which can be used in |
| concert to construct a system that automatically handles such a condition. These features are |
| described in the following sections.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Handling-Undeliverable-Messages-Maximum-Delivery-Count"></a>9.4.2. Maximum Delivery Count</h3></div></div></div><p> Maximum delivery count is an attribute of a queue. If a consumer application is unable to |
| process a message more than the specified number of times, then the Broker will either route the |
| message via the queue's <span class="emphasis"><em>alternate binding</em></span> (if one has been defined), or will |
| discard the message.</p><p>When using AMQP 1.0 the current delivery count of a message is available to the consuming |
| application via the<code class="literal">message-count</code> message header (exposed via the |
| <code class="literal">JMSXDeliveryCount</code> JMS message property when using JMS). When using the |
| AMQP 0-8..0-10 protocols this information is not available.</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> When using AMQP 0-8..0-10, in order for a maximum delivery count to be enforced, the consuming application |
| <span class="emphasis"><em>must</em></span> call <a class="link" href="http://docs.oracle.com/javaee/6/api/javax/jms/Session.html#rollback()" target="_top">Session#rollback()</a> (or <a class="link" href="http://docs.oracle.com/javaee/6/api/javax/jms/Session.html#recover()" target="_top">Session#recover()</a> if the session is not transacted). It is during the Broker's |
| processing of Session#rollback() (or Session#recover()) that if a message has been seen |
| at least the maximum number of times then it will move the message to the DLQ or discard the |
| message. If the consuming application fails in another manner, for instance, closes the connection, the |
| message will not be re-routed and consumer application will see the same poison message again |
| once it reconnects.</p><p> If the consuming application is using Qpid JMS Client 0-x and using AMQP 0-8, 0-9, or 0-9-1 |
| protocols, it is necessary to set the client system property <code class="varname">qpid.reject.behaviour</code> or |
| connection or binding URL option <code class="varname">rejectbehaviour</code> to the value <code class="literal">server</code>.</p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Java-Broker-Runtime-Handling-Undeliverable-Messages-Dead-Letter-Queues"></a>9.4.3. Alternate Binding</h3></div></div></div><p>Once the maximum delivery count is exceeded, if the queue has an <code class="literal">alternateBinding</code> |
| specified, the Broker automatically routes the message via the alternate binding. The alternate binding |
| would normally specify a queue designated for that purpose of receiving the undeliverable messages. |
| By convention such queues are known as dead-letter queues or simply DLQs.</p><div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Avoid excessive queue depth</h3><p>Applications making use of DLQs <span class="emphasis"><em>should</em></span> make provision for the frequent |
| examination of messages arriving on DLQs so that both corrective actions can be taken to resolve |
| the underlying cause and organise for their timely removal from the DLQ. Messages on DLQs |
| consume system resources in the same manner as messages on normal queues so excessive queue |
| depths should not be permitted to develop.</p></div></div></div><div class="navfooter"><hr /><table summary="Navigation footer" width="100%"><tr><td align="left" width="40%"><a accesskey="p" href="Java-Broker-Runtime-Transaction-Timeout.html">Prev</a> </td><td align="center" width="20%"><a accesskey="u" href="Java-Broker-Runtime.html">Up</a></td><td align="right" width="40%"> <a accesskey="n" href="Java-Broker-Runtime-Close-Connection-When-No-Route.html">Next</a></td></tr><tr><td align="left" valign="top" width="40%">9.3. Transaction Timeout </td><td align="center" width="20%"><a accesskey="h" href="Apache-Qpid-Broker-J-Book.html">Home</a></td><td align="right" valign="top" width="40%"> 9.5. Closing client connections on unroutable mandatory messages</td></tr></table></div></div> |
| |
| <hr/> |
| |
| <ul id="-apache-navigation"> |
| <li><a href="http://www.apache.org/">Apache</a></li> |
| <li><a href="http://www.apache.org/licenses/">License</a></li> |
| <li><a href="http://www.apache.org/foundation/sponsorship.html">Sponsorship</a></li> |
| <li><a href="http://www.apache.org/foundation/thanks.html">Thanks!</a></li> |
| <li><a href="/security.html">Security</a></li> |
| <li><a href="http://www.apache.org/"><img id="-apache-feather" width="48" height="14" src="" alt="Apache"/></a></li> |
| </ul> |
| |
| <p id="-legal"> |
| Apache Qpid, Messaging built on AMQP; Copyright © 2015 |
| The Apache Software Foundation; Licensed under |
| the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache |
| License, Version 2.0</a>; Apache Qpid, Qpid, Qpid Proton, |
| Proton, Apache, the Apache feather logo, and the Apache Qpid |
| project logo are trademarks of The Apache Software |
| Foundation; All other marks mentioned may be trademarks or |
| registered trademarks of their respective owners |
| </p> |
| </div> |
| </div> |
| </div> |
| </body> |
| </html> |
