| <div class="docbook"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">9.9. Message Compression</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="Java-Broker-Runtime-Background-Recovery.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-Connection-Limit.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-Message-Compression"></a>9.9. Message Compression</h2></div></div></div><p>The Apache Qpid Broker-J supports<a class="footnote" href="#ftn.d0e6216" id="d0e6216"><sup class="footnote">[10]</sup></a> message compression. This feature works in co-operation with Qpid | |
| Clients implementing the same feature.</p><p>Once the feature is enabled (using Broker context variable | |
| <span class="emphasis"><em>broker.messageCompressionEnabled</em></span>), the Broker will advertise support for the | |
| message compression feature to the client at connection time. This allows clients to opt to turn | |
| on message compression, allowing message payload sizes to be reduced.</p><p>If the Broker has connections from clients who have message compression enabled and others who | |
| do not, it will internally, on-the-fly, decompress compressed messages when sending to clients | |
| without support and conversely, compress uncomressed messages when sending to clients who do.</p><p>The Broker has a threshold below which it will not consider compressing a message, this is | |
| controlled by Broker content variable | |
| (<code class="literal">connection.messageCompressionThresholdSize</code>) and expresses a size in bytes.</p><p>This feature <span class="emphasis"><em>may</em></span> have a beneficial effect on performance by:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>Reducing the number of bytes transmitted over the wire, both between Client and Broker, and | |
| in the HA case, Broker to Broker, for replication purposes.</p></li><li class="listitem"><p>Reducing storage space when data is at rest within the Broker, both on disk and in | |
| memory.</p></li></ul></div><p>Of course, compression and decompression is computationally expensive. Turning on the feature | |
| may have a negative impact on CPU utilization on Broker and/or Client. Also for small messages | |
| payloads, message compression may increase the message size. It is recommended to test the feature | |
| with representative data.</p><div class="footnotes"><br /><hr style="width:100; text-align:left;margin-left: 0" /><div class="footnote" id="ftn.d0e6216"><p><a class="para" href="#d0e6216"><sup class="para">[10] </sup></a>Message compression is not yet supported for the 1.0 | |
| protocol.</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-Background-Recovery.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-Connection-Limit.html">Next</a></td></tr><tr><td align="left" valign="top" width="40%">9.8. Background Recovery </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%"> 9.10. Connection Limits</td></tr></table></div></div> |