| <div class="docbook"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">9.8. Background Recovery</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="Java-Broker-Runtime-Consumers.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-Message-Compression.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-Background-Recovery"></a>9.8. Background Recovery</h2></div></div></div><p>On startup of the Broker, or restart of a Virtualhost, the Broker restores all durable | |
| queues and their messages from disk. In the Broker's default mode the Virtualhosts do not become | |
| active until this recovery process completes. If queues have a large number of entries, this may | |
| take considerable time. During this time no messaging can be performed.</p><p>The Broker has a background recovery feature allows the system to return to operation | |
| sooner. If enabled the recovery process takes place in the background allow producers and | |
| consumers to begin work earlier.</p><p>The feature respects the message delivery order requirements of standard queues, that is any | |
| messages arriving whilst the background recovery is in flight won't overtake older messages | |
| still to be recovered from disk. There is an exception for the out of order queue types whilst | |
| background recovery is in flight. For instance, with priority queues older lower priority | |
| messages may be delivered before newer, higher priority.</p><p>To activate the feature, set a <a class="link" href="Java-Broker-Management-Managing-Entities.html#Java-Broker-Management-Managing-Entities-General" title="7.1. General Description">context variable</a> | |
| <code class="literal">use_async_message_store_recovery</code> at the desired Virtualhost, or at Broker or | |
| higher to enable the feature broker-wide.</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>The background recovery feature does not write operational log messages to indicate its | |
| progress. This means messages <a class="link" href="Java-Broker-Appendix-Operation-Logging.html#Java-Broker-Appendix-Operation-Logging-Message-MST-1004">MST-1004</a> and <a class="link" href="Java-Broker-Appendix-Operation-Logging.html#Java-Broker-Appendix-Operation-Logging-Message-MST-1005">MST-1005</a> will not | |
| be seen.</p></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-Consumers.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-Message-Compression.html">Next</a></td></tr><tr><td align="left" valign="top" width="40%">9.7. Consumers </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%"> 9.9. Message Compression</td></tr></table></div></div> |