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Extracting jbosscache async listener stats
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modified by <a href="http://community.jboss.org/people/cullendw">Daniel Cullender</a> in <i>JBoss Cache Development</i> - <a href="http://community.jboss.org/docs/DOC-14766">View the full document</a>
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<div class="jive-rendered-content"><p>We are currently using jbosscache core 3.2.1.GA and currently push literally millions of records into it. We have asynchronous listeners processing the data as it is put into the cache.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>The problem is that the listeners cannot process the data quickly enough and this causes a backlog in the async queue size (which is set to a number in the millions). Increasing the Async pool size over 250 does not help either based on the various (but necessary) locks we have in place.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>In order to successfully manage the backlog, we needed to monitor the cache's Async Listener's Queue size to see when it grows too large. Unfortunately, we could not find a way to access these type of stats from the cache, so we downloaded the source code and exposed these stats ourselves.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p><strong>Code Modifications</strong></p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><ol><li>We created a new immutable VO called org.jboss.cache.notifications.NotifierRuntime which holds the various statistics relating to the async listener queue and pool</li><li>In the org.jboss.cache.notifications.NotifierImpl class, keep a reference to the ThreadPoolExecutor which the BoundedExecutor assigns to the AsyncProcessor since this contains all the information you need to extract the queue size (along with other useful stats)</li><li>Expose a method on the org.jboss.cache.notifications.Notifier interface and the org.jboss.cache.Cache interface to expose a method which returns this immutable object (org.jboss.cache.notifications.NotifierRuntime) which is populated with delicious data (Our object contains minimal info, but could easily be extended to expose a whole lot more data).</li></ol><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>These statistics have helped us manage the backlog and keep our application afloat.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>To access these stats, all you need to do is invoke the getNotifierRuntime() on the org.jboss.cache.Cache interface.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>I have attached the source code for anyone who has a similar requirement.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p><strong>Update</strong></p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>I have updated the jbosscache-core source code for for 3.2.5.AG (please find the jar attached). I replicated the steps mentioned above and no additional steps were required.</p></div>
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