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https://issues.apache.org/jira/browse/AMQ-6066?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Christopher L. Shannon updated AMQ-6066:
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Fix Version/s: 5.12.2
> Performance issue in OrderedPendingList
> ---------------------------------------
>
> Key: AMQ-6066
> URL: https://issues.apache.org/jira/browse/AMQ-6066
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.12.1
> Reporter: David Sitsky
> Assignee: Christopher L. Shannon
> Fix For: 5.13.0, 5.12.2
>
>
> I have updated my application from ActiveMQ 5.3 to 5.11.1 and have noticed a
> serious performance degregation. Running a number of jstacks I can see the
> broker is often stuck here:
> {noformat}
> "Queue:master-items" Id=122 RUNNABLE
> at
> org.apache.activemq.broker.region.cursors.OrderedPendingList.contains(OrderedPendingList.java:144)
> at
> org.apache.activemq.broker.region.Queue.doPageInForDispatch(Queue.java:1930)
> at
> org.apache.activemq.broker.region.Queue.pageInMessages(Queue.java:2119)
> at org.apache.activemq.broker.region.Queue.iterate(Queue.java:1596)
> - locked java.lang.Object@253c3089
> at
> org.apache.activemq.thread.DedicatedTaskRunner.runTask(DedicatedTaskRunner.java:112)
> at
> org.apache.activemq.thread.DedicatedTaskRunner$1.run(DedicatedTaskRunner.java:42)
> Number of locked synchronizers = 1
> - java.util.concurrent.locks.ReentrantReadWriteLock$NonfairSync@2eb46567
> {noformat}
> For this specific queue in my application, there were a large number of items
> in it.. around 100,000. However I noticed the code for contains has:
> {code}
> public boolean contains(MessageReference message) {
> if (message != null) {
> for (PendingNode value : map.values()) {
> if (value.getMessage().equals(message)) {
> return true;
> }
> }
> }
> return false;
> }
> {code}
> This will obviously be very slow. Given the Map is keyed by message ID,
> can't we do a .contains(message.getMessageId()) instead? I noticed the
> remove() method does this. I changed the code to do this:
> {code}
> @Override
> public boolean contains(MessageReference message) {
> if (message != null) {
> return map.containsKey(message.getMessageId());
> }
> return false;
> }
> {code}
> I got a speedup for my test which now takes 29 minutes from 41 minutes. Can
> we get this change in to the upcoming 5.13 release (pretty please??) It is a
> tiny (but very important) change for us.. many thanks.
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