Major Description
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:
"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
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:
public boolean contains(MessageReference message) { if (message != null) { for (PendingNode value : map.values()) { if (value.getMessage().equals(message)) { return true; } } } return false; }
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:
@Override public boolean contains(MessageReference message) { if (message != null) { return map.containsKey(message.getMessageId()); } return false; }
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.
