Hi Gary, Thanks for the feedback. As you can see from my stack traces earlier in jconsole, the consumers are stuck on pulling messages from the queues, they are in: org.apache.activemq.MessageDispatchChannel.dequeue
The reason I've ended up with the settings I have as so far they seem to be give me the desired results (apart from this last problem). Maybe it would be easier to explain the behaviur I need and someone might be able to advise on the best settings... So most messages sent are persistent, and I need to process every message - I can't afford to drop any. I may have slow "consumers", and I might be putting messages on to the queues at a far greater rate than they can get processed (I want any available harddisk space to be used for message storage). There are a a number of consumers and producers, and a number of different queues. The pre-fetch size was set to zero to overcome an issue I was having with redelivery count. Our application uses the JMS redelivered to see if it has already tried processing the message. Using a pre-fetch size bigger than 0 was causing me some issues with this. Out of interest, do you know what happens to messages that are pre-fetched and then the consumer dies. Do they get flagged as redelivered when a new consumer picks them up? Gary Tully wrote: > > A good place to start is with JCosole, to have a look at the queues > and consumers to see how many messages are currently in the queues. > >>The broker is configured with producerFlowControl="false", using TCP, a >>pre-fetch size of 0 and I've also set sendFailIfNoSpace="true". >> > The sendFailIfNoSpace is disabled if producerFlowControl==false, so > your producers will hang if memory for the queues are exhausted. > sendFailIfNoSpace is considered a flowControl mechanism that does not > block so it needs producerFlowControl to be enabled (the default) and > no producer window to be set (also the default). > > Just a thought, but is it possible that the consumers are blocking > when trying to "stick messages" back on a queue? > > Out of interest, why are you using prefetch==0? > > 2009/1/13 IBeaumont <ibeaum...@categoric.com>: >> >> I've got a fairly complex app, that takes msgs, processing them and >> sticks >> them on the same or different queues. >> >> The queues are pre-loaded with persistent messages before the application >> starts (50000). Once it starts processing things work fine for a while >> and >> then the consumers stop receiving any messages. I have a 4 consumers for >> each queue, and there are 3 different queues. >> >> Looking at jconsole all consumes are waiting here: >> >> State: WAITING on java.lang.obj...@1801d4a >> Total blocked: 20 Total waited: 158 >> >> Stack trace: >> java.lang.Object.wait(Native Method) >> java.lang.Object.wait(Object.java:485) >> org.apache.activemq.MessageDispatchChannel.dequeue(MessageDispatchChannel.java:75) >> org.apache.activemq.ActiveMQMessageConsumer.dequeue(ActiveMQMessageConsumer.java:412) >> org.apache.activemq.ActiveMQMessageConsumer.receiveNoWait(ActiveMQMessageConsumer.java:560) >> com.xalert.server.queuing.SessionManager.getAlert(SessionManager.java:236) >> >> >> If I look at the broker (and I'm not really sure what to look at here), >> the >> thread for my queue that should be dispatching messages looks like this >> Name: QueueThread:queue://csPIQ >> State: WAITING on >> java.util.concurrent.locks.abstractqueuedsynchronizer$conditionobj...@b0a518 >> Total blocked: 2,365 Total waited: 6,717 >> >> Stack trace: >> sun.misc.Unsafe.park(Native Method) >> java.util.concurrent.locks.LockSupport.park(Unknown Source) >> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(Unknown >> Source) >> java.util.concurrent.LinkedBlockingQueue.take(Unknown Source) >> java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source) >> java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) >> java.lang.Thread.run(Unknown Source) >> >> The broker is configured with producerFlowControl="false", using TCP, a >> pre-fetch size of 0 and I've also set sendFailIfNoSpace="true". >> >> Any ideas on what my problem is or how/where I look in ActiveMQ to find >> the >> cause, or if the problem is with the consumer. >> >> TIA >> Ian >> >> -- >> View this message in context: >> http://www.nabble.com/Q-Consumers-stop-receiving-messages-tp21438163p21438163.html >> Sent from the ActiveMQ - User mailing list archive at Nabble.com. >> >> > > > > -- > http://blog.garytully.com > > Open Source SOA > http://FUSESource.com > > -- View this message in context: http://www.nabble.com/Q-Consumers-stop-receiving-messages-tp21438163p21440240.html Sent from the ActiveMQ - User mailing list archive at Nabble.com.
