For the past 2 weeks we have been testing ActiveMQ to answer this question ourself. Here is what we found.
Creating a Connection takes one thread. Creating a Session takes one thread. Creating a NON Persisted Topic with a messageListner takes one thread, when the topic is no longer used the thread is returned to the system. Creating a Persisted Topic with a messageListner takes one thread this thread seems to stay around even when the Producer is disposed. Creating a QUEUE creates 1 thread per QUEUE when the QUEUE is disposed the thread servicing the QUEUE is still in use. On Windows 32 Bit we were able to get up to 2,000 threads before we could not create anymore. On Linux 32 Bit we were able to get up to about 2,500 threads before we could not create anymore. It is important to note that I had to make ulimit changes to memory size, virtual memory size and file handles in order to reach more then 1,000. On Windows 64 Bit with a 64 bit JVM we were able to get up to 5,000 threads before we could not create anymore. On Linux 64 Bit with a 64bit JVM we were able to get up to about 6,000 threads before we could not create anymore. It is important to note that I had to make ulimit changes to memory size, virtual memory size and file handles in order to reach more. Ken Ringdahl wrote: > > I'm running a load test that intends to throw on the order of several > thousand connections at a 2 node broker system with failover (ActiveMQ > 4.1.1) configured for tcp transport only. However, I'm just using a > single broker node right now and am getting out of memory errors at about > 400 connections. I've set the Xmx to 1024M and the memory is only ~110 MB > when this error occurs in the log. I've pasted the exceptions below. > The latter 2 exceptions do not immediately follow the first. They come > maybe a minute or so later. I've tried setting the preFetch to 1 in case > it's keeping messages in memory. But, to be honest, my test doesn't send > messages until all of the connections have been established. Any > suggestions as to what might be the problem here? > > > > jvm 1 | Exception in thread "ActiveMQ Transport Server: > tcp://localhost:61616" java.lang.OutOfMemoryError: unable to create new > native thread > jvm 1 | at java.lang.Thread.start0(Native Method) > jvm 1 | at java.lang.Thread.start(Thread.java:574) > jvm 1 | at > org.apache.activemq.thread.DedicatedTaskRunner.<init>(DedicatedTaskRunner.java:45) > jvm 1 | at > org.apache.activemq.thread.TaskRunnerFactory.createTaskRunner(TaskRunnerFactory.java:77) > jvm 1 | at > org.apache.activemq.broker.TransportConnection.<init>(TransportConnection.java:174) > jvm 1 | at > org.apache.activemq.broker.jmx.ManagedTransportConnection.<init>(ManagedTransportConnection.java:55) > jvm 1 | at > org.apache.activemq.broker.jmx.ManagedTransportConnector.createConnection(ManagedTransportConnector.java:56) > jvm 1 | at > org.apache.activemq.broker.TransportConnector$1.onAccept(TransportConnector.java:147) > jvm 1 | at > org.apache.activemq.transport.tcp.TcpTransportServer.run(TcpTransportServer.java:167) > jvm 1 | at java.lang.Thread.run(Thread.java:595) > jvm 1 | Exception in thread "RMI RenewClean-[172.16.105.110:36883]" > java.lang.OutOfMemoryError: unable to create new native thread > jvm 1 | at java.lang.Thread.start0(Native Method) > jvm 1 | at java.lang.Thread.start(Thread.java:574) > jvm 1 | at > sun.rmi.transport.tcp.TCPChannel.free(TCPChannel.java:321) > jvm 1 | at sun.rmi.server.UnicastRef.free(UnicastRef.java:395) > jvm 1 | at sun.rmi.server.UnicastRef.done(UnicastRef.java:412) > jvm 1 | at sun.rmi.transport.DGCImpl_Stub.dirty(Unknown Source) > jvm 1 | at > sun.rmi.transport.DGCClient$EndpointEntry.makeDirtyCall(DGCClient.java:328) > jvm 1 | at > sun.rmi.transport.DGCClient$EndpointEntry.access$1600(DGCClient.java:144) > jvm 1 | at > sun.rmi.transport.DGCClient$EndpointEntry$RenewCleanThread.run(DGCClient.java:539) > jvm 1 | at java.lang.Thread.run(Thread.java:595) > jvm 1 | Exception in thread "ActiveMQ Journal Checkpoint Worker" > java.lang.OutOfMemoryError: unable to create new native thread > jvm 1 | at java.lang.Thread.start0(Native Method) > jvm 1 | at java.lang.Thread.start(Thread.java:574) > jvm 1 | at > edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor.addIfUnderCorePoolSize(ThreadPoolExecutor.java:429) > jvm 1 | at > edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:857) > jvm 1 | at > org.apache.activemq.store.journal.JournalPersistenceAdapter.doCheckpoint(JournalPersistenceAdapter.java:376) > jvm 1 | at > org.apache.activemq.store.journal.JournalPersistenceAdapter$2.iterate(JournalPersistenceAdapter.java:129) > jvm 1 | at > org.apache.activemq.thread.DedicatedTaskRunner.runTask(DedicatedTaskRunner.java:101) > jvm 1 | at > org.apache.activemq.thread.DedicatedTaskRunner.access$000(DedicatedTaskRunner.java:25) > jvm 1 | at > org.apache.activemq.thread.DedicatedTaskRunner$1.run(DedicatedTaskRunner.java:39) > > -- View this message in context: http://www.nabble.com/ActiveMQ-Transport-Server-OutOfMemoryError-while-running-load-test-tf4697790s2354.html#a13733932 Sent from the ActiveMQ - User mailing list archive at Nabble.com.
