[ https://issues.apache.org/activemq/browse/AMQ-1020?page=comments#action_37340 ] james strachan commented on AMQ-1020: -------------------------------------
Are you using explicit acknowledgements or auto-ack (or transactions?). The default prefetch is only about 1000 I think for NMS which means after sending 1000 messages no more messages will be dispatched to a consumer until it receives acks. So I can see why Client1 becomes stuck pretty quickly and why client1 can no longer publish more messages. So 2 things to try... use dispatchAsync=true (on consumer info) on the consumers, so that dispatching to consumers is asynchronous in the broker. That way a producer won't get blocked waiting to dispatch to slow consumers. Also try upping the prefetch value to something large. e.g. on Java for non-persistent topics its about 32000 I think > Slow consumer terminally blocks both client and broker > ------------------------------------------------------ > > Key: AMQ-1020 > URL: https://issues.apache.org/activemq/browse/AMQ-1020 > Project: ActiveMQ > Issue Type: Bug > Components: Broker > Affects Versions: 4.0.2 > Environment: Broker: Windows XP, Sun JDK1.5 Client: activemq-dotnet > (Trunk) > Reporter: Rob Lugt > > I have a multi-threaded client (client1) which is acting as both a publisher > (Topic1) and subscriber (Topic2) using a single session. There is another > client process (client2) which publishes on Topic2. > I have witnessed the following repeatable scenario where both clients get > stuck, which can only be rectified by restarting the broker! :- > Client1 publishes messages to Topic1 (rate = about 30 msgs/sec). > Client2 publishes bursts of messages to Topic2 (rate = 500 msgs/sec) > Client1 is a slow subscriber on Topic2 > After running in this scenario for a couple of seconds, Client1 and Client2 > become stuck. Looking at a stack trace for Client1 I can see that it's > read_loop is stuck waiting for input, and it's publisher thread is stuck > waiting for an acknowledgement to the synchronous message send (the > acknowledgement never arrives because the broker won't sent any more > messages). > Client2 is also stuck waiting for an acknowledgement to a synchronous send. > My perception is that it appears the broker is throttling the connection > because the consumer is running slowly, but for some reason it gets into a > state where all message flow stops (even though the consumer is automatically > acknowledging messages, albeit slowly). Furthermore, if I kill Client1 the > broker doesn't recover (using a JMX console the connection remains visible). > The broker uses a vanilla configuration (i.e. no policies are set for the > topics in quedtion). > -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: https://issues.apache.org/activemq/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
