On 1 April 2010 16:04, Shyam Santhanam <ssantha...@vmware.com> wrote:
> > There are a few more observations I've made while trying to debug this. > We've > noticed that sometimes the messages received from the consumer queues have > JMSDestination set to the VirtualTopic name, and at other times they have > the consumer queue name. As shown earlier, I do have the > excludedDestinations clause necessary to exclude forwarding to the queues. > Is this still to be expected? > > Hi shyam, we've seen this too - it depends on where the messages were sent to. Assume you have 2 brokers A and B. Connect your virtual topic consumer to A. Now if a message is sent to A, you get the topic name as destination. If a message is sent to B, you get the queue name as destination. > Also, looking in JMX at the VirtualTopic's topic MBeans, I've noticed that > the topics themselves have consumers in addition to the queue. Are these > consumers created internally by the broker to enable forwarding, or could > this indicate a problem? Further, there are far many more consumers for the > topics. For example, when testing with 2 nodes: Although I have only one > consumer queue attached to the topic, and one consumer to this topic on > each node, I notice that the VirtualTopic itself shows 6 consumers. Where > are these consumers coming from? > > Normally I see some extra consumers from the network of brokers. since we use suppressDuplicateQueueSubscriptions="true" on the network connectors I normally only see one additional consumer - what is your topology ? Another observation when looking at the MBeans: the QueueSize of the topics > appears to increase steadily over time. Could it be this : <https://issues.apache.org/activemq/browse/AMQ-2586> ? > When I try to browse the contents of > the topic, I often find that there are some residual messages (usually far > fewer messages than indicated by the QueueSize statistic, but > 0 > nonetheless). Again, this doesn't gel with my understanding. I thought that > the topics themselves are "virtual" which should imply that they don't have > a persistent cache of messages anywhere? Are the virtual topics themselves > also persisted? If so, when do messages in the topic get evacuated? > > You can use the topic as a normal topic - perhaps this is the effect you see ? when you subscribe then any messages received will be sent to your topic consumer. > If someone familiar with this area could answer these questions, it could > really help us make some important decisions about how, and whether, to use > virtual topics to implement our requirements. Has someone used them > effectively in a network-of-brokers scenario? If so, can you share the > specifics of your configuration? > > > Well we're in the middle of moving from durable consumer to virtual topics, so I wouldn't say we've got a final config yet. We're basically using the config as mentioned on the apache web pages. James. -- > View this message in context: > http://old.nabble.com/Problems-with-Virtual-Topics-tp28100311p28107798.html > Sent from the ActiveMQ - User mailing list archive at Nabble.com. > >
