Hi Amila, Yes it shouldn't be a problem. The only concern is that we need to define a time interval which is less than the time it takes to restart the message broker. Otherwise the health check won't notice the unavailability of the message broker and as a result message subscribers will not get re-connected. Consequently messages won't get received thereafter.
Thanks On Wed, Aug 6, 2014 at 1:54 AM, Amila Maha Arachchi <[email protected]> wrote: > Re-igniting this thread: > > Yes, this message is discarded since there are no subscribers to the > topic. So, it does not seems harmful. > > Yet, since WSO2 MB uses Apache Cassandra, this seems to cause problems > when keep running for few days. Because of that, we are considering about > reducing the frequency of this ping message. > > Imesh, > > What are the cons of reducing the frequency to 5 seconds or so (default > seems to be one second) to send the ping message? I believe it is the delay > to detect any connection drop? Can this end up in a message loss? I think > it won't because the mms client should retry. Isn't it? > > Regards, > Amila. > > > On Wed, May 21, 2014 at 2:43 PM, Udara Liyanage <[email protected]> wrote: > >> Hi, >> >> MESSAGE DISCARDED: No routes for message - Messag.. >> >> I see above log in the logs Amila has pasted. The messages >> are discarded since there is no subscriber ? Unless the topic is a durable >> topic the messages are discarded when there are no subscriber I guess. >> >> >> >> On Mon, May 19, 2014 at 6:43 PM, Nirmal Fernando <[email protected]> >> wrote: >> >>> We have to stop persisting and set a expiration time may be. Is the time >>> interval of this topic is configurable? >>> >>> >>> On Mon, May 19, 2014 at 1:40 PM, Udara Liyanage <[email protected]> wrote: >>> >>>> Hi, >>>> >>>> Is there any way that we can specify to discard the messages after >>>> sometime if they are not consumed? If so we can let the ping messages to >>>> automatically discard after sometime. >>>> >>>> >>>> On Mon, May 12, 2014 at 9:46 PM, Imesh Gunaratne <[email protected]> >>>> wrote: >>>> >>>>> Thanks Amila for bringing this up. The idea of this implementation was >>>>> to introduce a generic implementation for any AMQP based message broker to >>>>> detect a connection drop and re-connect. The problem was with the message >>>>> subscribers. Yes we need to have a message consumer for the ping topic to >>>>> avoid the message broker being overloaded. >>>>> >>>>> I started a discussion on this topic here [1] with respective to >>>>> ActiveMQ. It seems like ActiveMQ provides a solution for this problem. The >>>>> concern we have here is that whether this is something the message broker >>>>> should handle. If so we could simply ignore this functionality in Stratos. >>>>> >>>>> [1] >>>>> http://stackoverflow.com/questions/23503720/how-to-detect-a-connection-drop-in-an-activemq-subscriber >>>>> >>>>> Thanks >>>>> >>>>> >>>>> On Sun, May 11, 2014 at 10:37 PM, Udara Liyanage <[email protected]> >>>>> wrote: >>>>> >>>>>> Hi, >>>>>> >>>>>> Yes it might cause problems in long run. Some cleanup process to >>>>>> subscribe to the ping topic and discard might be useful. >>>>>> >>>>>> >>>>>> >>>>>> Touched, not typed. Erroneous words are a feature, not a typo. >>>>>> On May 11, 2014 8:55 AM, "Amila Maha Arachchi" <[email protected]> >>>>>> wrote: >>>>>> >>>>>>> Hi Devs, >>>>>>> >>>>>>> I am working with a Stratos deployment these days. In our >>>>>>> deployment, we are using WSO2 Message Broker as the message broker. >>>>>>> There I >>>>>>> see the following log getting printed very frequently (every second). >>>>>>> >>>>>>> TID: [0] [MB] [2014-05-05 08:31:52,352] INFO >>>>>>> {org.wso2.andes.server.exchange.TopicExchange} - Message routing key: >>>>>>> ping >>>>>>> No routes. {org.wso2.andes.server.exchange.TopicExchange} >>>>>>> >>>>>>> TID: [0] [MB] [2014-05-05 08:31:52,352] WARN >>>>>>> {org.wso2.andes.server.AMQChannel} - MESSAGE DISCARDED: No routes for >>>>>>> message - Message[(HC:449176483 ID:366318838955900928 Ref:0)]: >>>>>>> 366318838955900928; ref count: 0 {org.wso2.andes.server.AMQChannel} >>>>>>> >>>>>>> TID: [0] [MB] [2014-05-05 08:31:52,621] INFO >>>>>>> {org.wso2.andes.server.exchange.TopicExchange} - Message routing key: >>>>>>> ping >>>>>>> No routes. {org.wso2.andes.server.exchange.TopicExchange} >>>>>>> >>>>>>> TID: [0] [MB] [2014-05-05 08:31:52,621] WARN >>>>>>> {org.wso2.andes.server.AMQChannel} - MESSAGE DISCARDED: No routes for >>>>>>> message - Message[(HC:1522105342 ID:366318839026417664 Ref:0)]: >>>>>>> 366318839026417664; ref count: 0 {org.wso2.andes.server.AMQChannel} >>>>>>> >>>>>>> I came to know that this is due to a mechanism used to check whether >>>>>>> the Message Broker (MB) is alive. i.e. subscribers publish an event to >>>>>>> this >>>>>>> "ping" topic to see whether the MB is alive, but no one is consuming it. >>>>>>> Thats why the above log is getting printed. >>>>>>> >>>>>>> Since no one is consuming this messages, is it possible that MB gets >>>>>>> loaded with this message and cause problems? >>>>>>> >>>>>>> Regards, >>>>>>> Amila. >>>>>>> >>>>>>> -- >>>>>>> *Amila Maharachchi* >>>>>>> Senior Technical Lead >>>>>>> WSO2, Inc.; http://wso2.com >>>>>>> >>>>>>> Blog: http://maharachchi.blogspot.com >>>>>>> Mobile: +94719371446 >>>>>>> >>>>>>> >>>>> >>>>> >>>>> -- >>>>> Imesh Gunaratne >>>>> >>>>> Technical Lead, WSO2 >>>>> Committer & PPMC Member, Apache Stratos >>>>> >>>> >>>> >>>> >>>> -- >>>> >>>> Udara Liyanage >>>> Software Engineer >>>> WSO2, Inc.: http://wso2.com >>>> lean. enterprise. middleware >>>> >>>> web: http://udaraliyanage.wordpress.com >>>> phone: +94 71 443 6897 >>>> >>> >>> >>> >>> -- >>> Best Regards, >>> Nirmal >>> >>> Nirmal Fernando. >>> PPMC Member & Committer of Apache Stratos, >>> Senior Software Engineer, WSO2 Inc. >>> >>> Blog: http://nirmalfdo.blogspot.com/ >>> >> >> >> >> -- >> >> Udara Liyanage >> Software Engineer >> WSO2, Inc.: http://wso2.com >> lean. enterprise. middleware >> >> web: http://udaraliyanage.wordpress.com >> phone: +94 71 443 6897 >> > > > > -- > *Amila Maharachchi* > Senior Technical Lead > WSO2, Inc.; http://wso2.com > > Blog: http://maharachchi.blogspot.com > Mobile: +94719371446 > > -- Imesh Gunaratne Technical Lead, WSO2 Committer & PPMC Member, Apache Stratos
