Hi Vadim, On 7/31/06, Vadim Pesochinsky <[EMAIL PROTECTED]> wrote:
Hi! I have a test case to consider. 2 servers are processing 3 submitted jobs with following processing times 10 min, 1 min, 1 min. This sequence should finish in 10 minutes as one service will pick up the 10 minutes job, meanwhile the other one should manage the two 1 minute jobs. Since I cannot set prefetchSize=0, one of the 1 minute jobs is sitting in prefetch buffer and the jobs are processed in 11 minutes instead of 10.
I would think that a 10 min job will sit in the prefetch buffer in 1 consumer and a 1 min job sit in the prefetch buffer of the 2nd consumer and the last 1 min job will not be in any prefetch buffer. It will be waiting for one of the 2 consumers prefetch buffers to empty. Since the prefetch buffer usage is only decreased when the message is acknowledged, if you acknowledge the message after you have processed it, I think it should work how you want it to work. If you are using AUTO-ACK, the message gets acked as soon as the message is received() before you process it. So then another message queues up waiting for your 10 min processing time. I think if you witch to using client ack or to using transacted sessions, things should work better for you.
This is simplification of the real scenario where I have about 30 consumers submitting jobs to 20 consumers through AMQ 4.0.1. I have following problems: • Messages are sitting in prefetch buffer are not available to processors, which results in a lot of idle time. • Order of processing is random. For some reason Job # 20 is processed after Job # 1500. Since senders are synchronously blocked this can result in time-outs. What can I do to work around these problems? Any configuration changes? How to set prefetchSize=0; should submit a JIRA for this? Environment & Configuration AMQ 4.0.1 QUEUE_NAME?consumer.prefetchSize=1;consumer.dispatchAsync=true <beans xmlns="http://activemq.org/config/1.0";> <!-- Allows us to use system properties as variables in this configuration file --> <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"/> <broker useJmx="true" deleteAllMessagesOnStartup="true" persistent="true" > <!-- Use the following to configure how ActiveMQ is exposed in JMX --> <managementContext> <managementContext connectorPort="1099" jmxDomainName="org.apache.activemq"/> </managementContext> <destinationPolicy> <policyMap> <policyEntries> <policyEntry topic="FIN.>"> <dispatchPolicy> <strictOrderDispatchPolicy /> </dispatchPolicy> <pendingMessageLimitStrategy> <constantPendingMessageLimitStrategy limit="0"/> </pendingMessageLimitStrategy> <messageEvictionStrategy> <oldestMessageEvictionStrategy /> </messageEvictionStrategy> </policyEntry> </policyEntries> </policyMap> </destinationPolicy> <persistenceAdapter> <kahaPersistentAdaptor dir="activemq-kaha"/> </persistenceAdapter> <transportConnectors> <transportConnector name="default" uri="tcp://localhost:61616" discoveryUri="multicast://default"/> </transportConnectors> <networkConnectors> <networkConnector name="default" uri="static://(tcp://localhost:61616)"/> </networkConnectors> </broker> </beans> -- View this message in context: http://www.nabble.com/Trouble-with-prefetch-buffer.-tf2029800.html#a5583273 Sent from the ActiveMQ - User forum at Nabble.com.
-- Regards, Hiram Blog: http://hiramchirino.com
