Message group not working when first group has large number of messages
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We are evaluating usage of message groups on ActiveMQ 5.5.1 using JDBC based Master/Slave configuration, with 1 queue and 8 consumers, prefetch = 1. What we are seeing is that if the queue is flooded with messages (we tried in the range of 20K) belonging to one group in short time-span and then add messages belonging to different groups, the messages belonging to different groups get processed serially by the same consumer instead of going to different consumer. We are using simpleMessageGroupMapFactory policy as our Message group Ids can have any long number.
Re: Message group not working when first group has large number of messages
Going by the older discussion around similar problem faced in case of message selectors, it seems that maxPageSize is the one causing this effect i.e. the messages from fetched page are getting considered for group assignment and consumer load balancing .... I increased this limit to > 20k and now see that messages on queue behind 20k messages from one group do get processed by a different consumer ......