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https://issues.apache.org/jira/browse/APLO-206?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hiram Chirino updated APLO-206:
-------------------------------
Component/s: (was: apollo-cli)
(was: apollo-bdb)
apollo-stomp
apollo-openwire
> Load balance of job queues
> --------------------------
>
> Key: APLO-206
> URL: https://issues.apache.org/jira/browse/APLO-206
> Project: ActiveMQ Apollo
> Issue Type: Improvement
> Components: apollo-broker, apollo-openwire, apollo-stomp
> Affects Versions: 1.3
> Reporter: José Micó
> Fix For: 1.4
>
>
> I wish to have load balanced job queues, like in ActiveMQ (copied and pasted):
> "A queue implements load balancer semantics. A single message will be
> received by exactly one consumer. If there are no consumers available at the
> time the message is sent it will be kept until a consumer is available that
> can process the message. If a consumer receives a message and does not
> acknowledge it before closing then the message will be redelivered to another
> consumer. A queue can have many consumers with messages load balanced across
> the available consumers."
> For example, suppose that I send tree jobs (j1, j2, j3) to a queue with 2
> consumers (c1,c2).
> The first job takes 10 seconds to complete, jobs 2 and 3 takes only 1 second.
> Consumers are using 'client' ack, with credit:1,0 in order to receive only
> one job at the time.
> The desired behaviour of consumers is:
> [ 21:30:00 ][ c1 ] Got job 1
> [ 21:30:00 ][ c2 ] Got job 2
> [ 21:30:01 ][ c2 ] Ack job 2, now idle
> [ 21:30:01 ][ c2 ] Got job 3
> [ 21:30:02 ][ c2 ] Ack job 3, now idle
> [ 21:30:10 ][ c1 ] Ack job 1, now idle
> But currently, Apollo does:
> [ 21:30:00 ][ c1 ] Got job 1
> [ 21:30:00 ][ c2 ] Got job 2
> [ 21:30:01 ][ c2 ] Ack job 2, now idle (!) c2 is idle but does not gets job
> 3
> [ 21:30:10 ][ c1 ] Ack job 1, now idle
> [ 21:30:10 ][ c1 ] Got job 3
> [ 21:30:11 ][ c1 ] Ack job 3, now idle
> Seems that jobs are assigned in a round-robin fashion at the moment of being
> received by the broker.
> If in this example I send 9 jobs of 1 second (instead of 2), consumer #1 gets
> 5 and consumer #2 gets the remaining 5, when the optimum would be to send the
> 9 fast jobs to consumer #2 while consumer #1 is processing the slow one. I
> know that using 'client' ack with credit:1,0 is suboptimal from broker
> perspective, but is the optimal way to balance jobs between workers.
> Besides the underutilization of resources, the main problem is that if a
> consumer takes too much time to process a job (say, due to a DB lock) it may
> block the processing of a bunch of jobs already assigned to it.
> ...
> BTW, impressive piece of work!!! I really impressed by the completeness of
> features, and how well Apollo behaved when I overloaded it with stress tests
> :)
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