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Date: Fri, 30 Jan 2015 07:07:24 -0800 (PST)
From: artnaseef <art@artnaseef.com>
To: users@activemq.apache.org
Message-ID: <1422630444808-4690727.post@n4.nabble.com>
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 <CAPVVMa8GVikGUhFjAOrAyG5fhknTuhbMGgkzzdr-GSUGRBfu-g@mail.gmail.com>
Subject: Re: Message priority and message selector - Active MQ version 5.4
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tbain98 has the right idea.  And that raises an interesting question
regarding messages on-disk and not in-memory - I need to review to see how
that operates.

Here's how I expect it to work: the consumer with it's exclusive selector
will get all pending messages which match its selector regardless of what
other messages are unconsumed on the Queue.

It would be easy to test the disk case too, like this:
* Start a broker with persistence enabled (e.g. KahaDB)
* Do not start any consumers
* Produce a large number of persistent messages to a queue; split 50/50
between two selectors (10k or 100k should be adequate)
* Shutdown the broker
* Start the broker back up
* Consume with only one selector and confirm it receives all of the matching
messages.

Now I'm curious and want to review the code.

Note this scenario is another one I'll put on my list of reasons that
selectors are bad for performance.  If the broker has to replay every
message in storage to possibly find those that match a single selector every
time a new consumer is added, that could lead to some terrible performance
scenarios.

To the original use-case, can separate queues be used instead?


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