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From "James Strachan" <james.strac...@gmail.com>
Subject Re: handling slow consumers on non-persistent topics and AMQ-688
Date Tue, 04 Jul 2006 06:37:59 GMT
Are you totally convinced it requires a new branch; e.g. what if we
created a whole new Region implementation in another package or
something?

On 7/4/06, Hiram Chirino <hiram@hiramchirino.com> wrote:
> I think that fixing these issues are going to require substancial work on
> internals of the broker.  I want to try to take a stab fixing this stuff but
> since it's going to take a few iterations to get right, how about we branch
> trunk and work there to avoid breaking everbody else?  Any sugestions for
> the branch name?
>
> Regards,
> Hiram
>
> On 7/3/06, James Strachan <james.strachan@gmail.com> wrote:
> >
> > While perusing JIRA I spotted this issue again...
> > http://issues.apache.org/activemq/browse/AMQ-688
> > I know its an issue close to folks at Amazon's hearts.
> >
> > Dealing with slow consumers is a fascinating problem for a messaging
> > system; its quite a tricky problem :). Here's some background on the
> > issue...
> > http://incubator.apache.org/activemq/slow-consumers.html
> >
> > together with the currently supported features - to allow messages to
> > be discarded on slow consumers using a pluggable algorithm...
> > http://incubator.apache.org/activemq/slow-consumer-handling.html
> >
> > Now for all consumers we fill up prefetch buffers as quickly as
> > possible...
> > http://incubator.apache.org/activemq/what-is-the-prefetch-limit-for.html
> >
> > so there's always a buffer of messages per consumer. For non-durable
> > topics once these messages are written to a socket they are evicted
> > from RAM; so we already have some support for slow consumers.
> >
> > I wanted to start a discussion on both AMQ-688 and to see if folks had
> > other requirements for handling slow consumers & to try decide what
> > features & stragegies we should add next in this area.
> >
> > One of the first requirements folks ask for is that rather than
> > blocking permanently the non-persistent topic engine until RAM is
> > cleared, that at a certain threshhold we start spooling to disk. I've
> > raised a separate JIRA issue for this specific feature request...
> >
> > http://issues.apache.org/activemq/browse/AMQ-791
> >
> > Another issue some folks have hit in the past is that for high
> > performance and to minimise context switches in the broker, we tend to
> > use the current thread in the broker to dispatch to all the
> > non-durable topic consumers so a slow/blocked consumer can appear to
> > 'block' the producer.
> >
> > I've raised this issue to track that feature
> > http://issues.apache.org/activemq/browse/AMQ-792
> >
> > I just wondered if folks had any other issues or requirements with the
> > whole slow consumers and non-durable topics they'd like to discuss? Is
> > there any requirements we won't have covered if the above two JIRAs
> > are fixed
> > --
> >
> > James
> > -------
> > http://radio.weblogs.com/0112098/
> >
>
>
>
> --
> Regards,
> Hiram
>
> Blog: http://hiramchirino.com
>
>


-- 

James
-------
http://radio.weblogs.com/0112098/

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