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From: Paul Gale <paul.n.gale@gmail.com>
Date: Fri, 28 Jun 2013 09:52:03 -0400
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Subject: Re: kahadb system property configuration options
To: users@activemq.apache.org
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Thanks for the feedback!


On Fri, Jun 28, 2013 at 8:27 AM, Gary Tully <gary.tully@gmail.com> wrote:

> It was an effort to increase the write throughput, but for kahadb the
> bottleneck is the index so any gain/loss for different workloads was
> over shadowed.
> For the moment, stick with the defaults. The logging may help identify
> the best value for journalMaxWriteBatchSize.
>
> On 27 June 2013 18:55, Christian Posta <christian.posta@gmail.com> wrote:
> > Maybe Gary can give you more info, but the caller buffer appender is an
> > experimental appender to help offload the buffering of writes to calling
> > threads and reduce the time spent in the thread that actually writes to
> the
> > journal. The write stat window is for logging purposes to get an idea of
> an
> > avg size of write batches per WRITE_STAT_WINDOW writes.
> >
> >
> >
> >
> > On Thu, Jun 27, 2013 at 9:27 AM, Paul Gale <paul.n.gale@gmail.com>
> wrote:
> >
> >> Hi,
> >>
> >> I came across the following system properties that are uses by the
> >> kahaDBPersistenceAdapter, their default values are:
> >>
> >> -Dorg.apache.kahadb.journal.appender.WRITE_STAT_WINDOW=0
> >> -Dorg.apache.kahadb.journal.CALLER_BUFFER_APPENDER=false
> >>
> >> A particular unit test recommends setting them to:
> >>
> >> -Dorg.apache.kahadb.journal.appender.WRITE_STAT_WINDOW=10000
> >> -Dorg.apache.kahadb.journal.CALLER_BUFFER_APPENDER=true
> >>
> >> Are these type of values recommended for when one is dealing with
> >> persistent messages backed by slow storage?
> >>
> >> If not, can someone provide recommended scenarios when these values
> should
> >> be adjusted (per the unit test example above)?
> >>
> >> Thanks,
> >> Paul
> >>
> >
> >
> >
> > --
> > *Christian Posta*
> > http://www.christianposta.com/blog
> > twitter: @christianposta
>
>
>
> --
> http://redhat.com
> http://blog.garytully.com
>

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