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From Gary Tully <gary.tu...@gmail.com>
Subject Re: kahadb system property configuration options
Date Fri, 28 Jun 2013 12:27:35 GMT
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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