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From DV <vind...@gmail.com>
Subject Re: KahaDB disk utilization
Date Wed, 26 Sep 2012 03:14:13 GMT
Are you absolutely certain that there are exactly 10M messages on the
broker? I've seen a huge KahaDB store with only a few messages in the
queue because the earlier published messages weren't de-queued
("stuck" messages).

On the other hand, maybe KahaDB sacrifices space for performance, kind
of like MongoDB does.

- DV

On Wed, Sep 19, 2012 at 8:29 AM, Oleg Dulin <oleg.dulin@gmail.com> wrote:
> Dear Distinguished Colleagues:
>
> I've been trying to understand something.
>
> My queues take Java object messages. Serialized into bytes, each Java object
> is about 1.5K on average.
>
> When I have a backlog of 10 million objects on one of the queues, the disk
> utilization of kahadb is around 50gigs. But this math here:
>
> groovy:000> 1500*10000000/1024/1024/1024;
> ===> 1.9698386192
>
> means that 10M objects should only take up less than 2gigs.
>
> Even if I had 3 queues going with the same objects, the total would be 6gigs
> max. So why the disk utilization overhead ? How much does a single JMS
> message need ?
>
>
> --
> Regards,
> Oleg Dulin
> NYC Java Big Data Engineer
> http://www.olegdulin.com/
>
>



-- 
Best regards, Dmitriy V.

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