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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Experiences with Cassandra hardware planning
Date Tue, 26 Oct 2010 03:31:17 GMT
On Mon, Oct 25, 2010 at 3:10 PM, Eric Rosenberry <eric@rosenberry.org> wrote:
>> I don't follow the reasoning there.  Row cache or fs cache, it will be
>> hot after reading it once, the difference is that doing a read to the
>> cached data is much faster from row cache.
>
> Yeah, I would have thought the same.  Benjamin Black actually recommended we
> go this route as with our dataset (we have huge numbers of super-tiny rows)
> it would take weeks of running for the row cache to become useful.

Sounds like the assumption is that the FS cache's guessing that if one
row from a data page is hot, the rest of the page will too, will be
helpful.  Depending on your workload it may help, or it may be
counterproductive. :)

-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

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