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From Franc Carter <franc.car...@sirca.org.au>
Subject Re: keycache persisted to disk ?
Date Mon, 13 Feb 2012 08:58:17 GMT
On Mon, Feb 13, 2012 at 7:49 PM, Peter Schuller <peter.schuller@infidyne.com
> wrote:

> > I'm making an assumption . . .  I don't yet know enough about cassandra
> to
> > prove they are in the cache. I have my keycache set to 2 million, and am
> > only querying ~900,000 keys. so after the first time I'm assuming they
> are
> > in the cache.
>
> Note that the key cache only caches the index positions in the data
> file, and not the actual data. The key cache will only ever eliminate
> the I/O that would have been required to lookup the index entry; it
> doesn't help to eliminate seeking to get the data (but as usual, it
> may still be in the operating system page cache).
>

Yep - I haven't enabled row caches, my calculations at the moment indicate
that the hit-ratio won't be great - but I'll be testing that later


>
> --
> / Peter Schuller (@scode, http://worldmodscode.wordpress.com)
>



-- 

*Franc Carter* | Systems architect | Sirca Ltd
 <marc.zianideferranti@sirca.org.au>

franc.carter@sirca.org.au | www.sirca.org.au

Tel: +61 2 9236 9118

Level 9, 80 Clarence St, Sydney NSW 2000

PO Box H58, Australia Square, Sydney NSW 1215

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