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From vineet daniel <vineetdan...@gmail.com>
Subject Re: bloom filter
Date Fri, 07 May 2010 11:03:56 GMT
1. Peter said 'without going to disk' so that means bloom filters reside in
memory, always or just when request to that particular CF is made.
2. "It is also important for identifying which SSTable files to look inside
even when a key is present." - David can you please throw some more light on
your point, like what are the implications, why do we need to identify etc.


_______________________________________
Vineet Daniel
_______________________________________

Let your email find you....


On Fri, May 7, 2010 at 4:28 PM, David Strauss <david@fourkitchens.com>wrote:

> On 2010-05-07 10:55, Peter Schüller wrote:
> >> what is the benefit of creating bloom filter when cassandra writes data,
> how
> >> does it helps ?
> >
> > It allows Cassandra to answer requests for non-existent keys without
> > going to disk, except in cases where the bloom filter gives a false
> > positive.
> >
> > See:
> >
> >
> http://spyced.blogspot.com/2009/01/all-you-ever-wanted-to-know-about.html
>
> It is also important for identifying which SSTable files to look inside
> even when a key is present.
>
> --
> David Strauss
>   | david@fourkitchens.com
> Four Kitchens
>   | http://fourkitchens.com
>   | +1 512 454 6659 [office]
>   | +1 512 870 8453 [direct]
>
>

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