2010/4/7 Peter Schüller :
> Bloom filters are by their very nature lossy in the sense that you
> cannot determine later what you put into it. Re-sizing a bloom filter
> implies re-creating it from scratch. I'm not sure what cassandra does
> however.
Since our data files are immutable we don't have
2010/4/7 Peter Schüller :
> (bloomfilters, not boonfilters)
>
> Speaking in general, not specific to cassandra:
>
>> 2. Are boonfilters a fixed size, or they adjust as to the # of keys? any
>> example size?
>
> Bloom filters are by their very nature lossy in the sen
> 1. Is the only place boonfilters are used in Cassandra is when you want to
> see if a particular key exists in a particular node?
Each node stores a set of SSTables locally, each with a BloomFilter attached:
the filters are used to check whether a particular SSTable contains information
o.html
>
> On Wed, Apr 7, 2010 at 1:27 PM, S Ahmed wrote:
>> Just reading up on boonfilters, few questions.
>>
>> Basically boonfilters let give you a true/false if a particular key exists,
>> and they *may* give you a false positive i.e. they key exists but never a
&g
On 2010-04-07 20:34, Peter Schüller wrote:
> Re-sizing a bloom filter implies re-creating it from scratch.
Not necessarily. Depending on your hash, you can sometimes shrink
without regeneration (and without other penalties). It's also sometimes
possible to enlarge the bloom filter without regenera
Please read this:
http://www.allthingsdistributed.com/2007/10/amazons_dynamo.html
On Wed, Apr 7, 2010 at 1:27 PM, S Ahmed wrote:
> Just reading up on boonfilters, few questions.
>
> Basically boonfilters let give you a true/false if a particular key exists,
> and they *may* give
2010/4/7 Peter Schüller :
> Someone correct me if I'm wrong, but my understanding is that the
> bloom filters are only used to optimize the case of a key being
> non-existent, such that you only have to go down on disk for a very
> small number of requests for non-existent keys. I do not believe bl
(bloomfilters, not boonfilters)
Speaking in general, not specific to cassandra:
> 2. Are boonfilters a fixed size, or they adjust as to the # of keys? any
> example size?
Bloom filters are by their very nature lossy in the sense that you
cannot determine later what you put into it. Re-si
Bloomfilters I think is what you mean- correct?
Sent from my iPhone
On Apr 7, 2010, at 3:27 PM, "S Ahmed" wrote:
Just reading up on boonfilters, few questions.
Basically boonfilters let give you a true/false if a particular key
exists,
and they *may* give you a false positive
Just reading up on boonfilters, few questions.
Basically boonfilters let give you a true/false if a particular key exists,
and they *may* give you a false positive i.e. they key exists but never a
false negative i.e. the key doesn't exist.
The core of boonfilters is its hashing mechanism
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