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From Ryan King <r...@twitter.com>
Subject Re: High BloomFilterFalseRation
Date Wed, 27 Oct 2010 16:41:58 GMT
On Wed, Oct 27, 2010 at 3:24 AM, Daniel Doubleday
<daniel.doubleday@gmx.net> wrote:
> Hi people
>
> We are currently moving our second use case from mysql to cassandra. While importing
the data (ongoing) I noticed that the BloomFilterFalseRation seems to be pretty high compared
to another CF which is in used in production right now.
>
> Its a hierarchical data model and I cannot avoid to do a read before inserting multiple
columns.
>
> I see a false positive ration of 0.28 while in my other CF it is 0.00025.
>
> The CF has 5 live sstables whiel I read that ratio. At that time I inserted ~ 200k rows
with a total of 1M cols. Row keys are pretty large unfortunately (key.length() ~ 60)
>
> Just wanted to check if this value is to be expected.

This is not expected. How big are the bloom filters on disk?

-ryan

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