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From Radim Kolar <...@sendmail.cz>
Subject Re: how to reduce disk read? (and bloom filter performance)
Date Sun, 09 Oct 2011 14:09:28 GMT
Dne 7.10.2011 23:16, Mohit Anchlia napsal(a):
> You'll see output like:
>
> Offset      SSTables
> 1                  8021
> 2                  783
>
> Which means 783 read operations accessed 2 SSTables
thank you for explaining it to me. I see this:

Offset      SSTables
1              59323
2                857
3                  56

it means bloom filter failure ratio over 1%. Cassandra in unit tests 
expects bloom filter false positive less than 1.05%. HBase has 
configurable bloom filters. You can choose 1% or 0.5% - it can make 
difference for large cache.

But result is that my poor read performance should not be caused by 
bloom filters.

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