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From Mohit Anchlia <mohitanch...@gmail.com>
Subject Re: how to reduce disk read? (and bloom filter performance)
Date Mon, 17 Oct 2011 22:38:34 GMT
On Sun, Oct 16, 2011 at 2:20 AM, Radim Kolar <hsn@sendmail.cz> wrote:
> Dne 10.10.2011 18:53, Mohit Anchlia napsal(a):
>>
>> Does it mean you are not updating a row or deleting them?
>
> yes. i have 350m rows and only about 100k of them are updated.
>>
>>  Can you look at JMX values of
>>
>> BloomFilter* ?
>
> i could not find this in jconsole mbeans or in jmx over http in cassandra
> 1.0

Look in jconcole -> org.apache.cassandra.db -> ColumnFamilies

>
> I believe if you want to keep disk seeks to 1 ssTable you will need to
> compact more often.
>
> cassandra have max 2 disk seeks per 1 sstable read. one seek for index,
> second seek for data. If bloom filters are working fine, in my case there is
> no need to access more than 1 sstable.
>

unless your updates to a row are spread accross multiple uncompacted ssTables.

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