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From Mohit Anchlia <mohitanch...@gmail.com>
Subject Re: how to reduce disk read? (and bloom filter performance)
Date Fri, 07 Oct 2011 13:55:58 GMT
Check your disk utilization using iostat. Also, check if compactions
are causing reads to be slow. Check GC too.

You can look at cfhistograms output or post it here.

On Fri, Oct 7, 2011 at 1:44 AM, Radim Kolar <hsn@sendmail.cz> wrote:
> Dne 7.10.2011 10:04, aaron morton napsal(a):
>>
>> Of the top of my head I it's not exposed via nodetool.
>>
>
>> You can get it via HTTP if you install mx4j or if you could try
>> http://wiki.cyclopsgroup.org/jmxterm
>
> i have MX4J/Http but cant find that info in listing.
>
> i suspect that bloom filter performance is not so great on my 30GB CFs
> because one read is 44.846ms on machine without any workload and because CF
> has only single column and rarely (less that 0.01%) updated, data should not
> be in more than 1 ssfile.
>
> it should be 2 reads: one read to -Index and  second to read to -Data: about
> 24 ms, but its double.
>
> I can also confirm other ppl experience that performance really drops after
> inserting more then 500k columns.
>

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