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From Maxim Potekhin <potek...@bnl.gov>
Subject Re: read performance problem
Date Sun, 20 Nov 2011 02:50:30 GMT
Try to see if there is a lot of paging going on,
and run some benchmarks on the disk itself.
Are you running Windows or Linux? Do you think
the disk may be fragmented?


Maxim


On 11/19/2011 8:58 PM, Kent Tong wrote:
> Hi,
>
> On my computer with 2G RAM and a core 2 duo CPU E4600 @ 2.40GHz, I am 
> testing the
> performance of Cassandra. The write performance is good: It can write 
> a million records
> in 10 minutes. However, the query performance is poor and it takes 10 
> minutes to read
> 10K records with sequential keys from 0 to 9999 (about 100 QPS). 
> This is far away from
> the 3,xxx QPS found on the net.
>
> Cassandra decided to use 1G as the Java heap size which seems to be 
> fine as at the end
> of the benchmark the swap was barely used (only 1M used).
>
> I understand that my computer may be not as powerful as those used in 
> the other benchmarks,
> but it shouldn't be that far off (1:30), right?
>
> Any suggestion? Thanks in advance!
>


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