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Posted to user@cassandra.apache.org by ring_ayumi_king <ri...@yahoo.com.tw> on 2010/08/25 08:52:26 UTC

Does the scan speed with CL.ALL is faster than CL.QUORUM and CL.ONE?

Hi all,

I ran my benchmark(OPP via get_range_slices) and found the following:
Why does the scan speed with CL.ALL is faster than CL.QUORUM and CL.ONE?

CL.ONE (1k per row, Count:50000)
scan :11095 ms
scan per:0.2219 ms
scan thput:4506.5347 ops/sec

CL.QUORUM
scan :11072 ms
scan per:0.22144 ms
scan thput:4515.896 ops/sec

CL.ALL
scan :7869 ms
scan per:0.15738 ms
scan thput:6354.0474 ops/sec

Thanks.

Shen

Re: Does the scan speed with CL.ALL is faster than CL.QUORUM and CL.ONE?

Posted by Benjamin Black <b...@b3k.us>.

Did you run the tests in this order without changing anything but CL?
You may be seeing the effects of OS page caching.  Run then in the
reverse order and see if the difference persists.

On Tue, Aug 24, 2010 at 11:52 PM, ring_ayumi_king
<ri...@yahoo.com.tw> wrote:
> Hi all,
>
> I ran my benchmark(OPP via get_range_slices) and found the following:
> Why does the scan speed with CL.ALL is faster than CL.QUORUM and CL.ONE?
>
> CL.ONE (1k per row, Count:50000)
> scan :11095 ms
> scan per:0.2219 ms
> scan thput:4506.5347 ops/sec
>
> CL.QUORUM
> scan :11072 ms
> scan per:0.22144 ms
> scan thput:4515.896 ops/sec
>
> CL.ALL
> scan :7869 ms
> scan per:0.15738 ms
> scan thput:6354.0474 ops/sec
>
> Thanks.
>
> Shen
>
>
>
>