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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: perfomance issue
Date Fri, 25 Sep 2009 15:32:55 GMT
It's impossible to say given what you have told us.

Step zero in benchmarking cassandra is turning the log level to INFO.
Step one is testing on a machine where you can put the commitlog
directory on its own disk.

It's true that frequently cassandra will be slower than custom code
writing to local disk, but that's not the interesting part of what
cassandra does. :)

-Jonathan

On Fri, Sep 25, 2009 at 10:23 AM, Kirill A. Korinskiy
<catap+cassandra@catap.ru> wrote:
> Hello.
>
> I'm write a small erlang benchmark: cassandra vs simple fs storage and
> I have a results:
>
> fs_storage:
> 10: 1732/228633/2873/1128 992/233261/2870/1026
> 25: 4531/35290/6084/632 1786/35292/5969/312
> 50: 4707/311825/13694/4644 1366/382913/14470/5823
>
> cassandra:
> 10: 69014/424051/145871/28066 9553/427823/141925/29190
> 25: 165500/536108/339736/77173 14846/710370/341819/78694
> 50: 325790/1050753/667931/157962 9865/1033461/676317/160606
>
> legends:
> parallel request: get set min/max/avg/mad
>
> So. Cassandra slower ~50 times.
>
> Ok I change cassandra setting:
>
>  ColumnFamily from UTF8Type to BytesType
>  MemtableObjectCountInMillions from 0.1 to 1
>  ConcurrentReads from 8 to 64
>  ConcurrentWrites from 32 to 64
>
> And I have:
>
> fs_storage:
> 10: 2164/245375/2515/474 651/247790/2746/800
> 25: 5521/19959/5838/196 1836/20138/5943/186
> 50: 6369/32837/11476/944 1396/32818/11449/876
>
> cassandra:
> 10: 39931/279903/48463/4812 21378/278782/51477/4526
> 25: 101911/407343/119135/9158 8794/410423/123768/9076
> 50: 209202/429959/238179/12180 7803/442580/244402/13443
>
> Cassandra slower ~20 times.
>
> I's normal? Can I do something wrong? Maybe you have any ideas?
>
> --
> wbr, Kirill
>

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