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From Kirill A. Korinskiy <catap+cassan...@catap.ru>
Subject Re: perfomance issue
Date Fri, 25 Sep 2009 15:46:28 GMT
At Fri, 25 Sep 2009 10:34:06 -0500,
Michael Greene <michael.greene@gmail.com> wrote:
> 
> Thanks for the results.  Perhaps you could shed further light:
> Is this a single node system?

Ooops. I'm missing.

Nope. It's a cluster. I use a 3 node and ReplicationFactor set to 2.

> Is the log level changed from DEBUG to INFO?

I'm switching off all logs.

> Are the commit log and data directories on the same drive?

Yes, all data on same disk.

> Are the sets/gets being processed interleaved in parallel, or one then the other?

I'm using 10/25/50 parallel request to cluster. My erlang wrapper send
one request to one node and chose node by round robin scheduling.

I'm set values with cassandra_ALL and after setting get by cassandra_QUORUM.

> Note that writes are ~6x and ~5x slower with those values, and gets are ~50x and ~20x
> slower
> 
> Michael
> 
> 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
> 
> 

-- 
wbr, Kirill

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