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Date: Tue, 6 Oct 2009 11:41:06 -0500
Message-ID: <e06563880910060941m6e4cd508p6da335f4c4373d22@mail.gmail.com>
Subject: Re: Storage proxy write latency is too high
From: Jonathan Ellis <jbellis@gmail.com>
To: cassandra-user@incubator.apache.org
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Very interesting.  Thanks for figuring that out.

-Jonathan

On Tue, Oct 6, 2009 at 11:14 AM, Igor Katkov <ikatkov@gmail.com> wrote:
> I think I finally found what. It's implementation of Java NIOon Windows (=
JVM
> 1.6.0.16, 64b on Windows 2003)
> The very same code, same network but CentOS linux gives almost 4x
> performance. (in Cassandra@linux -> Cassandra@Windows setup)
> I don't have another linux box to test (Cassandra@linux -> Cassandra@linu=
x)
> performance, but expect it to be even better.
>
> A lesson learnt: don't use windows.
>
> P.S.
> Here at Viigo we also learnt the hard way that=A0 async IO is also broken=
 in
> .NET (C#). Now I start to wonder if there is some fundamental flaw in asy=
nc
> IO on windows...
>
> On Mon, Oct 5, 2009 at 3:23 PM, Jonathan Ellis <jbellis@gmail.com> wrote:
>>
>> On Mon, Oct 5, 2009 at 2:17 PM, Igor Katkov <ikatkov@gmail.com> wrote:
>> > measured via JMX console i.e. does not include client-cassandra-client
>> > latency
>> >
>> > 20 client threads 176975b value StorageProxy.WriteLatency ~660ms
>> > 10 client threads 176975b value StorageProxy.WriteLatency ~350ms
>> > 05 client threads 176975b value StorageProxy.WriteLatency ~156ms
>>
>> this is going up basically linearly with amount of (data x clients),
>> so clearly something is getting saturated.
>
>