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Date: Sun, 3 Apr 2011 20:01:50 +0800
Message-ID: <BANLkTimLajQSk4nMnGh-5x+khG+1TK3VjA@mail.gmail.com>
Subject: Re: compaction behaviour
From: Zhu Han <schumi.han@gmail.com>
To: user@cassandra.apache.org
Cc: Anurag Gujral <anurag.gujral@gmail.com>
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best regards,
Zhu Han


On Sun, Apr 3, 2011 at 9:21 AM, Anurag Gujral <anurag.gujral@gmail.com>wrote:

> Hi All,
>            I have loaded data into cassandra using batch processing  the
> response times for reads are in the range of  0.8 ms but I am using SSDs. so
> I expect the read times to be even faster.
>

Does your working set fit in the memory? If so, SSD is not helpful to reduce
the latency.


> Every time I run compaction the latency numbers reduce to 0.3 to 0.4ms  ,
> is there a way I can run compaction once with some parameters
> so that i can get the same numbers 0.3 to 0.4 ms for reads.
> Please note that I am not loading the data again.
>
> Thanks
> Anurag
>

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<br clear=3D"all">best regards,<br>Zhu Han<br><br>
<br><br><div class=3D"gmail_quote">On Sun, Apr 3, 2011 at 9:21 AM, Anurag G=
ujral <span dir=3D"ltr">&lt;<a href=3D"mailto:anurag.gujral@gmail.com">anur=
ag.gujral@gmail.com</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_quo=
te" style=3D"margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204=
, 204); padding-left: 1ex;">
Hi All,<div>=A0=A0 =A0 =A0 =A0 =A0 I have loaded data into cassandra using =
batch processing =A0the response times for reads are in the range of =A00.8=
 ms but I am using SSDs.=A0so I expect the read times to be even faster.</d=
iv></blockquote>
<div><br>Does your working set fit in the memory? If so, SSD is not helpful=
 to reduce the latency.<br>=A0<br></div><blockquote class=3D"gmail_quote" s=
tyle=3D"margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204=
); padding-left: 1ex;">
<div>Every time I run compaction the latency numbers reduce to 0.3 to 0.4ms=
 =A0, is there a way I can run compaction once with some parameters=A0</div=
>
<div>so that i can get the same numbers 0.3 to 0.4 ms for reads.</div><div>=
Please note that I am not loading the data again.</div><div><br></div><div>=
Thanks</div><div>Anurag</div>
</blockquote></div><br>

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