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Date: Sun, 20 Nov 2011 16:54:18 -0500
Message-ID: 
 <CANNh1xqYg78PxP=oOFCV_6HcE1iUT52zDBYFdGZtYbqaR7Zm-w@mail.gmail.com>
Subject: Re: What sort of load do the tombstones create on the cluster?
From: Jahangir Mohammed <md.jahangir27@gmail.com>
To: user@cassandra.apache.org, potekhin@bnl.gov
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Mostly, they are I/O and CPU intensive during major compaction. If ganglia
doesn't have anything suspicious there, then what is performance loss ?
Read or write?
On Nov 17, 2011 1:01 PM, "Maxim Potekhin" <potekhin@bnl.gov> wrote:

> In view of my unpleasant discovery last week that deletions in Cassandra
> lead to a very real
> and serious performance loss, I'm working on a strategy of moving forward.
>
> If the tombstones do cause such problem, where should I be looking for
> performance bottlenecks?
> Is it disk, CPU or something else? Thing is, I don't see anything
> outstanding in my Ganglia plots.
>
> TIA,
>
> Maxim
>
>

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<p>Mostly, they are I/O and CPU intensive during major compaction. If gangl=
ia doesn&#39;t have anything suspicious there, then what is performance los=
s ? Read or write?</p>
<div class=3D"gmail_quote">On Nov 17, 2011 1:01 PM, &quot;Maxim Potekhin&qu=
ot; &lt;<a href=3D"mailto:potekhin@bnl.gov">potekhin@bnl.gov</a>&gt; wrote:=
<br type=3D"attribution"><blockquote class=3D"gmail_quote" style=3D"margin:=
0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
In view of my unpleasant discovery last week that deletions in Cassandra le=
ad to a very real<br>
and serious performance loss, I&#39;m working on a strategy of moving forwa=
rd.<br>
<br>
If the tombstones do cause such problem, where should I be looking for perf=
ormance bottlenecks?<br>
Is it disk, CPU or something else? Thing is, I don&#39;t see anything outst=
anding in my Ganglia plots.<br>
<br>
TIA,<br>
<br>
Maxim<br>
<br>
</blockquote></div>

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