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Date: Mon, 14 Sep 2015 18:59:02 -0700
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 <CAEuTtQptQ=HD=hAHqQft6LupDcJyeHM7MrCfvNZto=igiWh6Uw@mail.gmail.com>
Subject: Source code for bootstrap process
From: Aadil Ahamed <aadil.ahamed@gmail.com>
To: dev@cassandra.apache.org
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Hi,
I am interested in understanding the quantitative effect of adding a node
to a Cassandra cluster. From my tests I have observed that the CPU usage on
an added node is relatively high when data is being streamed in to it while
bootstrapping.

For example, here is a graph for a node that was added to a 4 node cluster
(I can insert images right?):


=E2=80=8B
As you can see, the cpu usage stays pretty high while data is streamed into
the node.

I attached a JVM profiler: https://github.com/aragozin/jvm-tools
<https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__github.com_aragozin=
_jvm-2Dtools&d=3DBQMF-g&c=3D96ZbZZcaMF4w0F4jpN6LZg&r=3DIPrliSk1Ijg-U4peH4II=
W6Lcj4i6GMuxpxu3zDH-l0w&m=3DbZUdJplcHM5O0utN6k29Q7-osMmhK8tYqLUvl_xhTFg&s=
=3DrzUSlUgnPe1HeHl5iM4Uktrz2KExlXdNyNMmgcnQlus&e=3D>
(recommended
by one of the members of the Cassandra user mailing list) to try and figure
out what exactly was taking up so much cpu.

Here is a snapshot of the profiler when cpu usage was high:

=E2=80=8BThe threads "STREAM-IN-/IP_ADDRESS" seem to be the most cpu intens=
ive.
Why are these threads so cpu intensive?
Can you point me to the source code where these threads are implemented?

(My Cassandra Version is 2.1.7)

--=20

Thank you,
Aadil Ahamed

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<div dir=3D"ltr">Hi,<div>I am interested in understanding the quantitative =
effect of adding a node to a Cassandra cluster. From my tests I have observ=
ed that the CPU usage on an added node is relatively high when data is bein=
g streamed in to it while bootstrapping.</div><div><br></div><div>For examp=
le, here is a graph for a node that was added to a 4 node cluster (I can in=
sert images right?):</div><div><br></div><div><img src=3D"cid:ii_iekp20do0_=
14fceaa584d2fd34" width=3D"544" height=3D"408"><br>=E2=80=8B<br></div><div>=
As you can see, the cpu usage stays pretty high while data is streamed into=
 the node.</div><div><br></div><div>I attached a JVM profiler:=C2=A0<span c=
lass=3D""><a href=3D"https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A_=
_github.com_aragozin_jvm-2Dtools&amp;d=3DBQMF-g&amp;c=3D96ZbZZcaMF4w0F4jpN6=
LZg&amp;r=3DIPrliSk1Ijg-U4peH4IIW6Lcj4i6GMuxpxu3zDH-l0w&amp;m=3DbZUdJplcHM5=
O0utN6k29Q7-osMmhK8tYqLUvl_xhTFg&amp;s=3DrzUSlUgnPe1HeHl5iM4Uktrz2KExlXdNyN=
MmgcnQlus&amp;e=3D">https://github.com/aragozin/jvm-tools</a></span><span c=
lass=3D"">=C2=A0(recommended by one of the members of the Cassandra user ma=
iling list) to try and figure out what exactly was taking up so much cpu.</=
span></div><div><span class=3D""><br></span></div><div><span class=3D"">Her=
e is a snapshot of the profiler when cpu usage was high:</span></div><div><=
span class=3D""><img src=3D"cid:ii_iekpi52j1_14fceb5d4c8df54a" width=3D"544=
" height=3D"356"><br>=E2=80=8BThe threads &quot;STREAM-IN-/IP_ADDRESS&quot;=
 seem to be the most cpu intensive.=C2=A0</span></div><div><span class=3D""=
>Why are these threads so cpu intensive?</span></div><div><span class=3D"">=
Can you point me to the source code where these threads are implemented?</s=
pan></div>


<div><br></div><div>(My Cassandra Version is 2.1.7)</div><div><div><br></di=
v>-- <br><div class=3D"gmail_signature"><div><br></div>Thank you,<div>Aadil=
 Ahamed</div></div>
</div></div>

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