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Date: Mon, 26 Apr 2010 00:09:15 +0700
Message-ID: <y2yf65ba8d01004251009v98914273wb9a16d3fecc03b65@mail.gmail.com>
Subject: Re: Cassandra - Thread leak when high concurrent load
From: JKnight JKnight <beuknight@gmail.com>
To: user@cassandra.apache.org
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Thanks Robson,

The number of thread gradually increase to 7000. And the server hang up.
I know threadpool is used to prevent creating large number of thread.

So why Cassandra create large number of thread when high concurrent load.

On Sun, Apr 25, 2010 at 5:38 PM, Mark Robson <markxr@gmail.com> wrote:

>
>
> On 25 April 2010 10:48, JKnight JKnight <beuknight@gmail.com> wrote:
>
>> Dear all,
>>
>> My Cassandra server had thread leak when high concurrent load. I used
>> jconsole and saw many, many thread occur.
>>
>
> Just because there are a lot of threads, need not imply a thread leak.
> Cassandra uses a lot of threads.
>
> Do you see the number of threads gradually increase during a soak test on
> your test cluster? Can you dump the JVM info (I believe sending a signal
> makes it dump this)?
>
> The JMX information viewable via JConsole also gives you a list of threads.
> Assuming you see this gradually increasing during the soak test, can you
> tellwhich thread pool is increasing?
>
> Mark
>


-- 
Best regards,
JKnight

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Thanks Robson, <br><br>The number of thread gradually increase to 7000. And=
 the server hang up. <br>I know threadpool is used to prevent creating larg=
e number of thread.<br><br>So why Cassandra create large number of thread w=
hen high concurrent load.<br>
<br><div class=3D"gmail_quote">On Sun, Apr 25, 2010 at 5:38 PM, Mark Robson=
 <span dir=3D"ltr">&lt;<a href=3D"mailto:markxr@gmail.com">markxr@gmail.com=
</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_quote" style=3D"border=
-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-lef=
t: 1ex;">
<br><br><div class=3D"gmail_quote"><div class=3D"im">On 25 April 2010 10:48=
, JKnight JKnight <span dir=3D"ltr">&lt;<a href=3D"mailto:beuknight@gmail.c=
om" target=3D"_blank">beuknight@gmail.com</a>&gt;</span> wrote:<br><blockqu=
ote class=3D"gmail_quote" style=3D"border-left: 1px solid rgb(204, 204, 204=
); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">

Dear all, <br><br>My Cassandra server had thread leak when high concurrent =
load. I used jconsole and saw many, many thread occur.<br></blockquote><div=
><br></div></div><div>Just because there are a lot of threads, need not imp=
ly a thread leak. Cassandra uses a lot of threads.</div>

<div><br></div><div>Do you see the number of threads gradually increase dur=
ing a soak test on your test cluster? Can you dump the JVM info (I believe =
sending a signal makes it dump this)?</div><div><br></div><div>The JMX info=
rmation viewable via JConsole also gives you a list of threads. Assuming yo=
u see this gradually increasing during the soak test, can you tellwhich thr=
ead pool is increasing?</div>

<div><br></div><font color=3D"#888888"><div>Mark</div></font></div>
</blockquote></div><br><br clear=3D"all"><br>-- <br>Best regards,<br>JKnigh=
t<br>

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