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Date: Thu, 4 Aug 2011 20:22:19 -0400
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 <CACU4Y-jMMOpyQvDzM2sF4AzxNa2Fkb0ttiFpkCdovRpCb5WYBA@mail.gmail.com>
Subject: Re: Force a garbage collection with jmxterm from the shell
From: Jeffrey Kesselman <jeffpk@gmail.com>
To: user@cassandra.apache.org
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Technically, by the VM spec, you can never *force* a java VM to garbage
collect.  You can request, but thats it.

Rather then open that whole debate again if anyone doubts this, i suggets
they look back in the archives.

JK


On Thu, Aug 4, 2011 at 6:35 PM, Teijo Holzer <tholzer@wetafx.co.nz> wrote:

> Hi,
>
> The following command line triggers a garbage collection via JMX:
>
> echo 'run -b java.lang:type=Memory gc' | java -jar
> jmxterm-1.0-alpha-4-uber.jar -l service:jmx:rmi:///jndi/rmi://**hostname:8080/jmxrmi
> -n
>
> It uses:
>
> http://wiki.cyclopsgroup.org/**jmxterm<http://wiki.cyclopsgroup.org/jmxterm>
>
> The GC is necessary after a major compaction to trigger the deletion of
> stale files.
>
> jmxterm can also be used to query and modify beans exposed via JMX. That
> makes it easy to integrate into any monitoring & maintenance scripts, e.g.:
>
> echo 'get -b org.apache.cassandra.db:type=**ColumnFamilies,keyspace=KS1,**columnfamily=CF1
> ReadCount' | ...
>
> You can also perform multiple operations as once:
>
> echo 'domains\nbeans' | ...
>
> If you are concerned about the start-up speed of the jar, just unpack it.
> You might need to unpack & shuffle the internal jars around a bit as well.
>
> Cheers,
>
>        T.
>


-- 
It's always darkest just before you are eaten by a grue.

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Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

Technically, by the VM spec, you can never *force* a java VM to garbage col=
lect. =A0You can request, but thats it.<div><br></div><div>Rather then open=
 that=A0whole=A0debate again if=A0anyone=A0doubts this, i suggets they look=
 back in the archives.</div>
<div><br></div><div>JK<br><div><br></div><div><br><br><div class=3D"gmail_q=
uote">On Thu, Aug 4, 2011 at 6:35 PM, Teijo Holzer <span dir=3D"ltr">&lt;<a=
 href=3D"mailto:tholzer@wetafx.co.nz">tholzer@wetafx.co.nz</a>&gt;</span> w=
rote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex;">Hi,<br>
<br>
The following command line triggers a garbage collection via JMX:<br>
<br>
echo &#39;run -b java.lang:type=3DMemory gc&#39; | java -jar jmxterm-1.0-al=
pha-4-uber.jar -l service:jmx:rmi:///jndi/rmi://<u></u>hostname:8080/jmxrmi=
 -n<br>
<br>
It uses:<br>
<br>
<a href=3D"http://wiki.cyclopsgroup.org/jmxterm" target=3D"_blank">http://w=
iki.cyclopsgroup.org/<u></u>jmxterm</a><br>
<br>
The GC is necessary after a major compaction to trigger the deletion of sta=
le files.<br>
<br>
jmxterm can also be used to query and modify beans exposed via JMX. That ma=
kes it easy to integrate into any monitoring &amp; maintenance scripts, e.g=
.:<br>
<br>
echo &#39;get -b org.apache.cassandra.db:type=3D<u></u>ColumnFamilies,keysp=
ace=3DKS1,<u></u>columnfamily=3DCF1 ReadCount&#39; | ...<br>
<br>
You can also perform multiple operations as once:<br>
<br>
echo &#39;domains\nbeans&#39; | ...<br>
<br>
If you are concerned about the start-up speed of the jar, just unpack it. Y=
ou might need to unpack &amp; shuffle the internal jars around a bit as wel=
l.<br>
<br>
Cheers,<br><font color=3D"#888888">
<br>
 =A0 =A0 =A0 =A0T.<br>
</font></blockquote></div><br><br clear=3D"all"><br>-- <br>It&#39;s always =
darkest just before you are eaten by a grue.<br>
</div></div>

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