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From Chris Lohfink <clohfin...@gmail.com>
Subject Re: jmxterm "#NullPointerException: No such PID "
Date Thu, 20 Sep 2018 19:18:29 GMT
For what its worth, I highly recommend you remove that option in all
cassandra clusters first thing. A possibly non existent improvement (ie
/tmp on different low throughput drive) vs being able to diagnose issues is
a no brainer. You can measure or monitor gc logs for your safepoint pauses
to see if its ever a significant portion of your GC pauses.

Chris

On Thu, Sep 20, 2018 at 6:05 AM Philip Ó Condúin <philipoconduin@gmail.com>
wrote:

> Thank you Yuki, this explains it.
> I am used to working on C* 2.1 in production where this JVM flag is not
> enabled.
>
>
> On Wed, 19 Sep 2018 at 00:29, Yuki Morishita <mor.yuki@gmail.com> wrote:
>
>> This is because Cassandra sets -XX:+PerfDisableSharedMem JVM option by
>> default.
>> This prevents tools such as jps to list jvm processes.
>> See https://issues.apache.org/jira/browse/CASSANDRA-9242 for detail.
>>
>> You can work around by doing what Riccardo said.
>> On Tue, Sep 18, 2018 at 9:41 PM Philip Ó Condúin
>> <philipoconduin@gmail.com> wrote:
>> >
>> > Hi Riccardo,
>> >
>> > Yes that works for me:
>> >
>> > Welcome to JMX terminal. Type "help" for available commands.
>> > $> open localhost:7199
>> > #Connection to localhost:7199 is opened
>> > $>domains
>> > #following domains are available
>> > JMImplementation
>> > ch.qos.logback.classic
>> > com.sun.management
>> > java.lang
>> > java.nio
>> > java.util.logging
>> > org.apache.cassandra.db
>> > org.apache.cassandra.hints
>> > org.apache.cassandra.internal
>> > org.apache.cassandra.metrics
>> > org.apache.cassandra.net
>> > org.apache.cassandra.request
>> > org.apache.cassandra.service
>> > $>
>> >
>> > I can work with this :-)
>> >
>> > Not sure why the JVM is not listed when issuing the JVMS command, maybe
>> its a server setting, our production servers find the Cass JVM.  I've spent
>> half the day trying to figure it out so I think I'll just put it to bed now
>> and work on something else.
>> >
>> > Regards,
>> > Phil
>> >
>> > On Tue, 18 Sep 2018 at 13:34, Riccardo Ferrari <ferrarir@gmail.com>
>> wrote:
>> >>
>> >> Hi Philip,
>> >>
>> >> I've used jmxterm myself without any problems particular problems. On
>> my systems too, I don't get the cassandra daemon listed when issuing the
>> `jvms` command but I never spent much time investigating it.
>> >> Assuming you have not changed anything relevant in the
>> cassandra-env.sh you can connect using jmxterm by issuing 'open
>> 127.0.0.1:7199'. Would that work for you?
>> >>
>> >> HTH,
>> >>
>> >>
>> >>
>> >> On Tue, Sep 18, 2018 at 2:00 PM, Philip Ó Condúin <
>> philipoconduin@gmail.com> wrote:
>> >>>
>> >>> Further info:
>> >>>
>> >>> I would expect to see the following when I list the jvm's:
>> >>>
>> >>> Welcome to JMX terminal. Type "help" for available commands.
>> >>> $>jvms
>> >>> 25815    (m) - org.apache.cassandra.service.CassandraDaemon
>> >>> 17628    ( ) - jmxterm-1.0-alpha-4-uber.jar
>> >>>
>> >>> But jmxtem is not picking up the JVM for Cassandra for some reason.
>> >>>
>> >>> Can someone point me in the right direction?  Is there settings in
>> the cassandra-env.sh file I need to amend to get jmxterm to find the cass
>> jvm?
>> >>>
>> >>> Im not finding much about it on google.
>> >>>
>> >>> Thanks,
>> >>> Phil
>> >>>
>> >>>
>> >>> On Tue, 18 Sep 2018 at 12:09, Philip Ó Condúin <
>> philipoconduin@gmail.com> wrote:
>> >>>>
>> >>>> Hi All,
>> >>>>
>> >>>> I need a little advice.  I'm trying to access the JMX terminal using
>> jmxterm-1.0-alpha-4-uber.jar with a very simple default install of C* 3.11.3
>> >>>>
>> >>>> I keep getting the following:
>> >>>>
>> >>>> [cassandra@reaper-1 conf]$ java -jar jmxterm-1.0-alpha-4-uber.jar
>> >>>> Welcome to JMX terminal. Type "help" for available commands.
>> >>>> $>open 1666
>> >>>> #NullPointerException: No such PID 1666
>> >>>> $>
>> >>>>
>> >>>> C* is running with a PID of 1666.  I've tried setting JMX_LOCAL=no
>> and have even created a new VM to test it.
>> >>>>
>> >>>> Does anyone know what I might be doing wrong here?
>> >>>>
>> >>>> Kind Regards,
>> >>>> Phil
>> >>>>
>> >>>
>> >>>
>> >>> --
>> >>> Regards,
>> >>> Phil
>> >>
>> >>
>> >
>> >
>> > --
>> > Regards,
>> > Phil
>>
>
>
> --
> Regards,
> Phil
>

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