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Taking Thread dumps to Troubleshoot High CPU Utilization

Created: 2012-11-08 18:07:47 UTC
Last Update: 2017-10-05 14:04:57 UTC



  • Avatar
    Philip Southam

    To save you some time, If you're using a modern version of java you probably won't have the jstack utility (as it appears to be depricated and will have to use the script.

  • Avatar
    J.B. Langston

    jstack is only included in the JDK, not the JRE. It is still available as of JDK 7, which is the version that Cassandra currently supports.

  • Avatar
    Philip Southam

    I stand corrected, thanks J.B.

  • Avatar
    José Martínez Poblete

    Attached a version of the script which merges the original scripts

    Usage: ./ -i <interval> -c <count> -pid <PID> -pgm [jstack|kill]

           Default interval: 5 secs

           Default count   : 60

           Default PID     : DSE java PID

           Default PGM     : jstack


  • Avatar
    José Martínez Poblete

    I have changed the code of the script in order to get the information we need

    Attached is a newer version of the script. It needs the following in order to run

    On /etc/password make sure the cassandra user is set to use /bin/bash rather than /bin/false

    cassandra:x:106:111:Cassandra database,,,:/var/lib/cassandra:/bin/bash

    We need to use Oracle jstack, it will use the command resulting from this search:

    find /usr -name jstack -type f -perm /a=x | egrep -v openjdk | tail -1

    Become root and then cassandra, then execute:


    A succesful execution would look like this

    automaton@ip-172-31-2-39:~$ ./
    Begin processing...
    PID   %CPU  Process
    ===== ===== =======
    27825 8.15 MemoryMeter:1
     6930 7.00 CompactionExecutor:25
     6929 6.50 FlushWriter:13
    27063 5.90 Gang worker#0 (Parallel GC Threads)
    27064 5.90 Gang worker#1 (Parallel GC Threads)
    27828 5.50 COMMIT-LOG-WRITER
    Collecting files...
    End processing, please collect /tmp/multidump.tgz



  • Avatar
    Michael Keeney

    We've also run in to several instances of this error:

    Unable to open socket file: target process not responding or HotSpot VM not loaded
    The -F option can be used when the target process is not responding

    The following fixed it (along with editing to include):

    sudo -u cassandra jstack -J-d64 -l <PID> >> jstack.out

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