{"type":"doc","content":[{"type":"paragraph","content":[{"text":"A thread dump gives insights into the state of a Java application ","type":"text"},{"text":"at one point in time","type":"text","marks":[{"type":"em"}]},{"text":". It provides an overview of all active threads for the moment the snapshot is taken.","type":"text"}]},{"type":"paragraph","content":[{"text":"To be more useful for analysis and give a better representation of what is going on within an application it is common to create multiple of these snapshots at regular intervals. Ten dumps, one every 10 seconds could be an example of such a scheme.","type":"text"}]},{"type":"heading","attrs":{"level":2},"content":[{"text":"Instructions","type":"text"}]},{"type":"paragraph","content":[{"text":"On a virtual machine","type":"text","marks":[{"type":"strong"}]}]},{"type":"orderedList","attrs":{"order":1},"content":[{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Create a run script called ","type":"text"},{"text":"jStackSeries.sh","type":"text","marks":[{"type":"em"}]},{"text":" that looks as follows on your HiveMQ machine","type":"text"},{"type":"hardBreak"}]},{"type":"codeBlock","attrs":{"language":"shell"},"content":[{"text":"#!/bin/bash\nif [ $# -eq 0 ]; then\n echo >&2 \"Usage: jstackSeries [ [ ] ]\"\n echo >&2 \" Defaults: count = 10, delay = 0.5 (seconds)\"\n exit 1\nfi\npid=$1 # required\nuser=$2 # required\ncount=${3:-10} # defaults to 10 times\ndelay=${4:-0.5} # defaults to 0.5 seconds\nwhile [ $count -gt 0 ]\ndo\n sudo -u $user jstack -l $pid >jstack.$pid.$(date +%H%M%S.%N)\n sleep $delay\n let count--\n echo -n \".\"\ndone","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Find the HiveMQ run user and process ID by running ","type":"text"},{"text":"ps aux | grep hivemq","type":"text","marks":[{"type":"code"}]}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Run the script as follows:","type":"text"},{"type":"hardBreak"},{"text":"sh jStackSeries-docker.sh 20","type":"text","marks":[{"type":"code"}]}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"This will result in 20 files (filename: 'jstack...N') being generated","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Please pack these 20 files in a zip file and attach them to your HiveMQ Support issue","type":"text"}]}]}]},{"type":"paragraph","content":[{"text":" In docker","type":"text","marks":[{"type":"strong"}]}]},{"type":"orderedList","attrs":{"order":1},"content":[{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Create the following run run-script ","type":"text"},{"text":"jstack-series.sh","type":"text","marks":[{"type":"em"}]},{"type":"hardBreak"}]},{"type":"codeBlock","attrs":{"language":"shell"},"content":[{"text":"#!/bin/bash\nif [ $# -eq 0 ]; then\n echo >&2 \"Usage: jstackSeries [ [ ] ]\"\n echo >&2 \" Defaults: count = 10, delay = 0.5 (seconds)\"\n exit 1\nfi\ncount=${1:-20} # defaults to 10 times\ndelay=${2:-0.5} # defaults to 0.5 seconds\nwhile [ $count -gt 0 ]\ndo\n ./jattach 1 threaddump>jstack.$pid.$(date +%H%M%S.%N)\n sleep $delay\n let count--\n echo -n \".\"\ndone","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Run the following inside your Docker container:","type":"text"},{"type":"hardBreak"}]},{"type":"codeBlock","attrs":{"language":"shell"},"content":[{"text":"curl -L https://github.com/apangin/jattach/releases/download/v2.0/jattach > jattach && \\\nchmod +x jattach","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Run the created script:","type":"text"},{"text":" ./jstack-series.sh","type":"text","marks":[{"type":"code"}]}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"This will result in 20 files (filename: 'jstack...N') being generated","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Please pack these 20 files in a zip file and attach them to your HiveMQ Support issue","type":"text"}]}]}]},{"type":"panel","attrs":{"panelType":"info"},"content":[{"type":"paragraph","content":[{"text":"Make sure that you run the script with user that has the necessary permissions. (i.e. root or the HiveMQ run user) ","type":"text"}]}]}],"version":1}

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