apache/cassandra · error · RuntimeException

Bad query to JMX server:

Error message

Bad query to JMX server: 

What it means

RuntimeException wrapper from NodeProbe when querying thread pool MBeans: a MalformedObjectNameException while constructing the ObjectName pattern org.apache.cassandra.metrics:type=ThreadPools,* was caught and rethrown as 'Bad query to JMX server'. Since the pattern is hardcoded, this indicates an environment/registration anomaly rather than user input.

Solutions

1. Retry the nodetool command; the failure is typically transient JMX connectivity related
2. Verify JMX connectivity and that the remote MBean server is responding
3. Check the full chained exception for the malformed name details

When it happens

Trigger: Thrown at src/java/org/apache/cassandra/tools/NodeProbe.java:1993 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/6a2a229c6f9a397c. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/tools/NodeProbe.java:1993

    {
        try
        {
            Multimap<String, String> threadPools = HashMultimap.create();

            Set<ObjectName> threadPoolObjectNames = mbeanServerConn.queryNames(
                    new ObjectName("org.apache.cassandra.metrics:type=ThreadPools,*"),
                    null);

            for (ObjectName oName : threadPoolObjectNames)
            {
                threadPools.put(oName.getKeyProperty("path"), oName.getKeyProperty("scope"));
            }

            return threadPools;
        }
        catch (MalformedObjectNameException e)
        {
            throw new RuntimeException("Bad query to JMX server: ", e);
        }
        catch (IOException e)
        {
            throw new RuntimeException("Error getting threadpool names from JMX", e);
        }
    }

    public Object getThreadPoolMetric(String pathName, String poolName, String metricName)
    {
      String name = String.format("org.apache.cassandra.metrics:type=ThreadPools,path=%s,scope=%s,name=%s",
              pathName, poolName, metricName);

      try
      {
          ObjectName oName = new ObjectName(name);
          if (!mbeanServerConn.isRegistered(oName))
          {
              return "N/A";

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