apache/cassandra · error · RuntimeException

Error getting threadpool names from JMX

Error message

Error getting threadpool names from JMX

What it means

RuntimeException wrapper from NodeProbe.getThreadPoolNames when the IOException from the remote MBean server connection (queryNames) is caught and rethrown. This is a transport-level failure talking to JMX, not a data problem.

Solutions

1. Check JMX connectivity (host, port, credentials) used by nodetool
2. Confirm the remote node is up and its JMX service is healthy
3. Retry after network issues are resolved

When it happens

Trigger: Thrown at src/java/org/apache/cassandra/tools/NodeProbe.java:1997 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/1a6c19136e9a6c34. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/tools/NodeProbe.java:1997

            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";
          }

          switch (metricName)
          {

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