apache/cassandra · error · ConfigurationException

Memtable class ${className} does not accept any futher param

Error message

Memtable class ${className} does not accept any futher parameters, but ${parametersCopy} were given.

What it means

Thrown from MemtableParams.getMemtableFactory after reflective loading of a custom memtable class: the resolved Memtable.Factory does not accept further parameters, but the configuration entry still has leftover option keys after consuming recognized ones. Cassandra treats unconsumed parameters as invalid configuration and throws a ConfigurationException (the message contains a pre-existing typo 'futher').

Source

Thrown at src/java/org/apache/cassandra/schema/MemtableParams.java:253

            try
            {
                Method factoryMethod = clazz.getDeclaredMethod("factory", Map.class);
                if (!Memtable.Factory.class.isAssignableFrom(factoryMethod.getReturnType()))
                    throw new ClassCastException("Memtable factory method on " + className +
                                                 " must return " + Memtable.Factory.class.getName());
                factory = (Memtable.Factory) factoryMethod.invoke(null, parametersCopy);
            }
            catch (NoSuchMethodException e)
            {
                // continue with FACTORY field
                Field factoryField = clazz.getDeclaredField("FACTORY");
                if (!Memtable.Factory.class.isAssignableFrom(factoryField.getType()))
                    throw new ClassCastException("Memtable FACTORY field on " + className +
                                                 " must be of type " + Memtable.Factory.class.getName());
                factory = (Memtable.Factory) factoryField.get(null);
            }
            if (!parametersCopy.isEmpty())
                throw new ConfigurationException("Memtable class " + className + " does not accept any futher parameters, but " +
                                                 parametersCopy + " were given.");
            return factory;
        }
        catch (NoSuchFieldException | ClassNotFoundException | IllegalAccessException | InvocationTargetException | ClassCastException e)
        {
            if (e.getCause() instanceof ConfigurationException)
                throw (ConfigurationException) e.getCause();
            throw new ConfigurationException("Could not create memtable factory for class " + options, e);
        }
    }
}

View on GitHub (pinned to 88fd0f6a0e)

Solutions

Remove unsupported parameters from the entry in cassandra.yaml, leaving only class_name (plus params the memtable actually supports).
Switch class_name to a memtable implementation that supports the parameters you need.
Fix parameter key spelling so the factory recognizes and consumes them.
Check the memtable class's accepted parameter list in its documentation/source.

Example fix

# before (cassandra.yaml)
memtable_configurations:
  plain:
    class_name: SkipListMemtable
    shards: 4
# after
memtable_configurations:
  plain:
    class_name: SkipListMemtable

Defensive patterns

Strategy: validation

Validate before calling

// pre-check: only pass parameters documented by the target memtable class
Map<String,String> params = new HashMap<>(options); params.remove("class_name");
if (!targetMemtableAcceptsParams(className) && !params.isEmpty()) throw new IllegalStateException(className + " accepts no parameters; remove " + params.keySet());

Try / catch

try { parseMemtableConfig(entry); } catch (ConfigurationException e) { if (e.getMessage().contains("does not accept any")) stripUnknownParamsAndRetry(); else throw e; }

Prevention

Only supply parameters explicitly supported by the memtable class's factory.
Read the target memtable class's source/docs for its accepted parameter names before configuring.
Do not copy OPTIONS blocks between different memtable implementations.
Watch for typos: an unconsumed key surfaces as this error, not as 'unknown option'.

When it happens

Trigger: memtable_configurations entry with class_name pointing at a memtable whose FACTORY field rejects parameters (e.g. SkipListMemtable which takes none) while the entry supplies options like {'class_name':'SkipListMemtable','some_param':'1'}; after factory extraction, parametersCopy is non-empty.

Common situations: Passing options like 'shards' to a memtable class that doesn't support them, copy-pasting options between SkipListMemtable and configurable memtable implementations, misspelling a supported parameter name so it isn't consumed.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/01ed9eef0bafb043. Report an issue: GitHub.