apache/cassandra · error · IllegalArgumentException

Value of name_size parameter has to be at least %s.

Error message

Value of name_size parameter has to be at least %s.

What it means

Thrown by UUIDRoleNameGenerator.getSize() when the requested name_size is less than the generator-configured minimumNameSize. The requested size parsed fine but is below the configured lower bound for generated names.

Source

Thrown at src/java/org/apache/cassandra/db/guardrails/UUIDRoleNameGenerator.java:185

        if (sizeObject instanceof String)
        {
            try
            {
                size = Integer.parseInt((String) sizeObject);
            }
            catch (Throwable t)
            {
                throw new IllegalArgumentException("Value '" + sizeObject + "' can't be converted to integer.");
            }
        }
        else if (sizeObject instanceof Number)
            size = ((Number) sizeObject).intValue();
        else
            throw new IllegalArgumentException("Unsupported object passed to resolve " + NAME_SIZE + ": " + sizeObject.getClass().getName());

        if (size < minimumNameSize)
            throw new IllegalArgumentException("Value of " + NAME_SIZE + " parameter has to be at least " + minimumNameSize + '.');

        if (size > MAXIMUM_NAME_SIZE)
            throw new IllegalArgumentException("Generator generates names of maximum length " + MAXIMUM_NAME_SIZE + ". " +
                                               "You want to generate with length " + size + '.');

        return size;
    }
}

View on GitHub (pinned to 88fd0f6a0e)

Solutions

1. Raise name_size to at least the configured minimumNameSize
2. Lower the generator's minimum_name_size config option if shorter names are needed (within validateParameters bounds)
3. Catch IllegalArgumentException and retry with a size >= minimumNameSize

Example fix

// before
options.put("name_size", "4"); // generator minimum is 8
// after
options.put("name_size", "8");

int requested = Integer.parseInt((String) options.get("name_size"));
if (requested < generatorMinimumNameSize)
    options.put("name_size", String.valueOf(generatorMinimumNameSize));

boolean withinMinimum(Object v, int minimumNameSize) {
    int n = (v instanceof Number) ? ((Number) v).intValue() : Integer.parseInt((String) v);
    return n >= minimumNameSize;
}

try {
    generator.generate(options);
} catch (IllegalArgumentException e) {
    if (e.getMessage().contains("has to be at least")) {
        // retry with the minimum size stated in the message
    } else throw e;
}

When it happens

Trigger: Calling generate(options) with name_size smaller than the 'minimum_name_size' the generator was configured with (e.g. generator minimum 8, request name_size=4).

Common situations: Callers unaware of the generator's configured minimum; configs where the caller-supplied name_size was tuned for a different generator instance.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

• Generator generates names of maximum length %s. You want to
• MINIMUM_NAME_SIZE_CONFIG_OPTION has to be at least DEFAULT_M
• Value of name_size has to be strictly positive integer.
• Invalid data rate: ${value}. It shouldn't be more than ${max
• Invalid data rate: value must be non-negative

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/185cc0be092d3fcd. Report an issue: GitHub.