apache/cassandra · error · MarshalException

Failure validating the %dth field

Error message

Failure validating the %dth field %s; %s

What it means

MarshalException wrapper from UserTypeSerializer.validate: the nested serializer for the named field rejected the value; the original MarshalException message and cause are chained into a message identifying the offending field index and name. It is a generic delegation guard, not an independent validation.

Solutions

1. Read the chained cause message to find the actual field-level violation
2. Fix the offending field value client-side to conform to its declared type
3. Check that the UDT field type in the schema matches what the client sends

When it happens

Trigger: Thrown at src/java/org/apache/cassandra/serializers/UserTypeSerializer.java:68 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/555b0f2e0a9a2af0. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/serializers/UserTypeSerializer.java:68

            int size = accessor.getInt(input, offset);
            offset += TypeSizes.INT_SIZE;

            // size < 0 means null value
            if (size < 0)
                continue;

            if (accessor.sizeFromOffset(input, offset) < size)
                throw new MarshalException(String.format("Not enough bytes to read %dth field %s", i, entry.getKey()));

            V field = accessor.slice(input, offset, size);
            try
            {
                offset += size;
                entry.getValue().validate(field, accessor);
            }
            catch (MarshalException e)
            {
                throw new MarshalException(String.format("Failure validating the %dth field %s; %s", i, entry.getKey(), e.getMessage()), e);
            }
        }

        // We're allowed to get less fields than declared, but not more
        if (!accessor.isEmptyFromOffset(input, offset))
            throw new MarshalException("Invalid remaining data after end of UDT value");
    }
}

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