apache/cassandra · error · MarshalException

Not enough bytes to read %dth field

Error message

Not enough bytes to read %dth field %s

What it means

Thrown during UDT value deserialization when the serialized buffer runs out of bytes before the i-th declared field can be read (fewer than 4 bytes for its size prefix, or an empty buffer for remaining fields). Fires on corrupt or truncated UDT payloads; having fewer fields than declared is otherwise tolerated.

Solutions

1. Verify each field's serialized length matches the written size prefix
2. Re-serialize with the correct UDT type; check writer/reader type-definition drift
3. Inspect the payload for corruption

When it happens

Trigger: Thrown at src/java/org/apache/cassandra/serializers/UserTypeSerializer.java:58 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/9c3a024c9999e72e. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/serializers/UserTypeSerializer.java:58

        for (Entry<String, TypeSerializer<?>> entry : fields.entrySet())
        {
            i++;
            // we allow the input to have less fields than declared so as to support field addition.
            if (accessor.isEmptyFromOffset(input, offset))
                return;

            if (accessor.sizeFromOffset(input, offset) < 4)
                throw new MarshalException(String.format("Not enough bytes to read size of %dth field %s", i, entry.getKey()));

            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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