apache/seatunnel · error · UnsupportedOperationException

Unsupported type: ${dataType}

Error message

Unsupported type: ${dataType}

What it means

RowDataToAvroConverters.createConverter maps SeaTunnelRowType SQL type families to Avro row converters; any type outside the handled cases (ROW, MAP, and primitive branches) falls to default and throws UnsupportedOperationException because there is no Avro conversion path for it.

Source

Thrown at seatunnel-connectors-v2/connector-hudi/src/main/java/org/apache/seatunnel/connectors/seatunnel/hudi/sink/convert/RowDataToAvroConverters.java:201

                            @Override
                            public Object convert(Schema schema, Object object) {
                                BigDecimal javaDecimal = (BigDecimal) object;
                                return DECIMAL_CONVERSION.toFixed(
                                        javaDecimal, schema, schema.getLogicalType());
                            }
                        };
                break;
            case ARRAY:
                converter = createArrayConverter((ArrayType<?, ?>) dataType);
                break;
            case ROW:
                converter = createRowConverter((SeaTunnelRowType) dataType);
                break;
            case MAP:
                converter = createMapConverter(dataType);
                break;
            default:
                throw new UnsupportedOperationException("Unsupported type: " + dataType);
        }

        // wrap into nullable converter
        return new RowDataToAvroConverter() {
            private static final long serialVersionUID = 1L;

            @Override
            public Object convert(Schema schema, Object object) {
                if (object == null) {
                    return null;
                }

                // get actual schema if it is a nullable schema
                Schema actualSchema;
                if (schema.getType() == Schema.Type.UNION) {
                    List<Schema> types = schema.getTypes();
                    int size = types.size();
                    if (size == 2 && types.get(1).getType() == Schema.Type.NULL) {

View on GitHub (pinned to cf67b549a7)

Solutions

1. Change the offending column to a supported type via a Cast/SQL transform before the Hudi sink
2. Flatten or convert the unsupported complex type (e.g. MAP<...> to string/JSON) upstream
3. Upgrade SeaTunnel if a newer version added a converter for this type
4. Extend createConverter with a new converter for the type if contributing

Example fix

// before: schema includes ARRAY<MAP<STRING,STRING>> (unsupported)
// after: cast to STRING upstream
SQL transform: SELECT CAST(my_array_col AS STRING) AS my_array_col, ...

// before creating the sink, verify each field type is supported
for (SeaTunnelDataType<?> t : rowType.getFieldTypes()) {
    if (!(t.getSqlType() == SqlType.ROW || t.getSqlType() == SqlType.MAP
        || t.getSqlType() == SqlType.STRING || t.getSqlType() == SqlType.INT
        || t.getSqlType() == SqlType.BOOLEAN /* ...primitives */)) {
        throw new IllegalArgumentException("Unsupported type for Hudi sink: " + t);
    }
}

try {
    sink.write(row);
} catch (UnsupportedOperationException e) {
    LOG.error("Column type not supported by Hudi Avro conversion: {}", e.getMessage());
    // route row to dead-letter or cast upstream and restart
}

When it happens

Trigger: A SeaTunnel schema (SeaTunnelRowType) passed to elementConverter/valueConverter contains a field whose SeaTunnelType has no case in createConverter's switch (e.g. certain array/nested or unsupported complex types).

Common situations: Reading from a source producing exotic types (e.g. specific array element types, bytes variants) and sinking to Hudi; schema evolution adding a new column type; version mismatch between SeaTunnel API types supported by the connector.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Unsupported to derive Schema for type: ${dataType}
• Avro format doesn't support non-string as key type of map. T
• The Avro schema is not a nullable type: ${schema}
• Fail to serialize at field: ${fieldName}.
• COMMON-17

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/d4761925e0fe1d7a. Report an issue: GitHub.