apache/seatunnel · error · ClickhouseConnectorException

UNSUPPORTED_DATA_TYPE

UNSUPPORTED_DATA_TYPE

Error message

data type in array is not supported: {}

What it means

TypeConvertUtil.convert maps ClickHouse column types to SeaTunnel types; when the column is an array whose element type is not one of the supported primitives (INT, LONG, FLOAT, DOUBLE, SHORT, BOOLEAN, BYTE), it throws UNSUPPORTED_DATA_TYPE. Arrays of strings, decimals, dates, or nested arrays are not convertible by this utility.

Source

Thrown at seatunnel-connectors-v2/connector-clickhouse/src/main/java/org/apache/seatunnel/connectors/seatunnel/clickhouse/util/TypeConvertUtil.java:64

            SeaTunnelDataType<?> dataType = convert(subArrayDataType);
            if (BasicType.INT_TYPE.equals(dataType)) {
                return ArrayType.INT_ARRAY_TYPE;
            } else if (BasicType.STRING_TYPE.equals(dataType)) {
                return ArrayType.STRING_ARRAY_TYPE;
            } else if (BasicType.FLOAT_TYPE.equals(dataType)) {
                return ArrayType.FLOAT_ARRAY_TYPE;
            } else if (BasicType.DOUBLE_TYPE.equals(dataType)) {
                return ArrayType.DOUBLE_ARRAY_TYPE;
            } else if (BasicType.LONG_TYPE.equals(dataType)) {
                return ArrayType.LONG_ARRAY_TYPE;
            } else if (BasicType.SHORT_TYPE.equals(dataType)) {
                return ArrayType.SHORT_ARRAY_TYPE;
            } else if (BasicType.BOOLEAN_TYPE.equals(dataType)) {
                return ArrayType.BOOLEAN_ARRAY_TYPE;
            } else if (BasicType.BYTE_TYPE.equals(dataType)) {
                return ArrayType.BYTE_ARRAY_TYPE;
            } else {
                throw new ClickhouseConnectorException(
                        CommonErrorCodeDeprecated.UNSUPPORTED_DATA_TYPE,
                        "data type in array is not supported: " + subArrayDataType.getDataType());
            }
        }
        Class<?> type = column.getDataType().getObjectClass();
        if (Integer.class.equals(type)) {
            return BasicType.INT_TYPE;
        } else if (Long.class.equals(type)) {
            return BasicType.LONG_TYPE;
        } else if (Short.class.equals(type)) {
            return BasicType.SHORT_TYPE;
        } else if (Byte.class.equals(type)) {
            return BasicType.BYTE_TYPE;
        } else if (Boolean.class.equals(type)) {
            return BasicType.BOOLEAN_TYPE;
        } else if (LocalDate.class.equals(type)) {
            return LocalTimeType.LOCAL_DATE_TYPE;
        } else if (LocalDateTime.class.equals(type)) {

View on GitHub (pinned to cf67b549a7)

Solutions

1. Exclude the unsupported array column from the read schema (select only supported columns).
2. Cast the column to a supported type in ClickHouse (e.g. materialize Array(String) via arrayJoin or read as a single string) or change the table schema.
3. Upgrade SeaTunnel to a version whose TypeConvertUtil supports the element type (String arrays and more were added in later releases).
4. Implement a custom conversion by extending the connector if the data is essential.

Example fix

// before
schema = { columns = { tags = "array<string>" } }  // Array(String) unsupported here
// after
schema = { columns = { tags_joined = "string" } }  // read arrayToString(tags) or drop the column

// ensure every array column's element type is a supported primitive before reading
schema.getColumns().forEach(col -> {
    if (isClickhouseArray(col) && !SUPPORTED_ELEMENT_TYPES.contains(elementTypeOf(col))) {
        throw new IllegalArgumentException("unsupported array element: " + col);
    }
});

try {
    SeaTunnelDataType<?> t = TypeConvertUtil.convert(column);
} catch (ClickhouseConnectorException e) {
    LOG.warn("skipping column with unsupported array element type");
    columns.remove(column); // fallback: drop the column
}

When it happens

Trigger: Reading a ClickHouse column like Array(String), Array(Decimal), Array(Date), or Array(Array(Int)) where the element type has no BasicType mapping in TypeConvertUtil.convert.

Common situations: ClickHouse tables using Array(String) — very common — being read with this connector version; nested array columns; schema discovered from the table includes an array column the reader can't map.

Related errors

• array inject error, unsupported data type: " + type
• COMMON-19
• Unsupported type in LocalTimeArrayType: ${eleSqlType}
• UNSUPPORTED_DATA_TYPE
• Unsupported SQL type:

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/ba1f31587d2997e7. Report an issue: GitHub.