apache/flink · error · PbCodegenException

Do not support flink type:

Error message

Do not support flink type: 

What it means

During protobuf codegen for deserialization, the factory dispatches on the Flink LogicalType: RowType, simple types, ArrayType, and MapType are handled; anything else falls through to this PbCodegenException. In practice this means the table schema contains a type the protobuf format cannot map, such as RAW, DISTINCT_TYPE, STRUCTURED_TYPE, or a unsupported root type on a non-proto field path.

Source

Thrown at flink-formats/flink-protobuf/src/main/java/org/apache/flink/formats/protobuf/deserialize/PbCodegenDeserializeFactory.java:48

/** Codegen factory class which return {@link PbCodegenDeserializer} of different data type. */
public class PbCodegenDeserializeFactory {
    public static PbCodegenDeserializer getPbCodegenDes(
            Descriptors.FieldDescriptor fd, LogicalType type, PbFormatContext formatContext)
            throws PbCodegenException {
        // We do not use FieldDescriptor to check because there's no way to get
        // element field descriptor of array type.
        if (type instanceof RowType) {
            return new PbCodegenRowDeserializer(fd.getMessageType(), (RowType) type, formatContext);
        } else if (PbFormatUtils.isSimpleType(type)) {
            return new PbCodegenSimpleDeserializer(fd, type);
        } else if (type instanceof ArrayType) {
            return new PbCodegenArrayDeserializer(
                    fd, ((ArrayType) type).getElementType(), formatContext);
        } else if (type instanceof MapType) {
            return new PbCodegenMapDeserializer(fd, (MapType) type, formatContext);
        } else {
            throw new PbCodegenException("Do not support flink type: " + type);
        }
    }

    public static PbCodegenDeserializer getPbCodegenTopRowDes(
            Descriptors.Descriptor descriptor, RowType rowType, PbFormatContext formatContext) {
        return new PbCodegenRowDeserializer(descriptor, rowType, formatContext);
    }
}

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Read the exception message: it prints the exact offending LogicalType — locate that column in the DDL.
2. Remove or cast the unsupported column (RAW/MULTISET/structured) to a supported type (INT, BIGINT, STRING/VARCHAR, BOOLEAN, FLOAT, DOUBLE, BYTES/VARBINARY, DECIMAL, DATE, TIME, TIMESTAMP, ROW, ARRAY, MAP).
3. Re-run CREATE TABLE and verify schema validation passes before submitting the job.

Example fix

-- before
CREATE TABLE pb (
  id BIGINT,
  payload RAW
) WITH ('format'='protobuf', ...);
-- after
CREATE TABLE pb (
  id BIGINT,
  payload BYTES
) WITH ('format'='protobuf', ...);

static boolean pbSupports(LogicalType t) {
    return t instanceof RowType
            || t instanceof ArrayType
            || t instanceof MapType
            || PbFormatUtils.isSimpleType(t);
}
rowType.getFields().forEach(f -> {
    if (!pbSupports(f.getType())) throw new IllegalArgumentException("Unsupported: " + f.getName());
});

boolean isPbMappable(LogicalType t) {
    return t instanceof RowType || t instanceof ArrayType || t instanceof MapType
            || PbFormatUtils.isSimpleType(t);
}

When it happens

Trigger: A table column typed RAW('...', ...) / MULTISET / structured type used with format='protobuf'; a column whose LogicalType root is not in PbFormatUtils.isSimpleType and not row/array/map.

Common situations: Protobuf tables derived from wide catalogs where a helper column (raw type, multiset) was left in the DDL; using types valid in SQL but not representable in proto3.

Related errors

• Illegal type for protobuf enum, only char/vachar/int/bigint
• Do not support flink data type:
• Unsupported data type in schema:
• Unsupported data type in schema:
• Unsupported Avro type '%s'.

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/45adefccd050110d. Report an issue: GitHub.