apache/seatunnel · error · IllegalArgumentException

Unsupported FloatingPoint precision:

Error message

Unsupported FloatingPoint precision: 

What it means

FloatingPointTypeWriter.writeToVector maps Arrow FloatingPoint precision to Float4Vector (SINGLE) or Float8Vector (DOUBLE). Arrow defines only HALF/SINGLE/DOUBLE; HALF is not handled, so a HALF precision field reaches the else branch and throws IllegalArgumentException. It means the writer cannot serialize the float value into a vector of that precision.

Source

Thrown at seatunnel-connectors-v2/connector-lance/src/main/java/org/apache/seatunnel/connectors/seatunnel/lance/sink/writers/FloatingPointTypeWriter.java:45

import org.apache.arrow.vector.types.pojo.ArrowType;

/** Writer for FloatingPoint type. */
public class FloatingPointTypeWriter extends BaseTypeWriter {
    @Override
    public void writeToVector(
            FieldVector vector,
            ArrowType arrowType,
            Object value,
            int rowIndex,
            BufferAllocator allocator) {
        ArrowType.FloatingPoint fpType = (ArrowType.FloatingPoint) arrowType;
        Number numValue = (Number) value;
        if (fpType.getPrecision() == FloatingPointPrecision.SINGLE) {
            ((Float4Vector) vector).setSafe(rowIndex, numValue.floatValue());
        } else if (fpType.getPrecision() == FloatingPointPrecision.DOUBLE) {
            ((Float8Vector) vector).setSafe(rowIndex, numValue.doubleValue());
        } else {
            throw new IllegalArgumentException(
                    "Unsupported FloatingPoint precision: " + fpType.getPrecision());
        }
    }

    @Override
    public void writeToListWriter(
            UnionListWriter writer, ArrowType arrowType, Object value, BufferAllocator allocator) {
        ArrowType.FloatingPoint fpType = (ArrowType.FloatingPoint) arrowType;
        Number numValue = (Number) value;
        if (fpType.getPrecision() == FloatingPointPrecision.SINGLE) {
            writer.writeFloat4(numValue.floatValue());
        } else if (fpType.getPrecision() == FloatingPointPrecision.DOUBLE) {
            writer.writeFloat8(numValue.doubleValue());
        }
    }

    @Override
    public void writeToMapKey(

View on GitHub (pinned to cf67b549a7)

Solutions

1. Change the target column to SINGLE (float4) or DOUBLE (float8) precision, recreating the dataset if needed.
2. Cast half-float values to float in the upstream transform before the sink.
3. Upgrade the connector if Float16 support is added in a newer version.

Example fix

// before
new ArrowType.FloatingPoint(FloatingPointPrecision.HALF)
// after
new ArrowType.FloatingPoint(FloatingPointPrecision.SINGLE)

ArrowType t = field.getType(); if (t instanceof ArrowType.FloatingPoint && ((ArrowType.FloatingPoint) t).getPrecision() == FloatingPointPrecision.HALF) throw new IllegalArgumentException("HALF float not supported by lance sink");

try { writer.write(row); } catch (IllegalArgumentException e) { if (e.getMessage().startsWith("Unsupported FloatingPoint precision")) { /* recast column to SINGLE/DOUBLE */ } throw e; }

When it happens

Trigger: A field's ArrowType is FloatingPoint with precision HALF (Float16) and writeToVector is called for it.

Common situations: Dataset schema created externally with half-float columns (common in ML/embedding data stored in Lance) being written by this SeaTunnel connector, which lacks Float16 support.

Related errors

• List type should be handled via FragmentConverter.writeListT
• Nested list writing not yet implemented
• TABLE_DATASET_WRITE_ST_ROW_EXCEPTION
• Unsupported timestamp value type:
• Unsupported Date unit:

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/4ee498adb97a9e3f. Report an issue: GitHub.