apache/beam · error

error decoding single-precision float field

Error message

error decoding single-precision float field

What it means

Wrap added by reflectDecodeSinglePrecisionFloat when DecodeSinglePrecisionFloat fails pulling a 4-byte float from the row byte stream. It signals truncated or corrupt element data for a float32-typed field, or a coder mismatch between producer and consumer.

Solutions

1. Confirm the data source is intact and produced by a compatible encoder.
2. Re-encode the data.
3. Verify reader/writer schemas match field-for-field.
4. Check truncation at the failing offset.

if err := decoderFn(rv, r); err != nil {
    if strings.Contains(err.Error(), "single-precision float") {
        return fmt.Errorf("truncated float32 field in row: %w", err)
    }
    return err
}

When it happens

Trigger: reflectDecodeSinglePrecisionFloat during row decoding when DecodeSinglePrecisionFloat cannot read 4 bytes — truncated input or misaligned decoding.

Common situations: Truncated output files, schema drift changing field layout, decoding data with mismatched coder versions.

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

Related errors

• error decoding bool field
• error decoding double field
• error decoding single byte field
• error decoding string field
• error decoding varint field

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/2e843b6282e409cc. Report an issue: GitHub.

Appendix: source

Thrown at sdks/go/pkg/beam/core/graph/coder/row_decoder.go:247

		return errors.Wrap(err, "error decoding varint field")
	}
	rv.SetInt(v)
	return nil
}

func reflectDecodeUint(rv reflect.Value, r io.Reader) error {
	v, err := DecodeVarUint64(r)
	if err != nil {
		return errors.Wrap(err, "error decoding varint field")
	}
	rv.SetUint(v)
	return nil
}

func reflectDecodeSinglePrecisionFloat(rv reflect.Value, r io.Reader) error {
	v, err := DecodeSinglePrecisionFloat(r)
	if err != nil {
		return errors.Wrap(err, "error decoding single-precision float field")
	}
	rv.SetFloat(float64(v))
	return nil
}

func reflectDecodeFloat(rv reflect.Value, r io.Reader) error {
	v, err := DecodeDouble(r)
	if err != nil {
		return errors.Wrap(err, "error decoding double field")
	}
	rv.SetFloat(v)
	return nil
}

func reflectDecodeByteSlice(rv reflect.Value, r io.Reader) error {
	b, err := DecodeBytes(r)
	if err != nil {
		return errors.Wrap(err, "error decoding []byte field")

View on GitHub (pinned to 12126d8942)