apache/hadoop · error · HadoopIllegalArgumentException

Invalid numDataUnits and numParityUnits

Error message

Invalid numDataUnits and numParityUnits

What it means

Error "Invalid numDataUnits and numParityUnits" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/erasurecode/rawcoder/RSLegacyRawDecoder.java:46

/**
 * A raw erasure decoder in RS code scheme in pure Java in case native one
 * isn't available in some environment. Please always use native implementations
 * when possible.
 *
 * Currently this implementation will compute and decode not to read units
 * unnecessarily due to the underlying implementation limit in GF. This will be
 * addressed in HADOOP-11871.
 */
@InterfaceAudience.Private
public class RSLegacyRawDecoder extends RawErasureDecoder {
  // To describe and calculate the needed Vandermonde matrix
  private int[] errSignature;
  private int[] primitivePower;

  public RSLegacyRawDecoder(ErasureCoderOptions coderOptions) {
    super(coderOptions);
    if (getNumAllUnits() >= RSUtil.GF.getFieldSize()) {
      throw new HadoopIllegalArgumentException(
              "Invalid numDataUnits and numParityUnits");
    }

    this.errSignature = new int[getNumParityUnits()];
    this.primitivePower = RSUtil.getPrimitivePower(getNumDataUnits(),
        getNumParityUnits());
  }

  @Override
  public void decode(ByteBuffer[] inputs, int[] erasedIndexes,
                     ByteBuffer[] outputs) throws IOException {
    // Make copies avoiding affecting original ones;
    ByteBuffer[] newInputs = new ByteBuffer[inputs.length];
    int[] newErasedIndexes = new int[erasedIndexes.length];
    ByteBuffer[] newOutputs = new ByteBuffer[outputs.length];

    // Adjust the order to match with underlying requirements.
    adjustOrder(inputs, newInputs,

View on GitHub (pinned to 2add963021)

Solutions

1. Use valid RS legacy parameters (e.g. 6 data + 3 parity units); check the codec configuration for unsupported unit counts.

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/erasurecode/rawcoder/RSLegacyRawDecoder.java:46 when the library encounters an invalid state.

Common situations: Occurs when RSLegacyRawDecoder is created with invalid numDataUnits/numParityUnits values. Use supported values (e.g., 6+3) for the legacy RS codec.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/95aff2d06c566718. Report an issue: GitHub.