apache/hadoop · error · HadoopIllegalArgumentException

Invalid getNumDataUnits() and numParityUnits

Error message

Invalid getNumDataUnits() and numParityUnits

What it means

Error "Invalid getNumDataUnits() and numParityUnits" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/erasurecode/rawcoder/RSRawDecoder.java:61

   * decode calls.
   */
  private byte[] decodeMatrix;
  private byte[] invertMatrix;
  /**
   * Array of input tables generated from coding coefficients previously.
   * Must be of size 32*k*rows
   */
  private byte[] gfTables;
  private int[] cachedErasedIndexes;
  private int[] validIndexes;
  private boolean[] erasureFlags;

  public RSRawDecoder(ErasureCoderOptions coderOptions) {
    super(coderOptions);

    int numAllUnits = getNumAllUnits();
    if (getNumAllUnits() >= RSUtil.GF.getFieldSize()) {
      throw new HadoopIllegalArgumentException(
              "Invalid getNumDataUnits() and numParityUnits");
    }

    encodeMatrix = new byte[numAllUnits * getNumDataUnits()];
    RSUtil.genCauchyMatrix(encodeMatrix, numAllUnits, getNumDataUnits());
    if (allowVerboseDump()) {
      DumpUtil.dumpMatrix(encodeMatrix, getNumDataUnits(), numAllUnits);
    }
  }

  @Override
  protected void doDecode(ByteBufferDecodingState decodingState) {
    CoderUtil.resetOutputBuffers(decodingState.outputs,
        decodingState.decodeLength);
    prepareDecoding(decodingState.inputs, decodingState.erasedIndexes);

    ByteBuffer[] realInputs = new ByteBuffer[getNumDataUnits()];
    for (int i = 0; i < getNumDataUnits(); i++) {

View on GitHub (pinned to 2add963021)

Solutions

1. Check the RS codec configuration; numDataUnits and numParityUnits must be within the supported range (e.g. 6+3) and consistent with the schema.

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/erasurecode/rawcoder/RSRawDecoder.java:61 when the library encounters an invalid state.

Common situations: Occurs when RSRawDecoder is created with invalid numDataUnits/numParityUnits values. Configure valid RS codec unit counts (e.g., 6 data, 3 parity).

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/d3b5a992868bcd95. Report an issue: GitHub.