pentaho/pentaho-kettle · error · KettleValueException

The 'combination2' function only works on numeric data

Error message

The 'combination2' function only works on numeric data

What it means

The 'combination2' helper computes SQRT(A*A + B*B) and handles only numeric value types (Number, Integer, BigNumber). Any other metadata type for A reaches the default branch and throws this KettleValueException. It exists because hypotenuse-style math is only defined on numeric data.

Solutions

1. Ensure fields A and B are typed Number/Integer/BigNumber in the Calculator step (fix metadata in a preceding Select Values step).
2. Convert string inputs to numbers before the Calculator step.
3. Wrap the calculation in a UDJC/UDJE step that validates ValueMetaInterface.getType() first.

Example fix

// before: Calculator combination2 fed fieldA as String
// after: Select Values step: fieldA -> Type: Number; then combination2(A=fieldA, B=fieldB)

if (!isNumericMeta(metaA) || !isNumericMeta(metaB)) {
  throw new KettleValueException("combination2 (SQRT(A*A+B*B)) requires numeric A and B");
}

public static boolean isNumericMeta(ValueMetaInterface m) {
  int t = m.getType();
  return t == ValueMetaInterface.TYPE_NUMBER || t == ValueMetaInterface.TYPE_INTEGER || t == ValueMetaInterface.TYPE_BIGNUMBER;
}

try {
  result = ValueDataUtil.combination2(metaA, dataA, metaB, dataB);
} catch (KettleValueException e) {
  logError("combination2 requires numeric fields: " + e.getMessage());
  result = null; // or send row to error stream
}

When it happens

Trigger: Calling ValueDataUtil.combination2 (Calculator type 'SQRT( A*A + B*B )') where metaA.getType() is not TYPE_NUMBER, TYPE_INTEGER, or TYPE_BIGNUMBER — e.g. String or Date input fields.

Common situations: Calculator step receiving string fields from a text file input without conversion; upstream step changed a field's type; user connected a timestamp field into the combination2 calculation.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• The 'abs' function only works on numeric data
• The 'ceil' function only works on numeric data
• The 'combination1' function only works on numeric data
• The 'floor' function only works on numeric data
• The 'remainder' function only works on numeric data

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/1a0e350d97929ce1. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/pentaho/di/core/row/ValueDataUtil.java:1178

    switch ( metaA.getType() ) {
      case ValueMetaInterface.TYPE_NUMBER:
        return new Double( Math.sqrt( metaA.getNumber( dataA ).doubleValue()
          * metaA.getNumber( dataA ).doubleValue() + metaB.getNumber( dataB ).doubleValue()
          * metaB.getNumber( dataB ).doubleValue() ) );

      case ValueMetaInterface.TYPE_INTEGER:
        return new Long( Math.round( Math.sqrt( metaA.getInteger( dataA ).longValue()
          * metaA.getInteger( dataA ).longValue() + metaB.getInteger( dataB ).longValue()
          * metaB.getInteger( dataB ).longValue() ) ) );

      case ValueMetaInterface.TYPE_BIGNUMBER:
        return BigDecimal.valueOf( Math.sqrt( metaA.getNumber( dataA ).doubleValue()
          * metaA.getNumber( dataA ).doubleValue() + metaB.getNumber( dataB ).doubleValue()
          * metaB.getNumber( dataB ).doubleValue() ) );

      default:
        throw new KettleValueException( "The 'combination2' function only works on numeric data" );
    }
  }

  /**
   * Rounding with no decimal places (using default rounding method ROUND_HALF_CEILING)
   *
   * @param metaA
   *          Metadata of value to round
   * @param dataA
   *          Value to round
   * @return The rounded value
   * @throws KettleValueException
   */
  public static Object round( ValueMetaInterface metaA, Object dataA ) throws KettleValueException {
    if ( dataA == null ) {
      return null;
    }

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