pentaho/pentaho-kettle · error · RuntimeException

Row metadata and data: unable to calculate hashcode because…

Error message

Row metadata and data: unable to calculate hashcode because of a data conversion problem

What it means

RowMetaAndData.hashCode() delegates to rowMeta.hashCode(data), which computes a hash from the row's values. A KettleValueException there means a value could not be converted/hashed consistently with its metadata; the method rethrows it as a RuntimeException (hashCode cannot throw checked exceptions).

Solutions

Fix the metadata/data mismatch so each value matches its declared ValueMeta type
Inspect the cause KettleValueException to find the offending field/index
Avoid using rows with custom/unconvertible values as hash keys; compare explicitly with rowMeta.compare instead
Rebuild the row using ValueDataUtil conversions before hashing

Example fix

// before
Set<RowMetaAndData> seen = new HashSet<>();
seen.add(rowMetaAndData); // hashCode() may throw
// after
if (canHash(rowMetaAndData)) {
  seen.add(rowMetaAndData);
} else {
  compareExplicitly(rowMetaAndData, seenRows); // rowMeta.compare based
}

Defensive patterns

Strategy: try-catch

Validate before calling

// pre-validate values are hashable per metadata
for (int i = 0; i < rmad.getRowMeta().size(); i++) {
  try {
    rmad.getRowMeta().getValueMeta(i).getNativeDataType(rmad.getData()[i]);
  } catch (KettleValueException e) {
    throw new IllegalStateException("Unhashable value at index " + i, e);
  }
}

Try / catch

try {
  seen.add(rmad);
} catch (RuntimeException e) {
  // fall back to explicit rowMeta.compare based dedup instead of hashing
}

Prevention

Avoid rows with metadata/value mismatches in hashed collections
Prefer rowMeta.compare for row equality instead of hashCode
Rebuild rows with proper ValueMeta conversions before adding to sets/maps

When it happens

Trigger: Adding a RowMetaAndData to a HashSet/HashMap (triggering hashCode) when a field's value cannot be hashed per its ValueMeta — e.g. incompatible value type, malformed date/binary data, or metadata/data mismatch.

Common situations: Using RowMetaAndData objects as map keys or in sets during row comparison/join logic, rows constructed with wrong types vs declared metadata, custom ValueMeta converters throwing during hashing.

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

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/99583219174bd4db. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/pentaho/di/core/RowMetaAndData.java:107

   */
  public RowMetaInterface getRowMeta() {
    return rowMeta;
  }

  /**
   * @param rowMeta
   *          the rowMeta to set
   */
  public void setRowMeta( RowMetaInterface rowMeta ) {
    this.rowMeta = rowMeta;
  }

  @Override
  public int hashCode() {
    try {
      return rowMeta.hashCode( data );
    } catch ( KettleValueException e ) {
      throw new RuntimeException(
        "Row metadata and data: unable to calculate hashcode because of a data conversion problem", e );
    }
  }

  @Override
  public boolean equals( Object obj ) {
    try {
      return rowMeta.compare( data, ( (RowMetaAndData) obj ).getData() ) == 0;
    } catch ( KettleValueException e ) {
      throw new RuntimeException(
        "Row metadata and data: unable to compare rows because of a data conversion problem", e );
    }
  }

  public void addValue( ValueMetaInterface valueMeta, Object valueData ) {
    if ( valueMeta.isInteger() && ( valueData instanceof ObjectId ) ) {
      valueData = new LongObjectId( (ObjectId) valueData ).longValue();
    }

View on GitHub (pinned to f3058517a1)