pentaho/pentaho-kettle · error · KettleException

Unexpected error reading step information from the…

Error message

Unexpected error reading step information from the repository

What it means

UniqueRowsByHashSetMeta.readRep loads the step's configuration (compare field names plus settings like reject_duplicate_row) from a repository. Any exception from the repository layer is wrapped in a KettleException with this message, meaning stored step attributes could not be read.

Solutions

Check the cause exception and repository connectivity
Verify the repository schema/version matches your Kettle install
Re-save the step from Spoon to rewrite its attributes
Export to XML and load from file as a workaround

Defensive patterns

Strategy: try-catch

Validate before calling

// Java: confirm repository reachability before reading step attributes
if ( !repository.isConnected() ) {
  throw new IllegalStateException( "Repository not connected before readRep" );
}

Try / catch

try {
  meta.readRep( repository, metaStore, idStep, databases );
} catch ( KettleException e ) {
  logError( "Repository read of UniqueRowsByHashSet step failed: " + e.getCause(), e );
  // re-save step or use XML export
}

Prevention

Check repository connectivity before loads
Sync repository schema with Kettle version
Re-save steps after version upgrades

When it happens

Trigger: readRep (public) fails during rep.getStepAttributeString / attribute count retrieval (e.g. nrfields attribute unreadable, repository connection error) for the Unique rows (HashSet) step.

Common situations: Repository backend unreachable; step attribute rows written by an incompatible Kettle version; corrupt repository data for the step id.

Understand the failure class

Background: Database query failed: Internal Server Error 500s wrapping SQL, Prisma, and connection failures — what to check first — this error's family across 16 libraries.

Related errors

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/d05b4b3811f9377d. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/trans/steps/uniquerowsbyhashset/UniqueRowsByHashSetMeta.java:200

    retval.append( "      </fields>" );

    return retval.toString();
  }

  public void readRep( Repository rep, IMetaStore metaStore, ObjectId id_step, List<DatabaseMeta> databases ) throws KettleException {
    try {
      storeValues = rep.getStepAttributeBoolean( id_step, "store_values" );
      rejectDuplicateRow = rep.getStepAttributeBoolean( id_step, "reject_duplicate_row" );
      errorDescription = rep.getStepAttributeString( id_step, "error_description" );
      int nrfields = rep.countNrStepAttributes( id_step, "field_name" );

      allocate( nrfields );

      for ( int i = 0; i < nrfields; i++ ) {
        compareFields[i] = rep.getStepAttributeString( id_step, i, "field_name" );
      }
    } catch ( Exception e ) {
      throw new KettleException( BaseMessages.getString(
        PKG, "UniqueRowsByHashSetMeta.Exception.UnexpectedErrorReadingStepInfo" ), e );
    }
  }

  public void saveRep( Repository rep, IMetaStore metaStore, ObjectId id_transformation, ObjectId id_step ) throws KettleException {
    try {
      rep.saveStepAttribute( id_transformation, id_step, "store_values", storeValues );
      rep.saveStepAttribute( id_transformation, id_step, "reject_duplicate_row", rejectDuplicateRow );
      rep.saveStepAttribute( id_transformation, id_step, "error_description", errorDescription );
      for ( int i = 0; i < compareFields.length; i++ ) {
        rep.saveStepAttribute( id_transformation, id_step, i, "field_name", compareFields[i] );
      }
    } catch ( KettleException e ) {
      throw new KettleException( BaseMessages.getString(
        PKG, "UniqueRowsByHashSetMeta.Exception.UnableToSaveStepInfo" ), e );
    }
  }

View on GitHub (pinned to f3058517a1)