pentaho/pentaho-kettle · error · KettleException

MergeJoinMeta.Exception.UnexpectedErrorReadingStepInfo

MergeJoinMeta.Exception.UnexpectedErrorReadingStepInfo

Error message

MergeJoinMeta.Exception.UnexpectedErrorReadingStepInfo

What it means

Thrown by MergeJoinMeta.readRep when loading the Merge Join step definition from the Kettle repository fails with an unexpected Exception. It reads step1, step2 and join_type step attributes for the given id_step and wraps any failure in a KettleException with this message.

Solutions

1. Check the wrapped cause (KettleException.getCause()) for the underlying repository error.
2. Verify repository connectivity (database up, credentials valid) and retry loading the transformation.
3. Query R_STEP_ATTRIBUTE for the id_step to confirm step1/step2/join_type rows exist; re-save the step in Spoon to recreate them.
4. If the repository schema is inconsistent, run the repository upgrade/repair tooling for your Kettle version.

// Verify the step's attributes exist in the repository before load
// SELECT COUNT(*) FROM R_STEP_ATTRIBUTE WHERE ID_STEP = ?  -- expect > 0

try {
  TransMeta tm = new TransMeta(repository, transName, directory);
} catch (KettleException e) {
  log.error("Repository read failed for merge join step: " + e.getCause(), e);
}

When it happens

Trigger: Calling readRep (via TransMeta loading from a repository) when the repository query for step attributes of id_step throws — e.g. missing rows in R_STEP_ATTRIBUTE, repository connection failures, or a corrupted step record.

Common situations: Loading a transformation from a repository where its step attribute rows were deleted or never saved; database connectivity problems mid-load; repository schema version mismatch.

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

• AccessInputMeta.Exception.ErrorReadingRepository
• AggregateRowsMeta.Exception.UnexpectedErrorWhileReadingStepInfo
• AggregateRowsMeta.Exception.UnableToSaveStepInfo
• CubeInputMeta.Exception.UnableToSaveStepInfo
• CubeOutputMeta.Exception.UnableToSaveStepInfo

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/8433a219598f74de. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/trans/steps/mergejoin/MergeJoinMeta.java:236

    try {
      int nrKeys1 = rep.countNrStepAttributes( id_step, "keys_1" );
      int nrKeys2 = rep.countNrStepAttributes( id_step, "keys_2" );

      allocate( nrKeys1, nrKeys2 );

      for ( int i = 0; i < nrKeys1; i++ ) {
        keyFields1[i] = rep.getStepAttributeString( id_step, i, "keys_1" );
      }
      for ( int i = 0; i < nrKeys2; i++ ) {
        keyFields2[i] = rep.getStepAttributeString( id_step, i, "keys_2" );
      }

      List<StreamInterface> infoStreams = getStepIOMeta().getInfoStreams();
      infoStreams.get( 0 ).setSubject( rep.getStepAttributeString( id_step, "step1" ) );
      infoStreams.get( 1 ).setSubject( rep.getStepAttributeString( id_step, "step2" ) );
      joinType = rep.getStepAttributeString( id_step, "join_type" );
    } catch ( Exception e ) {
      throw new KettleException( BaseMessages.getString(
        PKG, "MergeJoinMeta.Exception.UnexpectedErrorReadingStepInfo" ), e );
    }
  }

  @Override
  public void searchInfoAndTargetSteps( List<StepMeta> steps ) {
    List<StreamInterface> infoStreams = getStepIOMeta().getInfoStreams();
    for ( StreamInterface stream : infoStreams ) {
      stream.setStepMeta( StepMeta.findStep( steps, (String) stream.getSubject() ) );
    }
  }

  public void saveRep( Repository rep, IMetaStore metaStore, ObjectId id_transformation, ObjectId id_step ) throws KettleException {
    try {
      for ( int i = 0; i < keyFields1.length; i++ ) {
        rep.saveStepAttribute( id_transformation, id_step, i, "keys_1", keyFields1[i] );
      }

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