pentaho/pentaho-kettle · error · KettleException

MultiMergeJoinMeta.Exception.UnexpectedErrorReadingStepInfo

MultiMergeJoinMeta.Exception.UnexpectedErrorReadingStepInfo

Error message

MultiMergeJoinMeta.Exception.UnexpectedErrorReadingStepInfo

What it means

Thrown by MultiMergeJoinMeta.readRep when an unexpected exception occurs while reading the step's configuration from the repository, notably fetching the "join_type" attribute via rep.getStepAttributeString. It wraps the cause in a generic KettleException with this message, indicating step metadata could not be read from the transformation repository tables.

Solutions

Inspect the wrapped cause to identify the repository error (connection vs missing attribute).
Verify repository connectivity and that the transformation and its step rows exist (r_step, r_step_attribute) for the given id_step.
Clear the PDI repository metadata cache (delete the local cache directory) and reload.
Re-save the step from Spoon to rewrite its repository attributes, or recreate the step if attributes are unrecoverable.
Confirm client and repository schema versions are compatible.

Example fix

// before: loading from a repository whose attributes row is gone
TransMeta tm = new TransMeta(repository, "My Trans"); // throws

// after: verify/repair repository state first
if ( repository.getStepAttributeString( idStep, "join_type" ) == null ) {
  // recreate the step or restore r_step_attribute rows, then retry load
}

Defensive patterns

Strategy: try-catch

Validate before calling

// Verify the step's attributes exist in the repository before loading the transformation
String joinType = repository.getStepAttributeString( idStep, "join_type" );
if ( joinType == null ) {
  throw new IllegalStateException( "MultiMergeJoin step " + idStep + " has no join_type attribute; repository data incomplete" );
}

Try / catch

try {
  TransMeta tm = new TransMeta( repository, transName );
} catch ( KettleException e ) {
  if ( e.getMessage().contains( "UnexpectedErrorReadingStepInfo" ) ) {
    // check repository connectivity / id_step rows, clear cache, retry
  } else { throw e; }
}

Prevention

Monitor repository database health and run loads on stable connections.
Back up r_step_attribute data before repository maintenance or restores.
Keep PDI client version compatible with the repository schema.
Clear the local repository cache after server-side changes.

When it happens

Trigger: readRep is called when loading a transformation from a repository; it throws when the repository access layer raises (connection dropped, missing/invalid id_step row, corrupted r_step_attribute entries, repository schema mismatch).

Common situations: Repository database was restored partially so step attributes are missing; stale repository cache after a server-side change; network interruption mid-load; repository schema version differs from the client PDI version.

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/eb0d30809cd8a0fd. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/trans/steps/multimerge/MultiMergeJoinMeta.java:227

      allocateInputSteps( (int) nInputStreams );

      for ( int i = 0; i < nInputStreams; i++ ) {
        inputSteps[i] = rep.getStepAttributeString( id_step, "step" + i );
      }
      // This next bit is completely unnecessary if you just pass the step name into
      // the constructor above. That sets the subject to the step name in one pass
      // instead of a second one.
      // MB - 5/2016
      //
      // List<StreamInterface> infoStreams = getStepIOMeta().getInfoStreams();
      // for ( int i = 0; i < infoStreams.size(); i++ ) {
      //   infoStreams.get( i ).setSubject( rep.getStepAttributeString( id_step, "step" + i ) );
      // }

      joinType = rep.getStepAttributeString( id_step, "join_type" );
    } catch ( Exception e ) {
      throw new KettleException( BaseMessages.getString( PKG,
          "MultiMergeJoinMeta.Exception.UnexpectedErrorReadingStepInfo" ), e );
    }
  }

  @Override
  public void searchInfoAndTargetSteps( List<StepMeta> steps ) {
    StepIOMetaInterface ioMeta = getStepIOMeta();
    ioMeta.getInfoStreams().clear();
    for ( int i = 0; i < inputSteps.length; i++ ) {
      String inputStepName = inputSteps[i];
      if ( i >= ioMeta.getInfoStreams().size() ) {
        ioMeta.addStream(
          new Stream( StreamType.INFO, StepMeta.findStep( steps, inputStepName ),
              BaseMessages.getString( PKG, "MultiMergeJoin.InfoStream.Description" ), StreamIcon.INFO, inputStepName ) );
      }
    }
  }

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