{"record":{"id":"9125ba76c255cec1","repo":"pentaho/pentaho-kettle","slug":"mappingoutput-exception-unabletoconnectwithparentmapping","errorCode":"MappingOutput.Exception.UnableToConnectWithParentMapping","errorMessage":"MappingOutput.Exception.UnableToConnectWithParentMapping","messagePattern":"MappingOutput\\.Exception\\.UnableToConnectWithParentMapping","errorType":"exception","errorClass":"KettleException","httpStatus":null,"severity":"error","filePath":"engine/src/main/java/org/pentaho/di/trans/steps/mappingoutput/MappingOutput.java","lineNumber":83,"sourceCode":"      meta.setInputValueRenames( data.inputValueRenames );\n      meta.getFields( getTransMeta().getBowl(), data.outputRowMeta, getStepname(), null, null, this, repository,\n        metaStore );\n\n      //\n      // Wait until the parent transformation has started completely.\n      // However, don't wait forever, if we don't have a connection after 60 seconds: bail out!\n      //\n      int totalsleep = 0;\n      if ( getTrans().getParentTrans() != null ) {\n        while ( !isStopped() && !getTrans().getParentTrans().isRunning() ) {\n          try {\n            totalsleep += 10;\n            Thread.sleep( 10 );\n          } catch ( InterruptedException e ) {\n            stopAll();\n          }\n          if ( totalsleep > 60000 ) {\n            throw new KettleException( BaseMessages.getString(\n              PKG, \"MappingOutput.Exception.UnableToConnectWithParentMapping\", \"\" + ( totalsleep / 1000 ) ) );\n          }\n        }\n      }\n      // Now see if there is a target step to send data to.\n      // If not, simply eat the data...\n      //\n      if ( data.targetSteps == null ) {\n        logDetailed( BaseMessages.getString( PKG, \"MappingOutput.NoTargetStepSpecified\", getStepname() ) );\n      }\n    }\n\n    // Copy row to possible alternate rowset(s).\n    // Rowsets where added for all the possible targets in the setter for data.targetSteps...\n    //\n    putRow( data.outputRowMeta, r );\n\n    if ( checkFeedback( getLinesRead() ) ) {","sourceCodeStart":65,"sourceCodeEnd":101,"githubUrl":"https://github.com/pentaho/pentaho-kettle/blob/f3058517a153da500bf4551f46d79b91bf8ec552/engine/src/main/java/org/pentaho/di/trans/steps/mappingoutput/MappingOutput.java#L65-L101","documentation":"MappingOutput.processRow() waits for the parent mapping (Mapping sub-transformation) to wire up its input rowsets. If no connection from the parent's MappingInput arrives within 60 seconds (totalsleep > 60000, polled in 10ms sleeps), it throws this KettleException naming how many seconds elapsed. It means the sub-transformation never received data/configuration from its parent mapping step.","triggerScenarios":"Running a mapping sub-transformation whose MappingOutput step never gets connected by the parent's MappingInput — parent transformation not started, MappingInput/MappingOutput wiring removed, or the parent thread died before sending row metadata.","commonSituations":"Executing the sub-transformation standalone (debugging) instead of through a Mapping step; parent transformation aborted early; step name mismatches after renaming steps inside the mapping; deadlocked parent that never initializes its mapping children.","solutions":["Run the sub-transformation only via a parent transformation containing a 'Mapping' step — never standalone.","Verify the parent's Mapping step is correctly wired: MappingInput of parent connects to the sub-transformation's entry point.","Check that the parent transformation actually starts and initializes all steps (look for parent-side initialization errors in logs).","If the parent legitimately starts late, restructure so the mapping input is available sooner, or reduce unnecessary delays in the parent."],"exampleFix":"// before: executing sub-transformation directly\nTrans subTrans = new Trans(subTransMeta);\nsubTrans.execute(null);\n\n// after: run it through the parent mapping\nTrans parentTrans = new Trans(parentTransMeta);\nparentTrans.execute(null); // Mapping step initializes and feeds the sub-transformation\nparentTrans.waitUntilFinished();","handlingStrategy":"validation","validationCode":"// before running the sub-transformation, confirm it is invoked via a Mapping step\nboolean runViaMapping = transMeta.findMappingStepName() != null; // in parent context\n// or verify parent hop wiring in Spoon:// Mapping step's input mapping must map to this MappingOutput step","typeGuard":null,"tryCatchPattern":"try {\n  processRowLogic();\n} catch (KettleException e) {\n  if (e.getMessage().contains(\"UnableToConnectWithParentMapping\")) {\n    logError(\"MappingOutput never received configuration from parent MappingInput; check parent transformation wiring\", e);\n  }\n  setErrors(1);\n  stopAll();\n}","preventionTips":["Never execute mapping sub-transformation files standalone in production.","After renaming steps inside a mapping, re-verify the parent Mapping step's field mappings.","Ensure the parent transformation completes initialization before depending on mapping output.","Watch Spoon warnings about unconnected mapping input/output steps."],"tags":["kettle","mapping","timeout","sub-transformation"],"backgroundTag":"request-timeout","analyzedSha":"f3058517a153da500bf4551f46d79b91bf8ec552","analyzedAt":"2026-09-13T14:04:16.340Z","contentChangedAt":"2026-09-13T14:04:16.340Z","schemaVersion":2},"datasetVersion":"2026-09-20T23:17:15.980Z"}