The error is an internal exception within the Oracle Data Pump (impdp) utility. It occurs when a worker process encounters an unhandled state while preparing data for import, often leading to a premature job termination. Common Causes
Prevention is far more efficient than cure. To minimize the risk of ORA-39126:
Invalid objects related to the Data Pump utility or XML processing can trigger this error during the "prepare" phase. Unsupported Datatypes: Tables containing specific datatypes like
: Stale dictionary or fixed object statistics can confuse the Data Pump worker process during the "prepare" phase.
ORA-39126: Worker unexpected fatal error in KUPW-WORKER.PREPARE-DATA-IMP [worker_process_id] ORA-XXXXX: Underlying cause
If Data Pump continues to fail, export using legacy exp and import with imp (may lose advanced features but works for many data-only scenarios).
Short-term remediation steps
The error is an internal exception within the Oracle Data Pump (impdp) utility. It occurs when a worker process encounters an unhandled state while preparing data for import, often leading to a premature job termination. Common Causes
Prevention is far more efficient than cure. To minimize the risk of ORA-39126: ORA-39126: Worker unexpected fatal error in KUPW$WORKER
Invalid objects related to the Data Pump utility or XML processing can trigger this error during the "prepare" phase. Unsupported Datatypes: Tables containing specific datatypes like To minimize the risk of ORA-39126: Have you
: Stale dictionary or fixed object statistics can confuse the Data Pump worker process during the "prepare" phase. ORA-39126: Worker unexpected fatal error in KUPW$WORKER
ORA-39126: Worker unexpected fatal error in KUPW-WORKER.PREPARE-DATA-IMP [worker_process_id] ORA-XXXXX: Underlying cause
If Data Pump continues to fail, export using legacy exp and import with imp (may lose advanced features but works for many data-only scenarios).
Short-term remediation steps