Ora-39126 Worker Unexpected Fatal Error In Kupw-worker.prepare-data-imp 71 Exclusive
If validation fails, re-export the source data.
If the error persists, the dump file is likely irrecoverably corrupted, and you will need to recreate it from the source.
The ORA-39126 error is a generic internal error triggered by the Oracle Data Pump (Data Pump) utility. When it specifically points to KUPW-WORKER.PREPARE-DATA-IMP [71] , it indicates that the Data Pump Worker process encountered an unexpected state while preparing to import data.
A previous stalled or crashed Data Pump job can leave orphaned master tables behind, causing subsequent worker processes to fail. Clean up old metadata before restarting: If validation fails, re-export the source data
The Database Control ( dbconsole ) or Oracle Enterprise Manager (OEM) can be useful for monitoring Data Pump jobs. However, for deep diagnostic detail, the command line with the TRACE option is generally more effective. If these steps don't resolve the problem, the final step is to contact Oracle Support. They can access internal bug databases and provide backports if your specific version lacks a fix. Always have the Data Pump log file and relevant trace files ready when opening a Service Request.
It processed the metadata. It hit the "Prepare Data" phase—the exact spot where it had died ten minutes ago. This time, with the extra gigabytes of breathing room, the worker didn't crash.
According to Oracle’s official documentation, ORA-39126 signifies that "An unhandled exception was detected internally within the worker process for the Data Pump job. This is an internal error". In essence, a slave process responsible for performing a subtask (unloading, transforming, or loading data) encountered an unexpected exception that the system’s internal exception handlers could not recover from. When it specifically points to KUPW-WORKER
The structure of the error message is critical for diagnosis:
It didn’t stop with a gentle "Job completed" message. It stopped with a violent, jagged block of text that turned his stomach into a knot.
Ensure the export was completed without errors. Check the expdp log file for any previous warnings. If possible, attempt to import the same dump on a different server to verify if it is a source issue or a target environment issue. Example Solution Scenario However, for deep diagnostic detail, the command line
Check the Data Pump trace directory for worker trace files ( *dw*.trc ). Look for errors like ORA-01403: no data found , ORA-00942: table or view does not exist , or LPX-00210: expected AS exhibited . Step 2: Verify Database Component Validity
Try the import again using EXCLUDE=STATISTICS (a frequent culprit).
: During an impdp operation, the Data Pump master process creates a snapshot of the metadata to be imported. If there is a mismatch or corruption in the SYS.KU$_xxx master tables (specifically the SYS_IMPORT_SCHEMA_xx tables), the worker process cannot find the data it expects, throwing a "no data found" exception and wrapping it as ORA-39126.
Refreshing the database's internal statistics often resolves these internal worker errors.
