Ora-39126 Worker Unexpected Fatal Error In Kupw-worker.prepare-data-imp 71 [extra Quality] [FAST]

ORA-39126 is a generic "Worker unexpected fatal error" that occurs during Oracle Data Pump operations. The specific sub-program KUPW$WORKER.PREPARE_DATA_IMP [71] typically points to an internal failure while the worker is preparing to import data rows into a table. Primary Causes & Solutions

Refresh Dictionary StatisticsClear out potential confusion in the optimizer by gathering fresh internal stats: EXEC DBMS_STATS.GATHER_DICTIONARY_STATS; EXEC DBMS_STATS.GATHER_FIXED_OBJECTS_STATS;. ORA-39126 is a generic "Worker unexpected fatal error"

3. Identify the Failing Table

Look for the table name in the error context or use: Always transfer

often points to an issue during the initialization phase where the worker is preparing for data import. Oracle Communities Potential Causes Corrupted Data Pump Metadata ORA-39126 is a generic "Worker unexpected fatal error"

Prevention

• Always transfer .dmp files in binary mode
• Ensure NLS_LANG matches between source and target
• Use the same Oracle version (or newer target, but not older) for export/import
• Validate dump files with impdp ... validate=full before production import
• Set FILESIZE to split large dumps rather than creating multi-gigabyte single files