Ora-39126 Worker Unexpected | Fatal Error In Kupw-worker.prepare-data-imp 71

If the error persists, generate more detail to identify the exact object causing the crash: Add TRACE=480300 to the impdp command.

impdp ... TRANSFORM=LOB_STORAGE:BASICFILE TRANSFORM=SEGMENT_ATTRIBUTES:N

Before diving into complex fixes, perform these initial steps to isolate the problem:

The ORA-39126 error is not a single issue but a symptom of many potential problems. The official Oracle documentation defines it as an internal error, but in practice, the root causes often fall into the following categories: If the error persists, generate more detail to

: Migration from Oracle 12c to 19c. impdp fails with:

Try adding TRANSFORM=DISABLE_ARCHIVE_LOGGING:Y or TRANSFORM=SEGMENT_ATTRIBUTES:N .

The source dump contains tablespaces that do not exist on the target, or the user mapping the tablespaces is encountering issues. The official Oracle documentation defines it as an

ORA-39126: Worker unexpected fatal error in KUPW$WORKER.PREPARE_DATA_IMP [71] — oracle-mosc

Then review and manually execute the DDL, adjusting problem columns.

The specific message ending with [71] provides a powerful clue. In the context of the KUPW worker, the numeric code points to the exact point of failure. When you see "prepare-data-imp 71", it indicates that the worker encountered an issue while preparing for the data import, specifically during an attempt to populate a table. This phase is critical for setting up the import environment. ORA-39126: Worker unexpected fatal error in KUPW$WORKER

Review the resulting trace file to see the last SQL statement or object type handled before block 71 failed. Proven Solutions and Workarounds

Corruption in the Data Pump catalog packages ( SYS.KUPW$WORKER ) can cause failures. Recompiling these components can resolve the issue. To do this:

SELECT object_name, object_type, status FROM dba_objects WHERE status = 'INVALID';

: Run the following on the source database to ensure no invalid objects are exported, as they can trigger internal errors.