To minimize the risk of encountering the ORA-39126 error, follow these best practices:
: Migration from Oracle 12c to 19c. impdp fails with:
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: To minimize the risk of encountering the ORA-39126
Try performing the import without REMAP_TABLESPACE into a staging area, or check Oracle Support (MOS) for patch 27634993 . Summary Checklist Quick Fix: Add EXCLUDE=STATISTICS to your command. Cleanup: Ensure utlrp.sql has been run.
General solutions involve checking system resources and making configuration changes. Summary Checklist Quick Fix: Add EXCLUDE=STATISTICS to your
Check the Alert Log and Trace FilesData Pump errors in the console are often vague. To find the "real" underlying error (like an ORA-00600 or ORA-07445), you must look deeper.
This often bypasses the internal planning logic error in KUPW-WORKER . Check the Alert Log and Trace FilesData Pump
In many documented cases, the underlying error is ORA-01403: no data found , which is accompanied by ORA-06512 in the stack trace. The worker is executing a SQL query or a PL/SQL operation that expects to find a row but returns no results. This mismatch between the worker's expectation and the actual data dictionary state triggers the fatal error. The cause is often a logical inconsistency in the Data Pump's internal metadata, rather than a conventional data corruption issue. Oracle has documented this in various support notes, attributing it to specific bugs in different versions.
If this error persists, it is recommended to check the alert log for additional ORA- errors and consider raising an SR with Oracle Support.
In Multitenant environments (12c and higher), ensure all PDBs are open before running this script. 3. Refine the Import Parameters
ORA-39126: Worker unexpected fatal error in KUPW$WORKER.PREPARE_DATA_IMP [71]