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

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

a Data Pump internal error that typically occurs when the worker process encounters an unhandled exception during the preparation phase of an import . The specific code is often associated with underlying ORA-01403: no data found errors in the internal Data Pump packages. Oracle Communities Likely Causes Data Pump Metadata Corruption:

Internal Data Pump packages or objects may be in an inconsistent state. Stale Dictionary Statistics:

Outdated statistics on internal dictionary tables or fixed objects can cause Data Pump to fail during its preparation queries. Invalid Objects: Dependent objects like SYS.KUPW$WORKER SYS.DBMS_METADATA might be invalid. Empty Temporary Tablespace:

If the temporary tablespace is empty or incorrectly configured, internal sort/join operations during import preparation can fail. WordPress.com Recommended Solutions Gather Dictionary Statistics: ORA-39126: Worker unexpected fatal error in KUPW$WORKER

Refresh internal metadata statistics to ensure the Data Pump worker can execute its internal queries correctly.

EXEC DBMS_STATS.GATHER_DICTIONARY_STATS; EXEC DBMS_STATS.GATHER_FIXED_OBJECTS_STATS; Use code with caution. Copied to clipboard Rebuild Data Pump Utility:

If internal corruption is suspected, reload the Data Pump metadata objects. For 12c and higher: @?/rdbms/admin/dpload.sql (for CDB/PDB environments, ensure PDBs are open). For older versions (10g/11g): @?/rdbms/admin/catdp.sql @?/rdbms/admin/catmetx.sql Check for Invalid Objects: Ensure all objects are valid. owner, object_name, object_type dba_objects Use code with caution. Copied to clipboard Recompile any invalid objects using the @?/rdbms/admin/utlrp.sql Verify Temporary Tablespace:

Ensure the database has a functioning default temporary tablespace with datafiles attached. tablespace_name dba_temp_files; Use code with caution. Copied to clipboard Exclude Statistics during Import: Solution 6: Manually Pre-create Tables

Sometimes the error is triggered by the import of statistics themselves. Try adding EXCLUDE=STATISTICS

command and gather them manually after the import completes. WordPress.com If these steps do not resolve the issue, check the trace files generated in the directory for a more specific error code (like ) following the ORA-39126 message. Oracle Communities Are you running this import on a Multitenant (CDB/PDB) architecture or a

Solution 6: Manually Pre-create Tables

  1. Extract DDL with impdp sqlfile
  2. Fix any mismatched column definitions
  3. Create tables without constraints
  4. Import with TABLE_EXISTS_ACTION=TRUNCATE (not REPLACE):
impdp ... table_exists_action=truncate

7. Insufficient Memory or PGA

The worker process requires enough Program Global Area (PGA) to prepare data, especially for large rows, LOBs, or row batches. If PGA_AGGREGATE_TARGET is too low, the worker may abort.

3. Identify the Failing Table

Look for the table name in the error context or use: Extract DDL with impdp sqlfile Fix any mismatched

-- Query Data Pump master table if import was running
SELECT object_name, object_type, status, error_count
FROM "<schema>"."<job_name>_MASTER"
WHERE status = 'ERROR';

5. Check target table structure

Compare source and target table definitions (columns, data types, partitions). Use SQLFILE parameter to extract DDL from dump:

impdp ... SQLFILE=create_tables.sql

2. Verify the dump file integrity

# Use DBMS_DATAPUMP to validate
impdp user/pwd DIRECTORY=dp_dir DUMPFILE=exp.dmp SQLFILE=check.sql

If validation fails, re-export the source data.

Preventive Best Practices

To avoid this error in the future:

  1. Standardize Oracle Versions – Export and import between the same patch level when possible.
  2. Use VERSION parameter – On export, use VERSION=LATEST or match target version.
  3. Validate before import – Use SQLFILE parameter to generate DDL and review for compatibility.
  4. Monitor space and memory – Ensure target tablespaces and PGA are sized adequately.
  5. Test with CONTENT=DATA_ONLY – Separate metadata and data imports to isolate issues.
  6. Regularly check invalid objects – In both source and target databases.