Ora-39126 Worker Unexpected Fatal Error In Kupw-worker.prepare-data-imp 71 ^new^ Link

The ORA-39126 error in KUPW$WORKER.PREPARE_DATA_IMP [71] indicates an internal Data Pump failure during import, often caused by corrupted Data Pump catalogs, PDB/CDB mismatches, or issues within the temporary tablespace. Resolving the issue typically involves validating the Data Pump catalog, ensuring the temporary tablespace is valid, or using the EXCLUDE=STATISTICS parameter. For a detailed troubleshooting guide, refer to Oracle Communities

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

The error ORA-39126: Worker unexpected fatal error in KUPW$WORKER.PREPARE_DATA_IMP [71] is an internal exception within the Oracle Data Pump (impdp) utility. It occurs when a worker process encounters an unhandled state while preparing data for import, often leading to a premature job termination. Common Causes

This specific error is frequently linked to metadata inconsistencies or environment-specific bugs:

Malformed Statistics: Stale or corrupt optimizer statistics in the source dump file can cause the worker to crash during the preparation phase.

Invalid Data Pump Components: If the Data Pump internal packages (like KUPW$WORKER) or the database catalog are invalid or out of sync, workers will fail.

Permission Issues: Running the import as SYSDBA rather than a standard user with DATAPUMP_IMP_FULL_DATABASE privileges can lead to unexpected behavior.

System Schema Conflicts: Attempting to import system-related schemas (like SYSMAN) across different Oracle versions (e.g., 11g to 12c) often triggers internal preparation errors. Troubleshooting and Resolution Steps 1. Rebuild Data Pump Metadata

If the issue is caused by a corrupt Data Pump catalog, you can re-register the components by running the dpload.sql script as a SYSDBA user:

-- For Container Databases (CDB), ensure all PDBs are open first ALTER PLUGGABLE DATABASE ALL OPEN; -- Run the script from the rdbms/admin directory @?/rdbms/admin/dpload.sql Use code with caution.

After running this, recompile any remaining invalid objects using the utlrp.sql script. 2. Exclude Statistics

ORA-39126 Worker Unexpected Fatal Error in KUPW-Worker.Prepare-Data-Imp 71: Causes, Solutions, and Troubleshooting Steps

The ORA-39126 error is a critical issue that can occur during data import operations using Oracle Data Pump, a utility that enables you to export and import data and metadata from one database to another. This error is specifically related to the KUPW-Worker.Prepare-Data-Imp 71 process, which is a worker process responsible for preparing data for import. The ORA-39126 error in KUPW$WORKER

Understanding the ORA-39126 Error

The ORA-39126 error message typically appears as follows:

ORA-39126: Worker unexpected fatal error in KUPW-Worker.Prepare-Data-Imp 71

This error indicates that a worker process encountered an unexpected fatal error while preparing data for import. The error can occur due to various reasons, including:

  1. Insufficient System Resources: The system may not have sufficient resources, such as memory or CPU, to handle the import operation.
  2. Data Corruptions: Data corruptions or inconsistencies in the export file can cause the worker process to fail.
  3. Database Configuration Issues: Incorrect database configuration, such as inadequate temporary space or incorrect character set settings, can lead to the ORA-39126 error.
  4. Import Parameter Settings: Incorrect import parameter settings, such as insufficient memory allocation or incorrect data type mappings, can cause the error.

Causes of the ORA-39126 Error

To troubleshoot the ORA-39126 error, it's essential to understand the underlying causes. Some common causes include:

  1. Inadequate Temporary Space: Insufficient temporary space can cause the worker process to fail while preparing data for import.
  2. Data Type Mismatches: Data type mismatches between the source and target databases can lead to errors during the import process.
  3. Character Set Issues: Character set mismatches or incorrect character set settings can cause data corruptions or inconsistencies.
  4. LOB or BFILE Data Issues: Issues with LOB (Large OBject) or BFILE (Binary File) data, such as incorrect storage or invalid data, can cause the worker process to fail.

Solutions and Troubleshooting Steps

To resolve the ORA-39126 error, follow these troubleshooting steps:

  1. Check System Resources: Ensure that the system has sufficient resources, such as memory and CPU, to handle the import operation.
  2. Verify Export File Integrity: Check the export file for data corruptions or inconsistencies using tools like impdp with the VERIFY option.
  3. Adjust Import Parameters: Adjust import parameter settings, such as increasing memory allocation or modifying data type mappings, to ensure compatibility with the target database.
  4. Increase Temporary Space: Ensure that the target database has sufficient temporary space to handle the import operation.
  5. Check Character Set Settings: Verify that character set settings are correct and consistent between the source and target databases.
  6. Use the SKIP_UNUSABLE_INDEXES Parameter: Set the SKIP_UNUSABLE_INDEXES parameter to Y to skip indexes that are not usable during the import process.
  7. Use the SQLFILE Option: Use the SQLFILE option to generate a SQL file that can be used to recreate the import operation.

Best Practices to Avoid the ORA-39126 Error

To minimize the risk of encountering the ORA-39126 error, follow these best practices:

  1. Test Export and Import Operations: Test export and import operations in a non-production environment to ensure compatibility and identify potential issues.
  2. Monitor System Resources: Monitor system resources during import operations to ensure sufficient resources are available.
  3. Use Compatible Character Sets: Use compatible character sets between the source and target databases.
  4. Verify Data Integrity: Verify data integrity before and after import operations using tools like DBVERIFY or impdp with the VERIFY option.
  5. Regularly Maintain Database Statistics: Regularly maintain database statistics to ensure accurate data distribution and prevent data skew.

Conclusion

The ORA-39126 error can be a critical issue during data import operations using Oracle Data Pump. Understanding the causes, solutions, and troubleshooting steps can help database administrators and developers resolve the error efficiently. By following best practices and monitoring system resources, data integrity, and character set settings, you can minimize the risk of encountering the ORA-39126 error and ensure successful data import operations. Insufficient System Resources : The system may not

A very specific Oracle error!

ORA-39126 is a Data Pump error that occurs when there is an issue with the worker process. Here's a breakdown of the error:

ORA-39126: Worker unexpected fatal error in KUPW_WORKER.PREPARE_DATA_IMP

This error typically indicates that a worker process, which is responsible for executing a specific task during the import operation, encountered an unexpected fatal error while preparing data for import.

Possible causes:

  1. Data corruption: Data corruption during the export or import process can cause this error.
  2. Insufficient resources: Inadequate resources, such as memory or CPU, can lead to worker process failures.
  3. Data Pump version mismatch: A mismatch between the Data Pump versions used for export and import can cause compatibility issues.
  4. Database character set issues: Character set mismatches or invalid characters in the data can cause errors during import.
  5. Internal errors: Rarely, internal errors in the Data Pump code can cause this error.

Additional information:

The error is occurring in the KUPW_WORKER.PREPARE_DATA_IMP procedure, which is part of the Data Pump worker process. The error code is 71, which is an internal Oracle error code.

Troubleshooting steps:

  1. Check the import log: Review the import log file for any previous errors or warnings that may have contributed to this error.
  2. Verify data integrity: Check the data for corruption or inconsistencies.
  3. Increase resources: Ensure that the system has sufficient resources (e.g., memory, CPU) to perform the import.
  4. Check Data Pump versions: Verify that the Data Pump versions used for export and import are compatible.
  5. Try a different import method: If possible, try using a different import method, such as a conventional import or a transportable tablespace import.

Oracle Support or further assistance:

If you are unable to resolve the issue using the above steps, you may want to engage Oracle Support or a certified Oracle professional for further assistance. They can help you:

This error, ORA-39126: Worker unexpected fatal error in KUPW-WORKER.PREPARE-DATA-IMP 71, occurs during an Oracle Data Pump import (using impdp). It is a generic "catch-all" fatal error indicating that a worker process died unexpectedly while preparing to load data into a table.

The "71" refers to a specific internal trace point in the Data Pump code. It almost always indicates metadata or data corruption in the dump file, object definition incompatibility, or a bug in the Data Pump client/database version. Causes of the ORA-39126 Error To troubleshoot the

Step 6: Check and Alter Target Table Definition

Before importing the failing table, manually create it with more forgiving attributes:

Example:

ALTER TABLE problematic_table DISABLE ALL TRIGGERS;
ALTER TABLE problematic_table MODIFY lob_column (lob_storage AS basicfile);

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

Solutions

Step 7: Increase PGA and Worker Resources

During the import, monitor PGA usage:

SELECT * FROM v$pgastat;

Increase PGA_AGGREGATE_TARGET dynamically:

ALTER SYSTEM SET PGA_AGGREGATE_TARGET=2G SCOPE=BOTH;

Also, reduce the number of parallel workers:

impdp ... PARALLEL=1

4. Increase parallel workers carefully

Sometimes reducing or increasing PARALLEL helps:

impdp ... PARALLEL=1   # or match CPU cores

Step 5: Use the TRANSFORM Option to Bypass Issues

If the problem relates to storage or segments:

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

The latter disables tablespace and storage clauses, allowing the import to use target defaults.

The Investigation

The log file was messy. The error was followed by a cascade of Java stack traces, looking like digital debris after a car crash. He scrolled past the ORA-39126 to find the root cause buried beneath it.

ORA-01653: unable to extend table SYSTEM.SYS_EXPORT_TABLE_01 by 1024 in tablespace USERS

Arthur let out a breath he didn’t know he was holding. It wasn’t corruption. It wasn't a hardware failure. The worker process—KUPW$WORKER—had tried to prepare a chunk of data for import, hit a wall, and threw its hands up in a "fatal error."

The Data Pump worker process had essentially walked into a room that was already full. The tablespace where the temporary import tables were being built had run out of space. Because it couldn't write the data it was preparing, the worker process crashed, triggering the generic ORA-39126 alert.