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

Troubleshooting ORA-39126: Worker Unexpected Fatal Error in KUPW$WORKER.PREPARE_DATA_IMP [71]

If you are seeing the ORA-39126 error during an Oracle Data Pump Import (IMPDP), specifically referencing KUPW$WORKER.PREPARE_DATA_IMP [71], you have likely hit a snag in the metadata preparation phase. This error is a "catch-all" for unexpected internal worker failures, and the suffix [71] usually points to a specific issue with how the worker process is handling table data or partitioned objects. What Causes ORA-39126 (Internal Error 71)?

The error occurs when the Data Pump worker process encounters a condition it doesn't know how to handle. In the context of PREPARE_DATA_IMP [71], the most common culprits are:

Metadata Inconsistency: The source database has orphaned entries in the data dictionary or "ghost" partitions that the export file is trying to recreate.

Invalid Objects: The schema being imported contains invalid spatial indexes, functional indexes, or complex constraints that fail during the "prepare" phase.

Statistics Mismatch: Issues with importing table statistics, especially on partitioned tables, can trigger this internal logic error.

Version Disparity: Importing a dump file from a much higher Oracle version into a lower version without using the VERSION parameter correctly. Step-by-Step Solutions 1. Exclude Statistics

The most frequent cause of error [71] is a failure in processing table statistics. You can bypass this by excluding statistics during the import and gathering them manually later. Add this parameter to your impdp command: EXCLUDE=STATISTICS Use code with caution.

If the import succeeds, run DBMS_STATS.GATHER_SCHEMA_STATS after the data is loaded. 2. Recompile Invalids on Source and Target

Data Pump can choke on metadata for objects that are in an INVALID state.

Run utlrp.sql on both the source (before export) and the target database to ensure all objects are valid.

If you cannot re-export, try using EXCLUDE=INDEX or EXCLUDE=CONSTRAINT to see if the worker moves past the error. 3. Use the VERSION Parameter

If you are moving data between different Oracle versions (e.g., 19c to 12c), ensure you used the VERSION parameter during the export (EXPDP). If you didn't, try adding it to your import command: VERSION=12.1 (or your target version) Use code with caution. 4. Check for Corrupt Metadata

Sometimes the error is caused by a specific table. To find out which one, increase the logging detail: TRACE=480300 Use code with caution.

Check the resulting trace files in your DIAGNOSTIC_DEST. Look for the last object processed before the "Fatal Error." You can then try running the import again while excluding that specific table: EXCLUDE=TABLE:"IN ('PROBLEM_TABLE_NAME')" Use code with caution. 5. Patching and Bug 27634993

There is a known Oracle bug related to KUPW$WORKER where imports fail when REMAP_TABLESPACE is used alongside certain partitioned objects.

Workaround: 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. Data corruption : Data corruption during the export

Investigation: Use TRACE=480300 to find the specific table causing the crash.

Dictionary: Check DBA_RESUMABLE to see if the worker is actually stuck on a space issue rather than a logic error.

The error ORA-39126: Worker unexpected fatal error in KUPW$WORKER.PREPARE_DATA_IMP [71] is a generic "catch-all" internal error during an Oracle Data Pump import (impdp). It typically signifies an unhandled exception triggered by corrupted metadata, invalid system objects, or specific version incompatibilities. Common Root Causes

Stale or Corrupt Statistics: Stale dictionary or fixed object statistics can confuse the Data Pump worker process during the "prepare" phase.

Invalid Data Pump Metadata: If the Data Pump internal packages (like KUPW$WORKER) are invalid or have become desynchronized, they will fail to process the import stream.

Unsupported Schema Import: Attempting to import system-related schemas (e.g., SYSMAN, XDB) across different versions or platforms frequently triggers this error.

Version Incompatibility: Specific bugs (e.g., Bug 28307854) in certain patch levels (like 12.1.0.2) can cause fatal errors when importing package bodies. Recommended Troubleshooting Steps

Revalidate and Rebuild Data Pump PackagesOften, the utility itself needs a reset. You can rebuild the Data Pump components by running these scripts as SYS: @$ORACLE_HOME/rdbms/admin/catdpx.sql

@$ORACLE_HOME/rdbms/admin/utlrp.sql (to recompile any resulting invalid objects).

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;.

Exclude Statistics from the ImportIf the error occurs while processing statistics, bypass them during the import and gather them manually later: Add EXCLUDE=STATISTICS to your impdp command line.

Narrow the Import ScopeIf migrating between different OS types or major versions (e.g., 11g Windows to 12c Linux), avoid importing all schemas at once. Explicitly include only your application schemas and exclude system schemas: EXCLUDE=SCHEMA:"IN ('SYSMAN', 'XDB', 'WMSYS')".

Check for Known PatchesCheck My Oracle Support for specific bug IDs like 28307854 or 18393005 if your database is on version 12.1 or 12.2, as these have known issues with ORA-39126.

Could you provide your Oracle Database version and the full impdp command you are running to help identify a more specific fix?

The Oracle error ORA-39126: Worker unexpected fatal error in KUPW$WORKER.PREPARE_DATA_IMP [71] is a generic "catch-all" internal error during a Data Pump import (impdp). It typically indicates that a worker process encountered an unhandled exception while preparing data for insertion. Primary Causes

Stale or Corrupt Dictionary Statistics: Inconsistent metadata in the database dictionary often causes the internal KUPW$WORKER package to fail. Additional information: The error is occurring in the

Metadata Corruption: Corruption within the Data Pump utility or the DBMS_METADATA package can prevent the worker from correctly interpreting the dump file.

PDB Metadata Mismatch: If you are using Oracle 12c or higher, this error often occurs in Pluggable Databases (PDBs) where the Data Pump catalog is invalid or incomplete, frequently after a remote clone.

Empty Temporary Tablespace: While less common for code [71], an empty or incorrectly configured default temporary tablespace can trigger ORA-39126. Recommended Resolutions 1. Rebuild Data Pump Catalog

For most modern Oracle versions (12c+), the most effective fix is to rebuild the Data Pump utility packages to clear internal corruption.

Navigate to the admin directory: cd $ORACLE_HOME/rdbms/admin Execute as SYSDBA: SQL> @dpload.sql Use code with caution. Copied to clipboard

Note: In a Multitenant environment, ensure all PDBs are open and run this from the CDB. 2. Refresh Dictionary Statistics

Corrupt statistics can cause the worker to miscalculate data preparation. Run the following as SYSDBA:

exec dbms_stats.gather_dictionary_stats; exec dbms_stats.gather_fixed_objects_stats; Use code with caution. Copied to clipboard 3. Targeted Exclusion

If the error persists and is linked to specific objects, you can bypass the failure by excluding statistics or problematic schemas. Add EXCLUDE=STATISTICS to your impdp command.

If migrating between versions (e.g., 11g to 12c), avoid importing system schemas like SYSMAN or WMSYS. 4. Validate Environment Configuration

Temporary Tablespace: Ensure the default temporary tablespace is correctly assigned and has active tempfiles.

Check Invalid Objects: Run a script like utlrp.sql to recompile any invalid system packages, particularly those owned by SYS or XDB.

For more specific guidance, you can check the Oracle Community Discussion or consult Oracle Support Doc ID 1508068.1 on My Oracle Support.

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 ensuring a clean

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:

• Analyze the import log and error files
• Check for any known issues or patches related to this error
• Perform additional troubleshooting steps
• Provide guidance on recovering the import process, if possible.

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

Real-World Example: Resolving Error 71

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

ORA-39126: Worker unexpected fatal error in KUPW-WORKER.PREPARE-DATA-IMP [71]
ORA-06550: line 1, column 7: PLS-00201: identifier 'SDO_UTIL.GETNUMELEM' must be declared

Root Cause: The target database lacked Oracle Spatial license or had MDSYS schema invalid objects.

Solution:

1. Verify Spatial installation: SELECT * FROM dba_registry WHERE comp_name LIKE '%Spatial%';
2. Run @?/md/admin/mdinst.sql (as SYS) to install Spatial components.
3. Recompile invalid objects: EXEC utl_recomp.recomp_serial();
4. Rerun impdp – success.

What is ORA-39126?

The full error message usually appears as:

ORA-39126: Worker unexpected fatal error in KUPW-WORKER.PREPARE-DATA-IMP 
[worker_process_id] 
ORA-XXXXX: Underlying cause

• ORA-39126: Indicates an unexpected fatal error in a Data Pump worker process.
• KUPW-WORKER: Kernel Utility Process Worker – the background process handling Data Pump execution.
• PREPARE-DATA-IMP: The phase where the import worker prepares to load data into a table (e.g., parsing data, converting data types, allocating buffers, handling LOBs/XMLTypes).
• [71]: This number often refers to a specific internal sub-component or error context. In many Oracle versions, code 71 relates to issues with spatial data, XML schema validation, or row processing failures. However, it can also be a generic pointer to a failure during data preparation.

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

Remediation Strategies

Once the likely cause is identified, several strategies can be employed:

• For Corrupted Dump Files: Re-export the data from the source, ensuring a clean, binary transfer. Use FLASHBACK_TIME or consistent export parameters to avoid inconsistencies.
• For Metadata Conflicts: Use the EXCLUDE=TABLE_DATA parameter to import only the table definitions. Then, manually create missing types or schemas. After resolving metadata, use CONTENT=DATA_ONLY to import just the rows.
• For Known Bugs: Apply the relevant patch (e.g., one-off patch for Bug 19783189) or upgrade the Oracle client and database to a fixed version. A temporary workaround is to set PARALLEL=1 and add TRANSFORM=DISABLE_ARCHIVE_LOGGING:Y to simplify the worker’s task.
• As a Last Resort: Isolate the problematic table. Exclude it using EXCLUDE=TABLE:"IN ('PROBLEM_TABLE')" and import everything else. Then, manually move the problematic table using a different method (e.g., old exp/imp, external tables, or database links).

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

1. Check the full error log

Run impdp with LOGFILE and TRACE to see preceding errors:

impdp user/pwd DIRECTORY=dp_dir DUMPFILE=exp.dmp LOGFILE=imp.log TRACE=480300