Ora-39126 Worker Unexpected Fatal Error In Kupw-worker.prepare-data-imp 71 ((top)) Review

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

is a generic "unhandled exception" within the Data Pump worker process, typically occurring during the initial setup of an import job. While the code

identifies the specific internal routine failing, this error often stems from environment mismatches or corrupted Data Pump metadata. Potential Causes Permissions & Sessions : Running Data Pump as

can trigger unexpected behavior or performance issues; it is recommended to use a user with the DATAPUMP_IMP_FULL_DATABASE role instead. Metadata Corruption : The Data Pump packages or required views (like SYS.DBMS_METADATA ) might be invalid or missing. Version Mismatch

: Using a newer export version to import into an older database version without setting the parameter correctly. Resource Issues

: An empty or improperly configured default temporary tablespace can cause the worker process to fail during initial work item dispatch. Recommended Solutions

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

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.

5. Spatial Data (Oracle Spatial) Issues

The error code 71 is historically linked to spatial index or geometry validation issues. If your dump contains SDO_GEOMETRY columns and the target lacks Spatial components or has corrupted metadata, this error arises.

Solution 5: Apply Data Pump Fix Patches

Check for known bugs:

| Bug Number | Versions Affected | Description | |------------|-------------------|-------------| | 19728326 | 12.1.0.1, 12.1.0.2 | Worker fatal error with LOBs in partitioned tables | | 30578343 | 18c, 19.3-19.8 | Error 71 with XMLType or nested tables | | 35038710 | 19.9-19.14 | Corrupt worker state when importing stats | | 26257043 | 12.2, 18c | KUPW-ERROR 71 with deferred segment creation |

Apply the latest Data Pump Bundle Patch or upgrade to a stable version:

19.17+ (recommended)
21.9+

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.

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

Technical Breakdown (The Moral of the Story)

For those encountering this error in the wild, the story above highlights the key debugging steps:

The Error is a Symptom: ORA-39126 in KUPW$WORKER.PREPARE_DATA_IMP simply means a Data Pump worker thread failed while trying to prepare data for loading. It is rarely the root cause itself.
Look for the "Root Cause": You must look immediately above or below this error in the alert log or the Data Pump log file.
- Common Cause A: Tablespace Space (as in the story). The worker ran out of room to build the table.
- Common Cause B: Invalid Objects/Grants. The worker tried to compile a package or grant a privilege that didn't exist.
- Common Cause C: Corrupt Dump File. The worker tried to read a block from the .dmp file that was checksummed incorrectly.
Action: Once you identify the underlying error (like ORA-01653 or ORA-00942), fix that specific issue and restart the Data Pump job. The worker process will usually succeed on the second attempt.

The error ORA-39126: Worker unexpected fatal error in KUPW$WORKER.PREPARE_DATA_IMP [71] is a generic internal failure within the Oracle Data Pump import process. It typically indicates that the worker process encountered an unhandled exception while preparing for a data import, often triggered by inconsistent metadata, corrupt dictionary statistics, or invalid internal packages. Potential Causes

Stale or Corrupt Statistics: Stale dictionary or fixed object statistics are frequent culprits, causing Data Pump to miscalculate its execution plan.

Internal Package Issues: Corrupt or invalid KUPW$WORKER or DBMS_METADATA package bodies can prevent the worker from initializing correctly.

Schema Incompatibilities: Issues often arise when importing system-managed schemas (like SYSMAN or SYS) or when there are character set mismatches between the source and target environments.

Privilege Conflicts: Using the AS SYSDBA clause during import can sometimes trigger internal bugs; standard practice recommends using a user with DATAPUMP_IMP_FULL_DATABASE privileges instead. Troubleshooting and Solutions 1. Gather Fresh Dictionary and Fixed Object Statistics

Refreshing the database's internal statistics often resolves these internal worker errors.

-- Run these as a user with SYSDBA privileges EXEC DBMS_STATS.GATHER_DICTIONARY_STATS; EXEC DBMS_STATS.GATHER_FIXED_OBJECTS_STATS; Use code with caution. Copied to clipboard 2. Rebuild Data Pump Components ORA-39126: Worker unexpected fatal error in KUPW$WORKER

If the error persists after statistics are updated, the Data Pump utility itself may need to be reloaded to fix potential internal package corruption. Navigate to your $ORACLE_HOME/rdbms/admin directory. Run the following script as SYSDBA: @dpload.sql Use code with caution. Copied to clipboard

In Multitenant environments (12c and higher), ensure all PDBs are open before running this script. 3. Refine the Import Parameters

If specific objects are causing the crash, you can bypass them to finish the rest of the import.

Exclude Statistics: Add EXCLUDE=STATISTICS to your impdp command and gather them manually afterward.

Exclude System Schemas: If performing a full import, ensure you are excluding system-internal schemas by using EXCLUDE=SCHEMA:"IN ('SYSMAN', 'ORDDATA', 'WMSYS')".

Avoid SYSDBA: Run the import command as a standard user with the appropriate Data Pump roles instead of using / as sysdba. 4. Check for Specific Patches

Incident Review: ORA-39126 in kupw-worker.prepare-data-imp (PID 71)

Summary

On April 10, 2026, a worker process (kupw-worker.prepare-data-imp, worker ID 71) terminated with ORA-39126: "Worker unexpected fatal error".
This error occurred during Data Pump import (IMPDP) activity within the Data Pump worker tasked with preparing data for import.

Immediate impact

The specific import job failed to complete part or all of the load.
Dependent downstream tasks that expect the import to finish were blocked or delayed.
Potential partial objects or inconsistent import state left in the target schema/database.

Probable causes (ranked)

Corrupted or incompatible dump file or network/storage I/O error while reading the dump.
Resource exhaustion on the DB host (memory, CPU, temp space) causing worker crash.
Privilege or object-state conflict (invalid object, missing privileges, incompatible object definitions).
Bug in Data Pump or the specific version/patch of Oracle.
Unexpected session termination (OS kill, process crash, or ASM/FILESYSTEM disconnection).

Evidence to collect (immediately)

Import job log file (full trace) and dumpfile checksums.
Oracle alert.log and corresponding trace files timestamped at failure.
Worker process trace file under user_dump_dest/diag directories (look for ORA-39126 stack).
System resource metrics at failure time (vmstat, iostat, free memory, CPU).
Network/storage logs if dump files on NFS or remote storage.
Database version and patch level (SELECT * FROM v$version).
IMPDP parameters used (parfile or command line).
Any recent schema/object changes or incompatible types.

Short-term remediation steps

Stop and review the import job; note current state from DBA_DATAPUMP_JOBS and DBA_DATAPUMP_SESSIONS.
Examine the import log file and Oracle trace for the worker to identify exact exception/ORA- error chain.
Verify dumpfile integrity: compare checksums, run file copy locally to DB server and test read.
Check host resources and free space (including TEMP, FLASHBACK, and disk where dump resides).
Re-run import with PARALLEL=1 and LOGGING=TRUE to reduce concurrency and produce clearer logs.
If problem reproducible, run import on a test instance to isolate environmental issues.
If suspect Data Pump bug, gather trace and contact Oracle Support with ADRCI package of traces.

Long-term recommendations

Validate dumpfiles after export: retain checksums and test imports in staging before production runs.
Keep Oracle DB and Data Pump at recommended patch levels; monitor for relevant bug reports (Data Pump bugs).
Monitor host OS resources and configure alerts for memory, temp space, and I/O latency.
Use smaller dumpfile pieces or avoid high PARALLEL for unstable networks or storage.
Automate import pre-checks (disk space, dumps integrity, user privileges) before execution.

Suggested immediate next actions for you

Attach the import log and any worker trace snippets (stacktraces) from the time of ORA-39126.
Provide the IMPDP command/parfile, Oracle version/patch, and where dumpfile is stored (local/NFS).
If urgent, re-run with PARALLEL=1 and post the new log.

If you want, I can draft a concise incident report email for stakeholders including timeline, impact, and next steps — tell me the desired recipients and tone.

Related search suggestions (automatically generated)

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"kupw-worker.prepare-data-imp ORA-39126 trace"
"Data Pump import worker crash PARALLEL=1 workaround"

The error ORA-39126: Worker unexpected fatal error in KUPW$WORKER.PREPARE_DATA_IMP [71] is a generic internal error in Oracle Data Pump that typically indicates an unhandled exception within the worker process during the data import preparation phase. Root Causes

Stale or Corrupt Statistics: One of the most common triggers for ORA-39126 during the preparation or metadata loading phase is stale dictionary or fixed object statistics.

Importing System Schemas: Attempting to import internal system-related schemas (like SYSMAN, SYS, or SYSTEM) along with application schemas can lead to internal conflicts.

Data Pump Utility Corruption: The Data Pump packages or catalog objects themselves may be invalid or corrupted within the database.

Data Emoticons/Characters: Specific internal bugs (such as BUG 19712212) have linked this error to the presence of emoticons or unusual characters within table statistics that the worker fails to process.

Known Bugs: Versions such as 12.1.0.2 may be affected by BUG 28307854, specifically when importing package bodies after applying certain proactive bundle patches. Troubleshooting and Solutions

You can resolve this error by following these standard recovery steps:

Regenerate StatisticsRefreshing the dictionary and fixed object statistics often clears internal metadata mismatches: EXEC DBMS_STATS.GATHER_DICTIONARY_STATS; EXEC DBMS_STATS.GATHER_FIXED_OBJECTS_STATS;

Exclude Statistics from ImportIf the error persists during the statistics processing phase, bypass it by adding the following parameter to your impdp command: EXCLUDE=STATISTICS

You can then manually gather statistics after the data has successfully imported.

Rebuild Data Pump ComponentsIf internal packages are corrupted, you may need to reload the Data Pump utility:

For Oracle 12c and higher: Connect as SYSDBA and run @$ORACLE_HOME/rdbms/admin/dpload.sql.

For older versions: Run @$ORACLE_HOME/rdbms/admin/catdp.sql.

Avoid SYSDBA for ImportsStandard practice is to perform imports using a user with the DATAPUMP_IMP_FULL_DATABASE role (like SYSTEM) rather than using the AS SYSDBA connection, which can cause unexpected behavior in worker processes.

Target Specific SchemasEnsure you are only importing application-specific schemas and explicitly excluding system-maintained schemas to prevent internal worker failures. ensuring the temporary tablespace is valid

The database room was too quiet, which was usually a sign that something loud was about to happen.

Mark sat hunched over his monitor, the blue light reflecting off his glasses. It was 2:00 AM. He was overseeing a massive data migration—the kind of project that makes or breaks a DBA’s reputation. The Data Pump import had been running for six hours. Millions of rows were flowing from the old legacy system into the shiny new 19c container.

He refreshed the logs. Everything looked perfect. Total processed: 88%. Then, the cursor stopped blinking.

A single line of text bled across the console in jagged, white characters:

ORA-39126: Worker unexpected fatal error in KUPW$WORKER.PREPALE_DATA_IMP [71]ORA-01403: no data found

Mark felt a cold drop of sweat slide down his neck. ORA-39126 wasn’t just a regular error; it was a "worker" error. The internal plumbing of the Oracle Data Pump engine had just burst, and the "71" at the end was a cryptic pointer to a specific failure point in the PL/SQL package.

He checked the worker status. Terminated. The entire import job had stalled, frozen in a state of digital rigor mortis.

"No data found?" Mark whispered to the empty office. "How can there be no data found during an import?"

He dove into the trace files. The error wasn't coming from his data; it was coming from the metadata. The KUPW$WORKER package—the brain of the operation—had gone looking for instructions on how to handle a specific table and found a void instead.

He realized what had happened. A developer had dropped a temporary table on the source system exactly as the export began, leaving a ghost entry in the export dump. The import worker reached for the ghost, found nothing, and panicked.

Mark didn't have time to restart the whole six-hour process. He had to perform surgery.

Using the DBMS_DATAPUMP API, he manually attached to the ghost job. He signaled the worker to skip the corrupted object, essentially telling the engine to "ignore the ghost." He held his breath and issued the command: START_JOB.

The fans in the server rack roared. The logs began to scroll again. 90%... 95%... 100%.

As the sun began to peek through the office blinds, the terminal finally displayed the words he’d been chasing all night: Job "SYS_IMPORT_FULL_01" successfully completed.

Mark leaned back, his coffee cold and his eyes burning, and closed the laptop. The ghost was gone. 🛠️ Key Takeaways for ORA-39126 [71]

Internal Failure: This is an unhandled exception within the KUPW$WORKER PL/SQL package. Common Causes: Metadata inconsistencies in the export file.

Bugs in specific Oracle versions (often fixed in later Patch Sets). Conflicts with "External Tables" or "Virtual Columns." The Fix:

Check the Alert Log and Trace Files for the underlying ORA- code (often ORA-01403).

Try the import again using EXCLUDE=STATISTICS (a frequent culprit).

Apply the latest RU (Release Update) to fix known Data Pump bugs. To help you fix this for real, let me know: What Oracle version are you on?

What was the underlying error in the trace file? (e.g., ORA-01403, ORA-06512) Are you importing specific schemas or a full database?

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

is a generic internal error in Oracle Data Pump that typically indicates an unhandled exception within a worker process. The specific code

often points to an issue during the initialization phase where the worker is preparing for data import. Oracle Communities Potential Causes Corrupted Data Pump Metadata

: The internal packages or views used by Data Pump may be invalid or corrupted. Missing or Incorrect Tablespaces

: If the default temporary tablespace is missing or empty, Data Pump cannot manage the metadata for the import job. Schema Conflicts : Attempting to import system schemas (like ) along with application data can trigger this fatal error. Privilege Issues : Sometimes granting IMP_FULL_DATABASE

to a non-system user can cause unexpected behavior in certain environments. Bug-related issues

: Specific versions of Oracle have known bugs (e.g., bug 28307854) that cause ORA-39126 when importing package bodies or certain metadata. Oracle Forums Common Solutions and Workarounds To resolve this error, try the following steps in order:

The ORA-39126 error during Data Pump import generally indicates a metadata corruption issue or a conflict involving statistics, often manifesting as an ORA-01403 "no data found" error. Common solutions involve excluding statistics (EXCLUDE=STATISTICS) during the import or revalidating the Data Pump components using dpload.sql.For further discussion on this error, see the Oracle Support Community.

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

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.

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

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:

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

Check the import log: Review the import log file for any previous errors or warnings that may have contributed to this error.
Verify data integrity: Check the data for corruption or inconsistencies.
Increase resources: Ensure that the system has sufficient resources (e.g., memory, CPU) to perform the import.
Check Data Pump versions: Verify that the Data Pump versions used for export and import are compatible.
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.

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" occurs during an Oracle Data Pump import operation (using impdp). It indicates that a worker process encountered a critical, unexpected failure while preparing to load data into a table or partition.

Step 8: Recreate the Dump File

If all else fails, return to the export step:

Ensure FILESIZE limits are not creating multiple fragments
Use COMPRESSION=ALL to reduce corruption risks
Transfer using rsync or binary FTP
Validate checksums (DBMS_DATAPUMP.GET_DUMP_FILE_INFO)