Ora-39126 Worker Unexpected Fatal Error In Kupw-worker.prepare-data-imp 71 Jun 2026

According to Oracle’s official documentation, ORA-39126 signifies that "An unhandled exception was detected internally within the worker process for the Data Pump job. This is an internal error". In essence, a slave process responsible for performing a subtask (unloading, transforming, or loading data) encountered an unexpected exception that the system’s internal exception handlers could not recover from.

Run the Import with METRICS=YESAdd METRICS=YES and LOGTIME=ALL to your IMPDP command. This provides a more granular view of exactly which object the worker was "preparing" when it failed. Recommended Solutions

Solution A: Exclude StatisticsIn many cases, the crash occurs while Data Pump is trying to recalculate or import optimizer statistics. Add EXCLUDE=STATISTICS to your IMPDP command. Add EXCLUDE=STATISTICS to your IMPDP command

ALTER SYSTEM SET "_disable_asynch_sampling"=TRUE; (Consult with a DBA before changing hidden parameters). Summary Checklist

Short-term remediation steps

| 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 |

To help me narrow down the specific fix for your environment, could you tell me: What is your (e.g., 19.3)? Are you importing into a schema that already contains data ? According to Oracle’s official documentation

Identify the table that fails (e.g., SCOTT.DATA_TABLE ) and exclude it:

@?/rdbms/admin/utlrp.sql

The error 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