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

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

impdp ... PARALLEL=1 # or match CPU cores For those encountering this error in the wild,

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 For those encountering this error in the wild,

The schema being imported contains invalid spatial indexes, functional indexes, or complex constraints that fail during the "prepare" phase. For those encountering this error in the wild,

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

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