ORA-12839: Cannot Modify An Object In Parallel After Modifying It

We need to issue, COMMIT or ROLLBACK, before running that parallel DML query.

SQL> delete /*+ parallel (test) */ from test;

delete /*+ parallel (test) */ from test

*

ERROR at line 1:

ORA-12839: cannot modify an object in parallel after modifying it

SQL> commit;

Commit complete.

SQL> delete /*+ parallel (test) */ from test;

1319795 rows deleted.

Hope it Helps!