Reason of ORA-00604 - ORA-00904: on online Redefining
Performing online redefinition creates materialized view log on the source table, that is where DML changes are tracked during the redefinition process.

Finishing the online redefinition gracefully (finish_redef_table or abort_redef_table) removes the materialized view log automatically, otherwise it will stay there.

Truncating the table with an existing materialized view works with the following syntax:

truncate table tab1 purge materialized view log;

Or just simply drop the materialized view log before.

Without specifying the above, truncate fails because of a recursive query on SYS.MLOG$, as that table does not have the column CURRENT_SCN (version &lt;= 11.2). It is fixed from 12.1.