As a minor but useful new feature, xplan is now able to integrate into its report the DDL of tables (and indexes) referenced by the plan, calling dbms_metadata.get_ddl transparently.

This is mostly useful to get more details about referenced tables’ constraints and partitions definition - to complement their CBO-related statistics that xplan reports about.

This feature can be activated by specifing dbms_metadata=y or dbms_metadata=all (check xplan.sql header of xplan.sql for more informations).

We spoke about xplan in general here.