There are two aspects to this question:
1.) regaining space for re-usability (new incidents, etc,) & 2.) actual database file size reduction.
1.) regaining space for re-usability (new incidents, etc,):
Re-gaining file is simple
- you delete incidents and all data associated with it from Enfoce UI.
- bydefault, at mid-night the actual deletion from the Oracle Database takes place.
You can see the status on the System > Incident Data > Incident Deletion.
- Once deletion task run is done, you should be able to re-use all that space you regained.
- This can be validated by several scripts/sqlplus commands where actual free space would be visible
2.) actual database file size reduction
After performing incident deletion, and validating deletion under System > Incident Data > Incident Deletion you are required to perform a complete DB upload reload process. Basically create a new DB file. The standard way DBAs do this is normally copy all tables to a different temp database and recopy it back to the original file. This releases DB space.