Run Database maintenance
Most databases do not perform a true delete and re-index when objects are deleted. Thus, there will be no real impact on the total size of the database without running database maintenance.
Talend Data Catalog provides a tool to perform database maintenance. There is a script operation named Run database maintenance. This is a system management task which should be scheduled periodically.
Information note
If a large number of models and versions are deleted at once, it may be necessary to execution the Database maintenance operation many times.