tracking object changes in Vertica

There are two types of objects whose last modified time is recorded.

In the system table PROJECTION_DELETE_CONCERNS: 

Lists projections whose design may cause performance issues when deleting data. This table is generated by calling the EVALUATE_DELETE_PERFORMANCE function.

In the system table COMMENTS, which contains information about comments associated with objects in the database.

Hope that helps,

Sarah

Although the retention may be limited, you may want to try looking in query_requests:

select start_timestamp, user_name, request from query_requests where request_type = 'DDL';