How do I access user account details from MetaMatrix repository

Issue

• I have question on finding out whether given user (say user account is abc_app) has accessed / queried metamatrix recently or in the past one year.

We are doing some impact analysis for production upgrade to 5.5.4 on April 23rd so there are few application accounts in our inventory list of account accessing metamatrix but those technical contacts have left the company so we are trying to find out whether that application is still using metamatrix or not.

Does metamatrix stores the user info, queries issued by that user etc in the repository to query ?  If so,  can you please tell me which table has in metamatrix repository has user info logged in when user logs in and queries the metamatrix.