We have consulted with our database administrators, who have suggested adding one or more indexes to UIM database tables to improve query performance.
Is it acceptable to add our own indexes and will UIM make use of them?
Technically, this is not up to UIM - the underlying database (SQL, Oracle, MySQL) server ultimately makes decisions about query optimizations based on which indexes are appropriate; our queries intentionally do not specify the use of specific indexes but rather we rely on the database server's optimization to make such decisions.
Therefore, the answer to this question is ultimately "Yes" - UIM will make use of additional indexes added by your DBA's (because the SQL server will.)