There are certain processes that are considered a best practice when you optimize a process search.
A database administrator should create indexes that can further accelerate the inbox queries. Consideration should be given to which business data variables are used in any Inbox query constraints, how they are used, and the type and distribution of data for those variables. Regardless of whether you create any additional indexes, make sure that you recompute the schema statistics for the database after you are finished loading the data to get the fullest optimization performance.