The Queries selection provides the ability to determine the default read preference for queries against this data model.
Primary Prefered :
The primary preferred read preference ensures consistent and up-to-date data but allows reading potentially stale data from a secondary in the event of a transient outage of the primary server. This is the default read preference.
Secondary :
The secondary read preference shifts read-heavy workloads to less-used resources, but queries may return stale data. In the event of an outage of all secondary servers, the query will fail. This read preference is recommended for ETL and reporting workloads
