The application and the database are in different regions, since each connection setup would otherwise pay the cross-region latency cost.

The database server has very few CPU cores, since pooled connections share processing resources more efficiently than independent connections.

The application uses a document database rather than a relational database, since document databases handle pooled connections more efficiently.

The application makes only a small number of database queries per day, since each saved connection setup is a noticeable share of the total work.