Question

You maintain a Cosmos DB container named 'orders' partitioned by /customerId. A reporting dashboard runs the query SELECT VALUE MAX(c.orderTotal) FROM c to display the single largest order value across all customers. The dashboard runs this query once every few seconds and RU consumption has become a concern. Which approach reduces the RU cost of repeatedly obtaining this value most effectively?

Accepted Answer

Maintain a separate 'stats' item updated via the change feed that stores the running maximum orderTotal, and issue a point read against it from the dashboard.

Answer

Add an ORDER BY c.orderTotal DESC clause with a TOP 1 to the existing query so the engine can use the index more efficiently.

Answer

Enable autoscale on the container so the query automatically gets more RU/s when the dashboard runs.

Answer

Switch the SDK from gateway mode to direct mode so the aggregate query bypasses cross-partition fan-out.