Question

An e-commerce platform stores individual order documents in a Cosmos DB container partitioned by /customerId. The analytics team needs a separate 'customerSummary' container that maintains a running total of each customer's lifetime spend and order count, updated within seconds of any new order. The solution must scale automatically and avoid expensive periodic full-container scans. Which approach best meets these requirements?

Accepted Answer

Deploy an Azure Function with a Cosmos DB trigger bound to the orders container's change feed that reads each changed order and upserts the aggregated totals into the customerSummary container.

Answer

Schedule a timer-triggered Azure Function that runs a cross-partition GROUP BY query over the entire orders container every minute and rewrites the customerSummary container.

Answer

Enable analytical store on the orders container and query it with Azure Synapse Link to compute the aggregates on demand for the summary.

Answer

Create a post-trigger on the orders container that recomputes each customer's totals by querying all their orders whenever a new order is inserted.