Question

You maintain a Cosmos DB for NoSQL container named 'Orders' partitioned on '/customerId'. A reporting dashboard runs the query: SELECT * FROM c WHERE c.status = 'Shipped' AND c.region = 'EU'. Neither 'status' nor 'region' is the partition key, and the container spans 40 physical partitions. Users complain the query consumes excessive RUs. Which explanation and remediation is most accurate?

Accepted Answer

The query is a cross-partition (fan-out) query that must be evaluated on all physical partitions; adding a composite index on (status, region) or restructuring to include customerId in the filter reduces the cost.

Answer

The query is a point read that is inefficient because status is not indexed; enabling the default indexing policy will convert it to a single-partition lookup.

Answer

The high cost is caused by the gateway connection mode; switching to direct mode eliminates the fan-out entirely.

Answer

The query already targets a single partition because status equals a constant; the RU cost is unrelated to partitioning and can only be lowered by increasing provisioned throughput.