Question

A logistics company runs a globally distributed Cosmos DB account with multi-region writes enabled across four regions. Their shipment-tracking documents are frequently updated concurrently in different regions, and business rules require that when two updates conflict, the conflicting values must be merged into a single document by keeping the highest recorded package weight and concatenating the two status notes. Simple last-writer-wins behavior is not acceptable. Which conflict resolution configuration should they implement?

Accepted Answer

Use a Custom conflict resolution policy with a registered merge stored procedure that reads the conflicting versions and produces the merged document.

Answer

Use a Last Writer Wins policy configured on a numeric _ts-based path so the most recent write always prevails.

Answer

Use a Custom conflict resolution policy without registering a stored procedure so conflicts appear in the conflicts feed for the application to resolve, and Cosmos DB automatically merges them.

Answer

Switch the account to Strong consistency so that write conflicts can never occur across regions.