You are designing an application that will aggregate content for users. You need to recommend a database solution for the application. The solution…

Azure Cosmos DB is a globally distributed, multi-model database service designed for low-latency reads and writes. The SQL API allows querying data using familiar SQL syntax. A key feature of Cosmos DB is its native support for multi-region writes (also known as multi-master), which allows applications to write to any of the replicated regions. This configuration provides the highest availability for writes and ensures low-latency operations for users distributed globally, directly meeting all the specified requirements.

B. Azure SQL Database that uses active geo-replication: This configuration provides readable secondary replicas, not a multi-master write capability. All write operations must be directed to the single primary region.

C. Azure SQL Database Hyperscale: Hyperscale is a service tier focused on scaling storage and compute for very large single databases; it does not provide a native multi-master write feature.

D. Azure Database for PostgreSQL: This service uses a primary server for writes and read replicas for scaling read operations. It does not support a multi-master write configuration.

1. Azure Cosmos DB Multi-Region Writes: Microsoft Learn. (2023). Configure multi-region writes in your applications that use Azure Cosmos DB. "With your Azure Cosmos DB account configured for multi-region writes

your applications can be configured to direct their writes to any of the configured regions... This configuration is the best option for the highest availability and lowest latency."

2. Azure Cosmos DB SQL API: Microsoft Learn. (2023). Get started with queries in Azure Cosmos DB for NoSQL. "The API for NoSQL in Azure Cosmos DB supports querying items using SQL (Structured Query Language) as a JSON query language."

3. Azure SQL Database Active Geo-Replication: Microsoft Learn. (2024). Active geo-replication for Azure SQL Database. "Active geo-replication is a feature that allows you to create a continuously synchronized readable secondary database for a primary database... All transactions for the primary database are asynchronously replicated to each of the secondary databases." This confirms a single-primary (write) model.

4. Azure Database for PostgreSQL Read Replicas: Microsoft Learn. (2023). Read replicas in Azure Database for PostgreSQL - Single Server. "The read replica feature allows you to replicate data from an Azure Database for PostgreSQL server to a read-only server." This confirms a single-master model.