A company runs a large-scale write-intensive application that requires a horizontally scalable relational database. They need to distribute data across multiple nodes to handle high write throughput while supporting SQL queries, including joins and transactions. The solution must be fully managed and provide elastic scaling. Which Azure database service should they choose?

Azure SQL Database Hyperscale

Hyperscale separates compute and storage for a large single database but still has a single primary for writes, limiting write scalability.

Azure Cosmos DB

Cosmos DB is a NoSQL database; although it supports SQL querying, it does not provide a relational model with full cross-node join capabilities and transactions.

Azure SQL Managed Instance

SQL Managed Instance is a single instance version of SQL Server in Azure; it does not natively distribute data across multiple nodes for write scaling.

What does this AZ-305 question test?

Read the scenario before looking for a memorised answer.

What is the correct answer to this question?

The correct answer is: Azure Database for PostgreSQL Hyperscale (Citus) — Azure Database for PostgreSQL Hyperscale (Citus) is a fully managed service that horizontally scales across multiple nodes by distributing data (sharding). It supports SQL queries, transactions, and can handle write-intensive workloads by distributing writes across nodes. Azure SQL Database Hyperscale is designed for large single databases but with a single write primary, not multi-node distribution for write-heavy scaling. Azure Cosmos DB is a NoSQL database with SQL API but not a relational database with full support for joins and transactions across partitions. Azure SQL Managed Instance is a single-instance PaaS database with limited scaling options.

What should I do if I get this AZ-305 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.