3.3 Azure Database for PostgreSQL/MySQL/MariaDB

Managed Open-Source Databases on Azure

Quick Answer: Azure provides fully managed services for the most popular open-source relational engines: Azure Database for PostgreSQL and Azure Database for MySQL. The current deployment option for both is Flexible Server. The older Single Server option has been retired (PostgreSQL on 28 March 2025, MySQL on 16 September 2024), and the standalone Azure Database for MariaDB service was retired on 19 September 2024 — Microsoft directs customers to migrate to Azure Database for MySQL Flexible Server.

These services are not the same as Azure SQL Database. Azure SQL Database runs the Microsoft SQL Server engine and uses Microsoft's T-SQL dialect. PostgreSQL and MySQL are independent open-source engines with their own SQL dialects, drivers, extensions, and tooling. Azure manages the host, patches the engine, and provides backups and high availability, but applications connect using standard PostgreSQL or MySQL libraries.

Azure Database for PostgreSQL

Azure Database for PostgreSQL comes in two deployment options that you should know for the exam:

• Flexible Server (current) — A single-server PaaS deployment that supports stop/start, zone-redundant high availability, burstable and memory-optimized compute, custom maintenance windows, and a wider set of server parameters. It is the recommended option for new workloads.
• Hyperscale (Citus) — The older name for distributed PostgreSQL on Azure. This deployment option was rebranded and is now a separate product called Azure Cosmos DB for PostgreSQL, covered in section 3.4.

The legacy Single Server deployment option for PostgreSQL was retired on 28 March 2025. New databases cannot be created on Single Server, and existing customers have been migrated.

Flexible Server Highlights

Azure Database for MySQL

Azure Database for MySQL Flexible Server is the current option for MySQL workloads. Like its PostgreSQL counterpart it offers stop/start, zone-redundant HA, burstable compute, and customizable maintenance windows. MySQL Single Server was retired on 16 September 2024.

Typical use cases include WordPress and other PHP-based applications, mobile backends, and any app already targeting MySQL where you want a managed service instead of self-hosting on a VM.

Azure Database for MariaDB Retirement

Azure Database for MariaDB reached end of life on 19 September 2024. The service is no longer available for new deployments. Microsoft's recommended migration path is Azure Database for MySQL Flexible Server, which is wire-compatible with most MariaDB clients and drivers. For the DP-900 exam, remember:

• MariaDB is no longer a Microsoft-managed offering on Azure.
• The migration target is Azure Database for MySQL Flexible Server, not Azure SQL Database.
• If a question lists MariaDB as a current managed service, treat it as outdated.

How These Differ from Azure SQL Database

In short: pick the managed open-source service when your application is already written for PostgreSQL or MySQL, and you want Azure to handle backups, patching, and HA without changing the engine.

Why Microsoft Standardized on Flexible Server

The older Single Server architecture separated compute and storage across a gateway tier, which simplified Microsoft's operations but limited customer control over networking, maintenance timing, and cost. Flexible Server was built to address exactly those gaps: it places the database engine and storage together for lower latency, supports VNet integration for private networking, lets you choose the exact maintenance window, and adds stop/start so non-production databases stop billing compute overnight. This is why every new deployment uses Flexible Server and why the exam treats Single Server as legacy.

Compute Tiers in Flexible Server

Recognizing the Burstable tier is a common exam point: it is the right answer for a small, intermittently used database where cost matters more than sustained throughput, because it banks CPU credits during idle time and spends them during short spikes.

High Availability and Backups

Flexible Server offers zone-redundant HA (a hot standby in a different availability zone with automatic failover) and same-zone HA (a standby in the same zone for faster, lower-cost failover without zone protection). Automated backups support point-in-time restore, and you can configure geo-redundant backup for regional disaster recovery. These map conceptually to the same durability ideas as Azure SQL Database, but they are configured per the open-source service.

Reading a PostgreSQL/MySQL Question

The exam tells you which managed open-source service to pick mainly by the application's existing engine. "A Django app on PostgreSQL," "a LAMP/WordPress site on MySQL," or "a Node app already using MySQL" all point to the matching Flexible Server. If the prompt mentions MariaDB as a current service, treat it as outdated and choose MySQL Flexible Server as the migration target. If the prompt mentions the SQL Server engine or T-SQL, it is the Azure SQL family instead — the open-source services do not run T-SQL or the SQL Server engine.