MySQL stuck restarting - now resolved.

Hi Brad Ashton,

There are several potential reasons why an Azure Database for MySQL – Flexible Server may become stuck in a "restarting" state. One common scenario occurs when a restart is triggered during periods of high workload. If the server is actively processing queries or handling a large number of concurrent connections, a restart may not complete successfully and can leave the server in an unresponsive state.

Another contributing factor is making parameter changes during active usage. It's crucial to ensure that the server is under minimal or no load before applying any configuration updates, as doing so during peak times can cause the restart process to hang. Additionally, resource saturation, such as the server reaching its CPU or storage limits, may result in failed restart attempts and cause the server to remain stuck in the restarting state.

To mitigate these issues, it's important to choose a compute tier that aligns with your business requirements and workload characteristics:

Burstable Tier: Best suited for workloads that do not consistently require full CPU performance. Ideal for development, testing, or lightweight applications.

General Purpose Tier: Designed for most business workloads that need a balanced mix of compute and memory with scalable I/O throughput. Suitable for hosting web and mobile apps, as well as typical enterprise applications.

Business Critical Tier: Intended for high-performance workloads requiring in-memory speed and high concurrency. Ideal for real-time data processing, financial systems, and performance-intensive transactional or analytical applications.