Troubleshooting Azure Database for MySQL

This guide provides solutions to common issues and troubleshooting steps for Azure Database for MySQL. Whether you're encountering connection problems, performance bottlenecks, or error messages, this documentation aims to help you resolve them efficiently.

Common Issues and Solutions

Connection Problems

If you're having trouble connecting to your Azure Database for MySQL instance, consider the following:

• Firewall Rules: Ensure that your client IP address is allowed through the server's firewall. You can configure firewall rules in the Azure portal under the server's "Connection security" settings.
• SSL/TLS Configuration: Verify that your application is configured to use SSL/TLS for secure connections.
• Authentication: Double-check your username, password, and hostname.
• VNet Service Endpoints/Private Endpoints: If you're using VNet integration, ensure it's configured correctly and that your application can reach the private IP address.

Performance Bottlenecks

Slow query performance or general sluggishness can stem from various factors. Here are some areas to investigate:

• Query Optimization: Analyze your queries using tools like `EXPLAIN` to identify inefficient execution plans.
• Indexing: Ensure appropriate indexes are created for frequently queried columns.
• Server Parameters: Review and tune MySQL server parameters (e.g., `innodb_buffer_pool_size`, `query_cache_size`) based on your workload.
• Resource Utilization: Monitor CPU, memory, and IOPS through Azure Monitor to identify resource constraints. Consider scaling up your compute or storage tiers if necessary.
• Connection Pooling: Implement connection pooling in your application to reduce the overhead of establishing new connections.

Replication Issues

Problems with read replicas or high availability setups can be complex. Common areas to check include:

• Replication Lag: Monitor the replication lag between the primary and replica instances. High lag can indicate network issues or a stressed primary server.
• Replication User Permissions: Verify that the replication user has the necessary privileges on both the primary and replica.
• Binary Log Configuration: Ensure `binlog_format` is set correctly (usually `ROW` for Azure Database for MySQL replication).

Error Messages and Codes

Encountering specific error messages? Refer to the common error codes and their explanations:

• Error 1045 (Access denied): Usually due to incorrect credentials or firewall restrictions.
• Error 1005 (Can't create table): Often related to insufficient permissions, disk space, or syntax errors.
• Error 2002 (Can't connect to local MySQL server): This typically indicates a network connectivity issue or that the MySQL server process is not running (less common in managed services).

Diagnostic Tools and Techniques

• Azure Monitor: Provides metrics on server performance, availability, and resource utilization.
• Azure Activity Log: Records operations performed on your Azure resources, useful for tracking changes and potential misconfigurations.
• MySQL Error Logs: While direct access to the MySQL error log file isn't available, Azure provides insights and diagnostic data through the portal.
• `mysqladmin` and `SHOW STATUS` commands: Useful for gathering runtime information about the MySQL server.

Escalating an Issue

If you've exhausted the troubleshooting steps and still need assistance, consider opening a support request with Microsoft Azure. Provide as much detail as possible, including:

• The exact error message(s) you are encountering.
• The time the issue started.
• Steps taken to reproduce the issue.
• Relevant server configurations and application details.