Azure SQL Database Troubleshooting

Troubleshooting Azure SQL Database

This section provides guidance on diagnosing and resolving common issues encountered with Azure SQL Database.

Common Problem Areas

• Connectivity Issues: Problems connecting to your Azure SQL Database instance.
• Performance Degradation: Slow query execution, high CPU, or low DTU/vCore utilization.
• Error Messages: Understanding and resolving specific error codes and messages.
• Availability and Failover: Issues related to database availability and automatic failover.
• Resource Governance: Problems with throttling or exceeding resource limits.

Connectivity Troubleshooting

1. Firewall Rules

Ensure that your client IP address is allowed through the Azure SQL Database firewall.

1. Navigate to your Azure SQL server in the Azure portal.
2. Under "Security", select "Networking".
3. Verify that "Allow Azure services and resources to access this server" is enabled if applicable, and that your client IP is listed or a suitable IP range is configured.

2. Connection Strings

Double-check your connection string for accuracy, especially the server name, database name, username, and password.

Example connection string:

Server=tcp:your_server_name.database.windows.net,1433;Initial Catalog=your_database_name;Persist Security Info=False;User ID=your_user_name;Password=your_password;MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;

3. DNS Resolution

Ensure that your network can resolve the Azure SQL Database server name. Try pinging or using nslookup.

Performance Troubleshooting

1. Identify Bottlenecks

Use Azure SQL Database tools to diagnose performance issues:

• Azure Portal: Monitor CPU, Data I/O, Log I/O, and Storage usage on the "Overview" and "Performance" blades.
• Query Performance Insight: Identify top-consuming queries.
• Dynamic Management Views (DMVs): Use DMVs like sys.dm_exec_requests, sys.dm_exec_query_stats, and sys.dm_db_resource_stats for detailed insights.

2. Optimize Queries

Inefficient queries are a common cause of performance problems.

• Analyze execution plans.
• Ensure proper indexing.
• Rewrite queries to be more efficient.
• Consider using Query Store.

3. Resource Scaling

If your database is consistently hitting resource limits (DTUs/vCores, IOPS, throughput), consider scaling up your service tier or compute size.

Common Error Codes

Error 40613: Database is currently unavailable

This error typically indicates that the database is in a transitional state or experiencing an issue. Try reconnecting. If the problem persists, check the Azure Service Health dashboard or contact Azure Support.

Error 18456: Login failed for user

This usually means the login credentials are incorrect or the user does not have permission to connect. Verify the username, password, and ensure the server firewall allows access from your IP address.

Monitoring and Diagnostics

Proactive monitoring is key to preventing and quickly resolving issues.

• Configure alerts in Azure Monitor for key performance metrics and errors.
• Utilize Azure SQL Database diagnostics logs for detailed event tracing.
• Implement regular performance reviews using Query Performance Insight and DMVs.