Azure SQL Database Documentation

Monitoring Azure SQL Database

Effective monitoring of your Azure SQL Database is crucial for ensuring optimal performance, availability, and cost-efficiency. Azure provides a rich set of tools and services to help you gain insights into your database's health and activity.

Key Monitoring Areas

• Performance Metrics: Track CPU usage, data IO, log IO, memory consumption, and query latency.
• Availability: Monitor uptime, connection success rates, and potential service disruptions.
• Security: Observe login attempts, auditing events, and vulnerability assessments.
• Resource Utilization: Understand DTU or vCore consumption, storage usage, and network traffic.
• Query Performance: Identify slow-running queries, analyze execution plans, and optimize query efficiency.

Azure Tools for Monitoring

Azure Monitor

Azure Monitor is the foundational service for collecting, analyzing, and acting on telemetry from your Azure and on-premises environments. For Azure SQL Database, it provides:

• Metrics: Real-time and historical performance data accessible via the Azure portal, APIs, and PowerShell.
• Logs: Diagnostic logs and query performance insights, which can be stored in Log Analytics workspaces for detailed analysis.
• Alerts: Proactive notifications based on predefined metric thresholds or log queries.

Common metrics to monitor include:

• cpu_percent: Percentage of compute allocated to the database.
• io_percent: Percentage of Data IO used.
• log_bytes_used: Amount of transaction log space used.
• deadlocks: Number of deadlocks encountered.
• storage_percent: Percentage of allocated storage used.

You can set up alerts for critical thresholds, such as high CPU utilization or low storage space, to prevent performance degradation or outages.

Query Performance Insight

Query Performance Insight provides an intelligent view of your workload's performance. It helps identify the top resource-consuming queries and allows you to analyze them in detail.

• Visualize query execution statistics.
• Drill down into individual query performance.
• Identify and troubleshoot performance bottlenecks.

This tool is invaluable for database administrators and developers looking to optimize their SQL queries.

Dynamic Management Views (DMVs)

DMVs offer real-time operational information about the SQL Server instance. You can query them directly to get detailed insights into various aspects of your database.

Some commonly used DMVs for monitoring include:

• sys.dm_db_resource_stats: Provides information about resource usage for a database in Azure SQL Database.
• sys.dm_exec_query_stats: Returns the average execution statistics for cached execution plans.
• sys.dm_exec_sessions: Information about the currently active sessions.

Example DMV query to find the top 5 most expensive queries:

SELECT TOP 5
    qs.execution_count,
    qs.total_elapsed_time / qs.execution_count AS average_elapsed_time,
    SUBSTRING(st.text, (qs.statement_start_offset/2.0)+1,
        ((CASE qs.statement_end_offset
            WHEN -1 THEN DATALENGTH(st.text)
            ELSE qs.statement_end_offset
         END)-qs.statement_start_offset)/2.0) AS statement_text
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) AS st
ORDER BY qs.total_elapsed_time DESC;
            

Azure SQL Analytics (Log Analytics Solution)

Azure SQL Analytics is a comprehensive solution built on Log Analytics that collects and analyzes telemetry from your Azure SQL databases, SQL Managed Instances, and SQL Servers on Azure VMs. It provides:

• Dashboards for overview and drill-down analysis.
• Performance trend analysis.
• Alerting capabilities.

To use Azure SQL Analytics, you typically need to configure diagnostic settings on your SQL resources to send logs and metrics to a Log Analytics workspace.

Best Practices for Monitoring

• Define Baselines: Understand your database's normal performance characteristics to easily identify anomalies.
• Set Up Alerts: Configure alerts for critical metrics and events to be notified of potential issues before they impact users.
• Regularly Review Performance: Schedule time to review performance dashboards, logs, and query analysis reports.
• Monitor Costs: Keep an eye on resource utilization to ensure you are not over-provisioning and incurring unnecessary costs.
• Use a Combination of Tools: Leverage Azure Monitor, Query Performance Insight, and DMVs for a holistic view of your database health.