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Monitoring SQL Server Analysis Services

Effective monitoring of SQL Server Analysis Services (SSAS) is crucial for ensuring optimal performance, availability, and efficient resource utilization. This document outlines key metrics, tools, and best practices for monitoring your SSAS environment.

Key Areas to Monitor

Performance Metrics

  • Query Performance: Latency of MDX and DAX queries, number of queries executed per second, query throughput.
  • CPU Utilization: Percentage of CPU used by SSAS processes. High CPU can indicate inefficient queries or resource constraints.
  • Memory Usage: Amount of RAM used by SSAS, buffer pool usage, cache hit ratios.
  • Disk I/O: Read and write operations per second for SSAS data and log files.
  • Network Traffic: Bandwidth usage between SSAS and clients.

Availability and Health

  • Service Status: Ensure the SSAS service is running.
  • Error Logs: Regularly review SSAS error logs for any critical issues or recurring warnings.
  • Cube Processing Status: Monitor the success and duration of cube processing jobs.
  • Session Management: Track active user sessions and their resource consumption.

Resource Consumption

  • Connection Counts: Monitor the number of concurrent connections to identify potential bottlenecks.
  • Locking and Blocking: Identify and resolve any lock contention issues.
  • Query Execution Plans: Analyze plans for complex or slow-running queries.

Tools for Monitoring SSAS

SQL Server Management Studio (SSMS)

SSMS provides essential tools for monitoring SSAS:

  • Activity Monitor: Offers real-time insights into processes, resource usage, and locks.
  • Performance Dashboard: Provides a high-level overview of server performance.
  • SQL Server Profiler (Deprecated but still usable for some scenarios): Can capture detailed event information for troubleshooting. Use Extended Events for newer versions.
  • Extended Events: A powerful and flexible event tracing system for capturing specific events.
Note: While SQL Server Profiler is still available, Microsoft recommends using Extended Events for monitoring in newer versions of SQL Server.

Windows Performance Monitor (PerfMon)

PerfMon allows you to collect and analyze performance data using SSAS-specific counters:

  • SSAS General: Counters like Cubes, Dimensions, Measure Groups.
  • SSAS Caching: Counters like Cache Hit Ratio, Cache Entries.
  • SSAS Query: Counters like Queries/sec, Query Response Time.

Example PerfMon Counters for SSAS:

\Microsoft Analysis Services 15.0\General\Cubes
\Microsoft Analysis Services 15.0\Caching\Cache Hit Ratio
\Microsoft Analysis Services 15.0\Query\Queries/sec

Dynamic Management Views (DMVs)

SSAS exposes DMVs that provide detailed information about the server's state. You can query these using SQL or MDX.

Example DMV for active queries:

SELECT * FROM $System.Discover_Connections WHERE SessionID IS NOT NULL

Example DMV for query statistics (using SQL in SSMS):

SELECT * FROM sys.dm_exec_requests

Third-Party Monitoring Tools

Various third-party tools offer advanced features for SSAS monitoring, including dashboards, alerting, and historical data analysis.

Best Practices for Monitoring

  • Establish Baselines: Understand your typical performance metrics during normal operation to easily identify anomalies.
  • Set Up Alerts: Configure alerts for critical thresholds (e.g., high CPU, low cache hit ratio, failed processes) to proactively address issues.
  • Regularly Review Logs: Don't just set up alerts; periodically review SSAS error logs and Windows event logs.
  • Monitor Cube Processing: Ensure that scheduled cube processing jobs are completing successfully and within expected timeframes.
  • Track User Activity: Monitor active sessions and query load, especially during peak business hours.
  • Automate Monitoring Tasks: Use scripts or monitoring tools to automate data collection and reporting.
Important: Monitoring is not a one-time task. It requires continuous attention and adaptation as your SSAS environment and usage patterns evolve.

Troubleshooting Common Issues

Slow Queries

Investigate using query execution plans, DMV analysis, and by examining the complexity of MDX/DAX statements.

High Resource Consumption

Analyze CPU, memory, and disk I/O using PerfMon and SSMS. Identify processes or queries consuming excessive resources.

Cube Processing Failures

Review SSAS logs and trace file output for specific error messages. Check data sources, permissions, and the integrity of the model.

By implementing a robust monitoring strategy, you can maintain a healthy and performant SQL Server Analysis Services environment, ensuring a smooth experience for your users and business intelligence applications.