MySQL & MariaDB Performance Tuning using Mysqltuner

MySQL and MariaDB are one of the most popular open source relational database management systems. It powers many of the world’s most visited web services and applications. As usage grows, performance tuning becomes essential to optimize MySQL and avoid issues like slow queries.

Mysqltuner is an open source Perl script that helps analyze and tune MySQL performance. It provides configuration and performance recommendations to optimize MySQL. In this comprehensive guide, we will cover:

Overview of mysqltuner

mysqltuner is a Perl script written and maintained by Major Hayden. It connects to MySQL, runs diagnostics, and provides configuration and tuning advice for improved performance.

Key features of mysqltuner include:

• Quickly diagnose MySQL performance issues
• Suggest configuration changes for increased performance
• Recommend hardware upgrades for large installations
• Monitor memory, temporary tables, table cache hit rate, open files, and other metrics
• Estimate growth trends using historical statistics
• Generate a report with all metrics and advice

mysqltuner is easy to use and provides clear, actionable recommendations. It is a valuable tool for MySQL performance monitoring and tuning.

Installing mysqltuner

mysqltuner is a standalone Perl script. To install it:

• Install Perl if it is not already installed:

$ sudo apt install perl

• Download the latest mysqltuner script:

$ wget https://raw.githubusercontent.com/major/MySQLTuner-perl/master/mysqltuner.pl

• Make the script executable:

$ chmod +x mysqltuner.pl

• Optionally rename and move the script:

$ sudo mv mysqltuner.pl /usr/local/bin/mysqltuner

Now mysqltuner is installed and ready to use!

Using mysqltuner for performance tuning

Using mysqltuner is simple. Just run the script with your MySQL credentials:

$ mysqltuner --host localhost --user root --pass password

This will connect to the MySQL server on localhost as the root user, run diagnostics, and print a report.

To save the report to a file:

$ mysqltuner --host localhost --user root --pass password > mysqlreport.txt

Key options include:

• --host⁣ – MySQL hostname
• --user⁣ – MySQL username
• --pass⁣ – MySQL password
• --silent⁣ – Hide progress dots during processing
• --nobad⁣ – Remove bad advice from final report
• --nogood⁣ – Remove good advice from final report
• --forcemem⁣ – Amount of RAM installed in megabytes

Review the report for performance advice and apply the recommendations. Rerun mysqltuner periodically to monitor changes over time.

Interpreting mysqltuner Recommendations

The mysqltuner report contains many metrics and suggestions. Here are some key areas to focus on:

Performance Metrics

• Uptime – How long MySQL has been running uninterrupted. Long uptimes indicate stability.
• Total buffers – Total memory allocated to cache indexes and tables. Higher is better.
• Open files – Number of open files. Many open files could indicate index issues.
• Table cache hit rate – Look for a high cache hit rate, ideally over 99%. Lower rates indicate tuning needed.

Configuration Suggestions

• Maximum memory usage – Increase if available memory allows to improve performance.
• Key buffer size – Raise if possible to improve index usage.
• Table cache – Increase to avoid file open limits.
• Thread cache size – Raise to avoid thread creation overhead.

Hardware Suggestions

• RAM – Add more RAM if needed to support additional memory buffers.
• CPUs – Reduce CPU load or add cores if CPU utilization is high.
• Storage – Fast storage helps improve I/O performance.

Query Performance

• Slow queries – Tune expensive queries and add indexes where needed.
• Temporary tables – High temporary tables could indicate suboptimal indexes.

Implementing mysqltuner Recommendations

Here are some steps to act on mysqltuner recommendations and tune MySQL performance:

1. Adjust Memory Allocation – If more RAM is available, increase key buffer, query cache size, innodb buffer pool size, and table cache. This allows MySQL to keep more indexes and data in memory.
2. Optimize Slow Queries – Review slow queries, add indexes, and tune expensive joins or subqueries. This greatly improves overall throughput.
3. Improve Indexes – Inspect index usage with tools like EXPLAIN. Add needed indexes and remove unused ones. Pay attention to key buffer size.
4. Concurrency Tuning – Tune thread cache size, max connections, worker threads, and other concurrency settings. Find optimal values.
5. Storage Optimization – Ensure storage subsystem has adequate IOPS and throughput for workload. SSD storage provides huge gains.
6. Server Sizing – Rightsize server resources like CPU cores, RAM, storage as database grows. Monitor growth trends.
7. Configuration Best Practices – Review settings against recommended values like table cache, join buffer size, query cache size, etc.
8. Periodic Review – Rerun mysqltuner every few weeks. Implement additional recommendations as needed.

With diligent tuning guided by mysqltuner, you can optimize MySQL to handle heavy workloads and deliver maximum performance. The key is regularly reviewing metrics and incrementally applying recommendations over time.

MySQLTuner Script Explained

The mysqltuner.pl script is well structured and extensively commented. Let’s walk through the main sections to understand what it does under the hood:

Initial Connection

• Imports modules for database connections, text formatting, statistics
• Processes command line arguments
• Makes database connection using given credentials

Data Collection

• Initializes variables for calculations
• Executes SHOW statements to collect configuration
• Executes queries on INFORMATION_SCHEMA for metrics
• Calculates ratios, hits, misses, totals on metrics

Analysis and Reporting

• Checks metrics against recommended thresholds
• Compares current and previous mysqltuner report if exists
• Prints configuration variables and table metrics
• Makes hardware, configuration, indexing suggestions
• Formats report output and highlights issues

Connection Cleanup

• Closes database connection
• Exits gracefully

This shows the basic flow – connect, gather data, analyze, print report, disconnect. The heavy lifting is done by the data collection and analysis sections. MySQLTuner relies on SHOW commands and INFORMATION_SCHEMA queries to get configuration values and performance metrics.

Ways to Use MySQLTuner

In addition to ad-hoc tuning, here are other good ways to leverage mysqltuner:

Application Testing – Run mysqltuner on development, staging, and production to compare configurations. Fine tune each environment.

New Database Server – Create a baseline report after provisioning a new database server. Use for initial sizing and tuning.

Performance Trends – Execute mysqltuner over time and save reports. Check for trends as database grows.

After Upgrade – How is performance after a MySQL or OS upgrade? Run mysqltuner to verify.

Cloud Migration – Migrating from bare metal to cloud? A mysqltuner report helps rightsize the instance.

Capacity Planning – Planning a storage, memory, or compute expansion? Mysqltuner indicates where resources are needed.

Diagnostics – If MySQL is slow, run mysqltuner to help uncover the bottlenecks.

These examples demonstrate the wide applicability of mysqltuner for various performance monitoring and tuning scenarios.

Alternative Tuning Tools

While mysqltuner is easy to use and full featured, there are other MySQL tuning tools to consider:

• Percona Toolkit – Advanced open source toolkit with pt-mysql-summary and pt-query-digest.
• MySQL Enterprise Monitor – GUI based dashboard for metrics and advisors.
• MySQL Query Analyzer – Track query performance over time.
• EXPLAIN ANALYZE – Optimizer statistics to choose better query plans.
• Performance Schema – Fine grained MySQL performance data.

Mysqltuner makes an excellent starting point due to its ease of use and clear results. Complement it with other tools that provide drilling down capabilities for advanced tuning.

Conclusion

mysqltuner is an invaluable tool for monitoring and tuning MySQL & MariaDB performance. It quickly diagnoses problems and offers clear, actionable suggestions for improvement.

Following mysqltuner’s advice can help resolve or avoid many common MySQL performance pitfalls. It’s an essential tool for any database administrator or application developer using MySQL in production.

Consistent use of mysqltuner and other complementary tools will maximize database efficiency, reduce infrastructure costs, and provide the best experience for applications and their users.