In a recent Business Bloomer Club Slack thread, a WooCommerce site owner sought advice on diagnosing high PHP-FPM resource consumption on their VPS server hosted with Plesk. Despite a relatively moderate traffic load, the site—large in terms of product count and running in multiple languages via WPML—was experiencing high CPU and memory usage, leading the user to suspect the site’s theme and custom functions as potential culprits. They aimed to pinpoint precisely which scripts or functions were consuming excessive resources.
The discussion covered effective tools and strategies for diagnosing server load issues. Advanced Performance Monitoring (APM) solutions like New Relic were recommended as ideal for identifying specific lines of code that may be slowing down the site. Such tools can break down execution times, helping users understand which plugins, scripts, or custom functions are consuming resources.
Diagnosing Resource Consumption with APM
One effective approach suggested was to use an APM solution, such as New Relic, to identify performance bottlenecks. By examining metrics like time spent per function or script, APM tools help determine which elements on the site are resource-heavy. These insights can guide necessary adjustments and enable targeted troubleshooting.
Performance Optimization Steps Taken
The user followed these diagnostic steps to narrow down the issues:
- Switching to a Basic Theme: By temporarily using a default theme, they could assess if the site’s theme was contributing to the load.
- Deactivating Plugins: Disabling all plugins and then reactivating them one by one helped reset cached configurations and determine potential plugin conflicts.
- Server-Timing Headers: Using Server-Timing headers, they benchmarked PHP performance to see how specific functions impacted load times.
Interestingly, after the initial plugin reset and re-enabling all site functions, resource consumption stabilized at a lower level without any additional changes. This raised the possibility that cached data or old configurations could have been causing the initial high load.
Additional Improvements
To further optimize performance, the user implemented Redis caching, significantly reducing database query load and improving resource efficiency. Switching to PHP-FPM over FastCGI also contributed to more efficient PHP processing.
Key Takeaways
- Use APM Tools: Solutions like New Relic provide deep insights into which code or plugins impact performance most.
- Cache and Plugin Management: Sometimes, deactivating and reactivating plugins or adding a Redis cache can reset performance issues.
- Server Configuration: PHP-FPM often provides better resource management than FastCGI, especially on high-load sites.
For WooCommerce users experiencing unexplained resource spikes, these strategies offer a structured approach to diagnosing and optimizing site performance.
