Λεωνίδας Μηλώσης - Optimize – optimize – optimize: Caring for performance of your WordPress plugin or website

Why performance is important and how a WordPress developer can identify and implement quick wins to optimize it. Learn how you can use object cache to improve performance and how to let AI help you with making code faster.

Transcript

1. Optimize - optimize - optimize Caring for performance of your WordPress plugin or website
2. Leonidas Milosis Based in Thessaloniki, I'm a plugin developer at Yoast with more than a decade of experience in the WordPress ecosystem. I am passionate about backend performance and grateful that I can work on products that reach millions of users world-wide. Plugin developer at Yoast
3. But first, why?
4. "Web performance — and its associated best practices—are vital for your website visitors to have a good experience." - The Mozilla Foundation - Why? - Good UX https://developer.mozilla.org/en-US/docs/Learn_web_development/Extensions/Performance/why_web_performance
5. Good UX = Better conversion rates
6. According to Amazon, every 100ms of latency cost Amazon 1% of their sales. According to Walmart, speeding up pages by 100ms affects incremental revenue by up to 1%. According to Financial Times, 1-second delay in page speed leads to a 4.6% drop in article views. Better performance = Better conversion rates https://nitropack.io/blog/post/web-performance-matters-case-studies
7. "Google's core ranking systems look to reward content that provides a good page experience." - Google Good UX = Better SEO developers.google.com/search/docs/appearance/page-experience
8. "We highly recommend site owners achieve good Core Web Vitals for success with Search and to ensure a great user experience generally. This, along with other page experience aspects, aligns with what our core ranking systems seek to reward." Good UX = Better SEO https://developers.google.com/search/docs/appearance/core-web-vitals
9. Core Web Vitals metrics https://developers.google.com/search/docs/appearance/core-web-vitals Largest Contentful Paint (LCP): Measures loading performance. Interaction To Next Paint (INP): Measures responsiveness. Cumulative Layout Shift (CLS): Measures visual stability.
10. Core Web Vitals metrics https://developers.google.com/search/docs/appearance/core-web-vitals Largest Contentful Paint (LCP): Measures loading performance. Interaction To Next Paint (INP): Measures responsiveness. Cumulative Layout Shift (CLS): Measures visual stability.
11. "Good performance is an asset. Bad performance is a liability." https://developer.mozilla.org/en-US/docs/Learn_web_development/Extensions/Performance/why_web_performance
12. Where are the quick wins?
13. Cacheable database operations (are there queries that we can cache?)​ Where are the quick wins?
14. Enter WP_Object_Cache developer.wordpress.org/reference/classes/wp_object_cache WP_Object_Cache The WordPress Object Cache is used to save trips to the database. It stores all the cache data to memory and makes the cache contents available by using a key, which is used to name and later retrieve the cache contents. By default, the object cache is non-persistent. This means that data stored in the cache resides in memory only and only for the duration of the request. Cached data will not be stored persistently across page loads unless you install a persistent caching plugin.
15. Persistent Object Cache developer.wordpress.org/reference/classes/wp_object_cache Plugins that you can use: • Redis Object Cache provides a persistent backend for the WordPress object cache. A Redis server is required. Or even easier: • Docket Cache uses php’s built-in opcode cache mechanism to provide a persistent object cache. • SQLite Object Cache provides a persistent backend using the SQLite database engine. The SQLite3 extension for PHP is required.
16. WP_Object_Cache • wp_cache_get( int|string $key, string $group = '', bool $force = false, bool $found = null ): mixed|false Retrieves the cache contents from the cache by key and group
17. WP_Object_Cache • wp_cache_set( int|string $key, mixed $data, string $group = '', int $expire ): bool Saves the data to the cache
18. WP_Object_Cache • wp_cache_delete( int|string $key, string $group = '' ): bool Removes the cache contents matching key and group
19. WP_Object_Cache • wp_cache_flush_group( string $group ): bool Removes all cache items in a group, if the object cache implementation supports it
20. Should I cache that query?
21. Should I cache that query? When should I?
22. Should I cache that query? When should I? When it's computationally expensive (it's on large tables, or it's a nested query, etc.) When it's clear when to invalidate the cache, to avoid serving stale data
23. Query Monitor is your friend wordpress.org/plugins/query-monitor
24. Query Monitor is your friend
25. Real-world example
28. Let's cache that
30. Getting the cache
31. Getting the cache Setting the cache
32. What about cache invalidation?
33. Flushing the cache
34. After the first page load and until the cache is flushed
35. Cacheable database operations (are there queries that we can cache?) Where are the quick wins?
36. Cacheable database operations (are there queries that we can cache?) Recurring operations (can we optimize code that runs on every page load?) Where are the quick wins?
37. Candidate to be optimized Code that compares two arrays to see if they are the same Runs frequently If it's not optimized, effects are compounded What if a simple strict comparison is faster?
38. Potential optimization VS
39. Let's use AI to optimize code
40. Add code to Copilot agent
41. Ask Copilot to optimize code
42. Ask Copilot to optimize code
43. Verify the optimization
44. Verify the optimization Run the snippet in 3v4l.org
45. Verify the optimization Original approach Optimized approach
46. Verify the optimization Big enough sample
47. Verify the optimization Make some arrays different
48. Verify the optimization Original approach Optimized approach
49. Verify the optimization
50. Verify the optimization Looks like Copilot was right
51. Verify the optimization Let's take a look again
52. Asking Microsoft Copilot
53. Verify the optimization Run the snippet in 3v4l.org again
54. Verify the optimization
55. Verify the optimization Check the new results
56. Verify the optimization Even more confident about the optimization
57. Cacheable database operations (are there queries that we can cache?) Recurring operations (can we optimize code that runs on every page load?) Where are the quick wins?
58. https://x.com/LeonidasMilosis Leonidas Milosis Find me and come talk to me!