Rails performance optimisation tips

Transcript

1. Classic Rails performance optimisation tips Alessandro Lepore
2. “Please make the site faster” - Any client
3. “Ruby is slow” - Anyone
4. “This is actually fun!” - Alessandro
5. Backend
6. Measure!
7. Measure!
8. DB is fast, Ruby is slow • SQL is awesome • SQL is complex • pluck instead of map • order instead of sort_by • any? instead of present? • size instead of count or length • find_each instead of all • select to limit fields • Avoid collection.to_a • N+1 queries are not always bad
9. N+1 queries are not always bad
10. Useless data is always bad
11. Tips • Measure • Avoid mistakes • Cache all the things! • Use recent Ruby versions • Try optimised gems (fast_blank, fast_jsonapi, concurrent-ruby-ext etc.) • Know your language (GC, Heap, Constant cache etc.) • Concurrency / background jobs • Ruby fine tuning (ENV vars tweaking, alternative malloc) • Also DevOp
12. Frontend
13. Measure! • PageSpeed • YSlow • Speedcurve • Chrome DevTools • Lots of other tools
14. Tips • Limit response size, optimise images • Defer Javascripts • All those things that Rails is already doing ◦ Single file, minify, compress, hash etc. • HTTP headers • Limit connections • Split critical CSS • Limit or async web fonts • Use a CDN • Try new technologies: HTTP/2, WebP...