Ruby Performance Optimization

Make ActionView Faster

It’s not unusual for template rendering to take longer than controller code. But you may think that you can’t do much to speed it up. Most templates are just a collection of calls to rendering helper functions that you didn’t write and can’t really optimize—except when they’re called in a loop.

Rendering is basically a string manipulation. As we already know, that takes both CPU time and memory. In a loop we multiply the effect of what is already slow. So every time you iterate over a large dataset in a template, see whether you can optimize it.

Rails template rendering has performance characteristics similar to Ruby iterators. It’s fine to do just about anything, until you render partials in a loop. There are two ...