https://pawelurbanek.com/rails-active-record-caching

Caching might seem a perfect solution to speed up slow database queries. However, caching in Rails apps can be easily misused, leading to poor maintainability or even slower performance than without it. In this blog post, I’ll discuss the common pitfalls of caching SQL queries in Rails apps. I’ll also describe my toolkit for assessing the cacheability of database queries and techniques for reducing the cost of caching infrastructure.