In the Rails Guides about caching there is an explanation:
However, it’s important to note that query caches are created at the start of an action and destroyed at the end of that action and thus persist only for the duration of the action. If you’d like to store query results in a more persistent fashion, you can in Rails by using low level caching.
So what is that "low level caching"? Is it explained in Guides?
Actually, I don’t think it is. It might be and I’m just not aware of it. Rails has several layers of caching. Page, Action, and fragment caching are high level caches. There’s a general cache, Rails.cache, that exists and you can write to it directly at a lower level. Typically, this is done in a model and the mainstay of low level caching is the Rails.cache.fetch method. You can also initiate your own caches. There might be places on the web that document it. It’s pretty well documented in The Rails 4 Way but that’s a book you would need to purchase.
check this article out. http://robotmay.com/post/23161612605/everyone-should-be-using-low-level-caching?20dba200
i hope you find it useful