Can someone shed some extra light about the point re: reducing the number of requests to the DB for a dynamic page. When left unoptimized, Rails (and a lot of other frameworks) often result in 100 DB queries for a page.
One obvious way around this is to ensure the DB joins are done correctly. But the article mentions batching/grouping up the requests. How does that work?
Check out the :include parameter to find method calls in the ActiveRecord documentation.
Say you have 30 blog posts, and your views reference associations to the blog post's owners. Well, views are dumb and if you call post.user on each one within a loop, you end up calling User.find 30 times.
But if you do Post.find(..., :include => [:user]), Rails will know to eager load all users -- and User.find never gets called 10 times.
One obvious way around this is to ensure the DB joins are done correctly. But the article mentions batching/grouping up the requests. How does that work?