Chapter 16. Basic performance enhancements
This chapter covers
- Implementing pagination for resources with the Kaminari gem
- Improving database query speeds with Active Record features
- Caching pages and fragments of pages
- Using the Delayed Job gem with background workers
When an application is written, it may be done in such a way that it will not perform ideally. A common situation is that an application with a small database will perform quickly because there is less data to retrieve, but starts to slow as the database grows larger. This problem can be fixed in many different ways.
The first way is to limit the amount of data retrieved in any one call to a fixed limit, a process known as pagination. At the moment, for example, you’re not limiting the number of tickets shown in the show action of the ProjectsController. The more tickets that get added to a project, the slower the page that shows this data is going to perform because it will have to retrieve more data from the database and render it out to the page. By breaking the data down into a set of pages, you can show 50 tickets per page. This will lessen the load on your database, but not completely eliminate it. That would only be possible if you were to run no queries at all. You could do exactly that if you cached the output of the page, or even just the part of the page that showed the list of tickets.