Pagy VS bullet

Now, let's dive into the pagination part of this post: setting up Pagy for handling pagination in our Rails application. If you haven't included the Pagy gem in your project, you'll need to add it manually. Here's how you can do it:

Several gems are available for pagination in Rails, but the Pagy gem is one of the most popular and efficient. It is a fast and lightweight library that provides a simple and flexible API. In this article, we’ll explore how to use it to implement pagination in Rails.

> Am I understanding correctly that there’s a significant difference in performance between using a ViewComponent + a partial vs. a ViewComponent which renders html via a tag - from inside the component?

I don't think there will be much difference at all in everyday use, but some libraries that value performance don't avoid templates for that reason, Pagy for example.

https://github.com/ddnexus/pagy

Personally I omit them in my projects whenever we want to customise attributes, I hate seeing stuff like this in templates:

    
Some header

The next step was about backporting the templates, adding Pagy gem for handling pagination and creating the controller. I was then able to show the listings with the models, but the filtering was not working.

On the backend, we'll need a few tools. Apart from the classics (ActiveRecord scopes and the pg_search gem), you’ll see how the (yet officially unreleased but production-tested) all_futures gem, built by SR authors, will act as an ideal ephemeral object to temporarily store our filter params and host our search logic. Finally, we’ll use pagy for pagination duties.

Pagination

In our application, we will use Pagy to implement pagination. Let’s install Pagy now, following along with the Pagy quick start guide.

For pagination I tend not to use gems like pagy or kaminari, instead implement this functionality just using limit and offset.

Kaminari hooks onto ActiveRecord associations and makes it super easy to page them. Pagy is another option that seems to have a solid API but I haven't tried it yet.

But how is this implemented? Well, if you use pagination in your index methods with gems like pagy, kaminari or will_paginate you will find that the same idea is happening here, they are using the power of SQL's LIMIT and OFFSET to fetch only a portion of the data each time. So in the 1 million users example, find_each will perform 1000 thousand queries with a limit of 1000 while changing the offset properly so we don't miss any record.

Rails has Bullet[0] to help identify and warn you against N+1

Does Django have anything active? Quick search revealed nplusone[1] but its been dead since 2018.

[0] https://github.com/flyerhzm/bullet

[1] https://github.com/jmcarp/nplusone

Without seeing more of the app, it's tough to say for certain, but one gem you might find helpful is the [bullet](https://github.com/flyerhzm/bullet) gem -- set this up in the app then start browsing around the app in development. If you have any N+1 queries or other minor optimizations that could be done it will inform you about them.

Getting rid of N+1 queries - This can help improve the speed of an app. The Bullet or Prosopite gems can give a lending hand here. The N+1 Dilemma — Bullet or Prosopite? entails a brief comparison of both.

There's a Ruby gem called Bullet that identifies and warns developers about N+1 problems. You can also have it fail tests if detected.

I don't know if the approach is possible with every ORM or if it's just leveraging some Ruby perks, but I can't think of a good reason why you wouldn't use the equivalent everywhere.

https://github.com/flyerhzm/bullet

You might consider adding the bullet gem as a development requirement and see what it tells you, it's generally pretty good at spotting n-queries and letting you know how to fix them.

As a Rails developer, recently I found Bullet [0] which helps massively in dealing with eager loading. For some reason I expected the framework to manage this sort of thing for me, even when Rails actually does a ton out of the box already. Only while refactoring I picked up on queries dragging performance. Oh well...

[0] https://github.com/flyerhzm/bullet

This is good advice, it'll likely pick out some glaring issues right away. I would generally recommend looking at DB queries here too and recommend Bullet, but most software like DataDog, AppSignal etc will often also point N+1 and issues like it out.

In order to find all those N + 1 queries that are slowing down in your application, the community recommends using the Bullet gem.