What is N+1 Query: Typical Example, Debugbar and Eager Loading

The N+1 query problem is, from my experience, the number one reason for performance issues in Laravel applications. It occurs when developers unintentionally run too many SQL queries under the hood, particularly when not properly loading relationships.

A Simple Example

Let's consider a common scenario: you want to display a table of posts, where each post belongs to an author. You want to show:

• Post title
• Author's name
• Author's email

In your controller, you might write something like this:

$posts = Post::all();

Then in your Blade template:

@foreach($posts as $post)
    <tr>
        <td>{{ $post->title }}</td>
        <td>{{ $post->user->name }}</td>
        <td>{{ $post->user->email }}</td>
    </tr>
@endforeach

This code looks logical, but it causes a serious performance issue. Why? Because $post->user doesn't automatically load the user data when...