Struggling with slow performance in your Laravel application? You’re not alone.

One of the most common causes of sluggish apps is slow database queries — and identifying them early can save you hours of debugging, user complaints, and lost traffic. Fortunately, Laravel makes it easy to log slow queries with just a few lines of code.

In this post, I’ll walk you through a step-by-step approach to detect and log slow queries in Laravel — even if you’re just practicing on dummy data.

🧠 Why Should You Track Slow Queries?

Before diving into code, let’s understand why this matters:

Being able to track and log these queries is a powerful way to take control of performance.

🛠️ Step 1: Enable Query Logging in Laravel

In AppServiceProvider.php, add the following to the boot() method:

use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;

public function boot()
{
    DB::enableQueryLog();

    DB::whenQueryingForLongerThan(1000, function ($connection) {
        Log::warning('⚠️ Long running queries detected:', $connection->getQueryLog());
    });
}

🕐 This logs any query that takes longer than 1000ms (1 second).

You can adjust the threshold as needed — even down to 50ms for dev environments.

🧪 Step 2: Create Dummy Data for Testing

Use a seeder to simulate a real-world dataset:

php artisan make:seeder PostSeeder

In PostSeeder.php:

use App\Models\Post;

public function run()
{
    Post::factory()->count(10000)->create();
}

Run the seeder:

php artisan db:seed --class=PostSeeder

Now your database has enough records to test heavy queries.

⚡ Step 3: Trigger a Slow Query (For Testing)

You can simulate a slow query using a simple route:

use Illuminate\Support\Facades\DB;

Route::get('/slow-query', function () {
    usleep(2000000); // 2 seconds delay (in microseconds)
    return DB::table('posts')->limit(1000)->get();
});

Or if you’re using MySQL, try:

return DB::select('SELECT SLEEP(2), title FROM posts LIMIT 1');

This will create a delay long enough to trigger the logging.

📂 Step 4: Check the Logs

Open this file:

storage/logs/laravel.log

And you’ll see something like:

[2025-04-04 14:15:22] local.WARNING: ⚠️ Long running queries detected: [...]

Boom! You’ve just caught a slow query.

🔐 Bonus: Log Full SQL with Bindings

Want to see exact SQL statements?

DB::listen(function ($query) {
    Log::info("SQL: {$query->sql} | Time: {$query->time}ms", $query->bindings);
});

Add this to your AppServiceProvider@boot() during development.

🧩 Real-World Use Cases

✅ Wrap-Up

Laravel gives you the tools — you just need to flip the switch.

By logging long-running queries:

🔔 Next step: Try this on your current project and keep the logs running while developing. You’ll be amazed how quickly you spot patterns.