Eliminate Cache Stampedes with Cache::flexible() and Stale-While-Revalidate

Use Cache::flexible() to serve slightly stale cache values immediately to users while refreshing the cache in the background.

When a heavily requested cached item expires, dozens of simultaneous requests encounter a cache miss at the exact same moment. They all execute the heavy database query simultaneously (known as a "cache stampede" or thundering herd problem), causing database spikes and slow response times.

Cache::flexible() implements the Stale-While-Revalidate caching pattern.

Using Cache::flexible()

use Illuminate\Support\Facades\Cache;

$products = Cache::flexible('homepage_top_products', [5 * 60, 30 * 60], function () {
    // Heavy aggregate database query
    return Product::where('is_featured', true)
        ->withCount('orders')
        ->orderByDesc('orders_count')
        ->limit(10)
        ->get();
});

How It Works

• First 5 minutes (Fresh): Serves cached value immediately from memory.
• Between 5 and 30 minutes (Stale): Serves the existing cached value immediately to the user (0ms delay) and asynchronously triggers the closure in the background to refresh the cache.
• After 30 minutes (Expired): Executes query synchronously.

Summary

• Eliminates slow response times caused by cache expiration.
• Prevents database overloading from simultaneous cache misses.
• First array argument defines the fresh TTL and grace period TTL.