Stampede Protection

A "Cache Stampede" occurs when a popular cache entry expires and hundreds of concurrent requests hit the database simultaneously to refresh it.

Request Coalescing

@express-route-cache prevents this by "coalescing" requests at the process level.

1. First Request: Hits a cache MISS. It starts executing the Express handler and stores a Promise in memory.
2. Subsequent Requests: If they arrive while the first request is still processing, they await the existing Promise instead of starting a new handler execution.
3. Completion: Once the first request finishes, all waiting requests resolve with the same data simultaneously.

Configuration

Stampede protection is enabled by default. You can toggle it if needed:

const cache = createCache({
  stampede: true, // Default
});