The original title is: "Database Rate Limiting: The Missing Piece After a Circuit Breaker"

Short summary

When Redis fails, a circuit breaker redirects requests to the database—but this can overwhelm it, since databases rarely handle full production load. Implement rate limiting at the application layer using token buckets to cap database requests at safe QPS levels. This ensures the system degrades gracefully during outages, protecting the database from cascading failure rather than serving every request.

• •Circuit breakers prevent failed cache calls; database rate limiters prevent cascade failures
• •Implement rate limiting inside the application, not the gateway—only the app knows which endpoints hit the database
• •Use token buckets to allocate QPS per app instance, e.g., 500 QPS × 10 servers = 5,000 QPS to database

Generated with AI, which can make mistakes.