Interview › Databases & Caching
How do you handle cache warming after a restart or failover?
Databases & Caching · Advanced level
Answer
Cache warming preloads hot keys after restart, failover, or new cluster creation so user traffic does not create a cold-cache miss storm. It must be throttled and monitored to avoid overloading the database.
Technical explanation
Cold caches can shift traffic to RDS and create a secondary outage.
Warm only known hot keys and throttle the job.
Stop warming if source DB or application SLOs degrade.
Hands-on example
Warmup job:
for key in $(cat top_keys.txt); do curl -s "https://product-service/internal/cache-warm?key=$key" >/dev/null; sleep 0.05; done
Stop if RDS CPU > 70% or app p95 exceeds SLO.Preparing for an interview?
Check how well your resume matches the role with our free resume checker— match score, ATS check, and the skills you're missing.
More Databases & Caching interview questions
- What is Amazon RDS, and what does it manage for you versus self-managed databases?
- What database engines does RDS support?
- What is the difference between RDS and Aurora?
- What is Multi-AZ in RDS, and how does automatic failover work?
- How long does an RDS Multi-AZ failover typically take, and what triggers it?
- What is the difference between Multi-AZ and a read replica?
- When would you use a read replica, and can it become a standalone database?
- Can a read replica be in a different region, and why would you do that?