Distributed Systems & System Design
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6 questions
Clear filtersCaching & Performance · Senior
The price changed. Why did the old price come back?Recognize a read-fill/invalidation interleaving and select a freshness contract with correctly preserved ordering evidence.
Caching & Performance · Staff
One key expired. Why did database reads surge?Turn an expired hot key from a database stampede into bounded refill work, with explicit failure and staleness policies.
Caching & Performance · Senior
Hit rate fell from 95% to 80%. Why did the database suddenly struggle?Translate a percentage-point hit-rate regression into origin demand, then diagnose workload and key-distribution causes.
Caching & Performance · Staff
The IDs do not exist. Why are they melting the database?Protect misses for absent keys using validation, scoped negative caching, optional membership filters and a safe creation freshness contract.
Caching & Performance · Staff
The cache was fast. Why did one customer see another customer's orders?Treat cached identity as part of the authorization boundary, applying HTTP shared-cache rules to personalized responses.
Caching & Performance · Principal
Every cache node restarted. Why did adding capacity make recovery worse?Classify cache as a capacity dependency and design bounded recovery when the entire working set is cold.