Drills

Invalidate cached data safely after writes

Explains delete-on-write, versioned keys, event-driven invalidation, and the race conditions around cache freshness.

Concept questionEasy~5 min

Measure cache health beyond hit rate

Explains cache observability across hit rate, latency, source load, memory, evictions, stale data, and fallback behavior.

.NETASP.NET CoreAzureAzure Cache for RedisRedis+1

Prevent a cache stampede on hot keys

Explains what happens when a hot key expires and how request coalescing, TTL jitter, background refresh, and stale serving help.

.NETASP.NET CoreAzureAzure Cache for RedisRedis+1

Reuse StackExchange.Redis connections and set sane timeouts

Explains why Redis connections are reused, how timeouts protect API threads, and how to diagnose client-side Redis pressure.

Serialize and version cached Redis values safely

Explains cached value serialization, schema versioning, deploy compatibility, and safe handling of old payloads.

.NETASP.NET CoreAzureAzure Cache for RedisRedis+1

Store session state safely in scaled-out ASP.NET Core

Explains session state choices for scaled-out ASP.NET Core APIs and when Redis-backed state is appropriate.

Concept questionEasy~5 min

Use cache-aside for a read-heavy API endpoint

Explains the cache-aside pattern for read-heavy endpoints and how misses, TTLs, and source-of-truth reads fit together.

Concept questionHard~9 min

Use capacity, load shedding, and backpressure signals

Explains saturation signals and how systems shed, queue, throttle, or degrade before cascading failure.

.NETApplication InsightsASP.NET CoreAzure Service BusEF Core+4

Use Redis counters for API rate limiting

Explains Redis-backed rate-limit counters, atomic increments, windows, identity keys, and fallback behavior.

Concept questionHard~9 min

Use Redis locks only with clear lease boundaries

Explains the risks of Redis-based distributed locks and when database constraints, queues, or idempotency are safer.