Topic 16.2
Intermediate Questions (16–35)
In one line
Twenty implement-and-explain questions: cache-aside, rate limiting, counters, leaderboards, sessions, locks, stampede, penetration, avalanche, hot and big keys, Cluster, Sentinel, replica lag, stale reads, Pub/Sub, Streams, Streams vs Kafka, List vs Stream, MULTI/EXEC vs Lua.
Think of it like this
A cooking exam where you're asked to actually make the dish, not describe it. Intermediate questions expect working designs with the exact commands and the failure that the naive version has.
Key ideas
- 01
Answer shape: naive version → what breaks → correct version with commands → one production concern (scale, failure or monitoring).
- 02
These map to Phases 3, 5, 6, 7, 8, 10, 11, 12 and 13.
Explain it without notes
16. Implement cache-aside.
17. Implement a rate limiter.
18. Implement a distributed counter.
19. Implement a leaderboard.
20. Implement a session store.
21. Implement a distributed lock.
22. Explain cache stampede.
23. Explain cache penetration.
24. Explain cache avalanche.
25. Explain hot keys.
26. Explain big keys.
27. Explain Redis Cluster.
28. Explain Sentinel.
29. Explain replica lag.
30. Explain stale reads.
31. Explain Pub/Sub.
32. Explain Streams.
33. Redis Streams vs Kafka?
34. Redis List vs Streams for queues?
35. MULTI/EXEC vs Lua?
Practice
Pick three questions and write the full Redis commands or Lua for each from memory.
Done when you can
I can implement and explain all 20 intermediate questions with commands and failure modes.