Redis

First-principles depth — the single-threaded model, data structures, caching, persistence & scaling.

Lessons

0001 The single-threaded event loop
One thread, one queue — atomicity for free, and big-O as shared latency.
done
0002 Data structures by command complexity
Choosing string / hash / list / set / zset on cost, not habit.
done
0003 Key expiration: TTL vs eviction
Lazy + active expiry, and why a TTL is not the same as memory-pressure eviction.
done
0004 Cache-aside & the stampede problem
The canonical caching pattern, and the thundering herd when TTLs expire together.
done
0005 Persistence: RDB vs AOF
Snapshots vs the append log, and the fork()/copy-on-write trick that avoids blocking.
done
0006 Replication & async trade-offs
How a replica copies a primary, why it's asynchronous, and the failover story.
done
0007 Automatic failover: Sentinel & Cluster
Monitoring + promotion, and sharding across primaries with 16384 hash slots.
done
0008 Mixed interleaved review
A cross-lesson quiz spanning 0001–0007 to convert fluency into durable memory.
done

Reference

Glossary → Single-threaded model cheat sheet → Data structures cheat sheet → TTL vs eviction cheat sheet → Cache-aside & stampede cheat sheet → Persistence (RDB vs AOF) cheat sheet → Replication cheat sheet → Sentinel & Cluster cheat sheet → Retention plan →

These lessons have a teacher attached. Bring a real latency graph, a data-model question, or a fuzzy concept to your session and we'll dissect it together.