foundation20m
Model Single-Node Key-Value Core
Model shared keyspace changes for SET, GET, and DEL in a Redis-like system.
Redis Tutorials
Model Redis one mechanism at a time.
Each tutorial gives you a short mechanism brief, practice checks, a starter D2 model, and feedback on the system behavior you submit.
What a fivenines problem looks like
Each problem focuses on one Redis-like runtime mechanism. You read the short theory, check the key behavior in practice, then produce one concrete D2 artifact: a sequence diagram, state machine, flowchart, data model, or architecture diagram.
The structure is fixed so you can focus on the mechanism instead of decoding the prompt. Every problem ships with a brief, requirements, constraints, starter files, hints, and a review rubric. Feedback points to missing runtime paths, broken invariants, and the next concrete revision.
Artifact types you will produce
- Sequence diagrams — trace a client command through parsing, execution, persistence, replication, or cluster routing.
- State machines — make parser states, transaction states, and failover transitions explicit.
- Flowcharts — model command dispatch, expiration, eviction, and other branch-heavy paths.
- Data models — show keyspace ownership, object metadata, dictionaries, logs, slots, and indexes.
- Architecture diagrams — compose learned subsystems without hiding the runtime path.
How feedback works
AI feedback checks your D2 source against the tutorial rubric and tells you what holds up, what is missing, and what breaks. The goal is not a generic grade; it is a sharper model of how Redis works inside.
foundation20m
Model RESP Protocol Parser
Model valid, incomplete, and invalid RESP parsing in a Redis-like system.
foundation25m
Model Client Connection Lifecycle
Model per-client input, output, mode, and cleanup state in a Redis-like system.
foundation25m
Model Event Loop
Model one event-loop turn across file readiness and time events in a Redis-like system.
foundation25m
Model Command Table And Dispatch
Model metadata-driven command dispatch before handler execution in a Redis-like system.
foundation20m
Model Redis Object Model
Model logical type, physical encoding, and object metadata in a Redis-like system.
foundation25m
Model Hash Table And Rehashing
Model two-table incremental rehashing behavior in a Redis-like system.
foundation25m
Model Expiration System
Model expiration metadata plus passive and active deletion in a Redis-like system.
foundation25m
Model Memory Limits And Eviction
Model maxmemory eviction decision flow in a Redis-like system.
foundation25m
Model Core Data Types
Model Redis type choice from access patterns in a Redis-like system.
intermediate25m
Model Pipelining And Output Buffers
Model transport batching, ordered replies, and partial writes in a Redis-like system.
intermediate30m
Model Transactions
Model per-client MULTI/EXEC queuing and WATCH invalidation in a Redis-like system.
intermediate25m
Model Scripts/functions
Model atomic server-side code execution and deterministic propagation in a Redis-like system.
intermediate25m
Model Pub/Sub
Model live Pub/Sub fanout without durable storage in a Redis-like system.
intermediate30m
Model Streams
Model streams as replayable logs with consumer group pending state in a Redis-like system.
intermediate30m
Model RDB Snapshotting
Model point-in-time RDB snapshotting with copy-on-write in a Redis-like system.
intermediate30m
Model AOF Persistence
Model AOF durability timing and rewrite compaction in a Redis-like system.
intermediate30m
Model Startup Recovery
Model startup rebuild from RDB or AOF before normal traffic in a Redis-like system.
advanced30m
Model Replication: Full Sync
Model full sync using a snapshot plus writes after the snapshot point in a Redis-like system.
advanced30m
Model Replication: Partial Sync
Model partial sync using replication ID, offset, and backlog range in a Redis-like system.
advanced30m
Model Failover Controller
Model distributed failover decision, promotion, epochs, and reconfiguration in a Redis-like system.
advanced30m
Model Cluster Sharding
Model cluster slot routing, MOVED, and cross-slot rejection in a Redis-like system.
advanced30m
Model Cluster Resharding
Model temporary ASK routing while a slot is being migrated in a Redis-like system.
advanced30m
Model track Redis-Like System
Model the complete Redis-like command path with learned subsystems attached in a Redis-like system.