tech-studies

Redis

2 min read

Redis

roadmap.sh: https://roadmap.sh/redis

Suggested path through the Redis nodes. Each node links to its lesson when written.

Nodes

Introduction

  • What is Redis?
  • In-memory vs On-disk databases
  • Redis vs Memcached
  • Use cases for Redis
  • Installing Redis
  • redis-cli basics
  • RESP protocol

Data Types

  • Strings
  • Lists
  • Sets
  • Sorted Sets
  • Hashes
  • Bitmaps
  • HyperLogLog
  • Geospatial indexes
  • Streams
  • Bitfields
  • JSON (RedisJSON)

Core Commands & Concepts

  • Key naming conventions
  • Key expiration (TTL)
  • SCAN vs KEYS
  • Pipelining
  • Transactions (MULTI / EXEC / WATCH)
  • Lua scripting (EVAL)
  • Functions
  • Pub/Sub
  • Keyspace notifications

Memory Management

  • Maxmemory directive
  • Eviction policies (LRU / LFU / TTL)
  • Memory optimization & encoding
  • Memory analysis (MEMORY USAGE / redis-cli —bigkeys)
  • Object encoding internals

Persistence

  • RDB snapshots
  • AOF (Append Only File)
  • AOF rewrite
  • RDB + AOF hybrid persistence
  • Backup & restore strategies

Replication & High Availability

  • Master-replica replication
  • Replication internals (PSYNC)
  • Redis Sentinel
  • Automatic failover
  • Read scaling with replicas

Scaling

  • Redis Cluster
  • Hash slots & sharding
  • Cluster resharding
  • Client-side partitioning
  • Proxy-based partitioning (Twemproxy / Envoy)

Performance & Benchmarking

  • redis-benchmark
  • Latency monitoring (LATENCY / SLOWLOG)
  • Connection pooling
  • Avoiding blocking commands
  • Hot key & big key mitigation

Security

  • Authentication (requirepass / AUTH)
  • ACLs (Access Control Lists)
  • TLS / SSL encryption
  • Protected mode & network binding
  • Command renaming / disabling

Common Use Cases

  • Caching (cache-aside, write-through)
  • Session store
  • Rate limiting
  • Leaderboards
  • Message queues
  • Distributed locks (Redlock)
  • Real-time analytics

Administration & Observability

  • Configuration (redis.conf)
  • INFO command & metrics
  • Monitoring (Prometheus / RedisInsight)
  • Logging
  • Upgrading Redis
  • Running Redis in Docker / Kubernetes

Client Libraries & Ecosystem

  • Client libraries (redis-py, ioredis, Jedis, Lettuce)
  • Redis Stack
  • RediSearch
  • RedisTimeSeries
  • RedisBloom
  • Managed Redis (ElastiCache, Redis Cloud)

Resources

See resources.md.

Project ideas

  • Build a cache-aside layer in front of a SQL database and measure the latency / hit-ratio improvement under load.
  • Implement a sliding-window rate limiter using sorted sets and expose it as middleware for a small REST API.
  • Stand up a 3-node Redis Cluster in Docker, write a script that triggers resharding, and verify zero key loss during the migration.

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