Databases & System Design•Part 4: In-Memory Caching & Fast Data Stores (Redis) (41 - 50)
Core Redis Data Structures:
In Simple Words:
- Strings: Caching API responses, counters (
INCR). - Hashes: Storing user objects (
HSET). - Lists: Queues (
LPUSH,RPOP). - Sets: Unique tags, mutual friends (
SADD,SINTER). - Sorted Sets (ZSET): Leaderboards, sliding window rate limiters (
ZADD).
bash
# Examples in redis-cli:
SET user:token:123 "session_payload" EX 3600
HSET user:profile:101 name "Alice" role "Admin"
LPUSH task_queue "job_id_55"
SADD active_users "user_1" "user_2"
ZADD leaderboard 1500 "PlayerA" 2300 "PlayerB"