Redis TTL Deep Dive in 7 min: SET EX, Sliding Sessions, Cache-Aside
Every Redis value lives under a key. TTL gives that key an automatic expiration date.
This Runtime Atlas lesson covers key naming, SET/GET/DEL/EXISTS/TYPE, EXPIRE and SET … EX, sliding session expiry, cache-aside with TTL, why overwrites can drop TTL, and why SCAN beats KEYS in production.
This video covers:
Why key design matters (namespaces)
Core key operations: SET, GET, DEL, EXISTS, TYPE
What TTL / PTTL really return (−1 vs −2)
OTP example with SET … EX
Sliding expiry for sessions
Cache-aside with TTL
KEYS vs SCAN in production
Common mistakes checklist
Chapters:
0:00 Keys, TTL & Expiry
0:22 Why Key Design Matters
0:48 Good Key Naming Patterns
1:12 Core Key Operations
1:33 DEL and Safe Deletion Habits
1:54 What TTL Really Means
2:17 SET With EX — OTP Example
2:45 EXPIRE, PEXPIRE, and SET Options
3:10 Sliding Expiry for Sessions
3:37 Cache-Aside With TTL
4:01 Overwriting a Key Can Drop TTL
4:23 KEYS vs SCAN in Production
4:49 PERSIST, RENAME, and Key Hygiene
5:15 TTL vs Eviction Policies
5:39 Common Mistakes Checklist
6:07 Recap
Series: Redis Complete Course (Runtime Atlas)
Previous: What Is Redis?
Next: Strings, Counters & Feature Flags
#Redis #TTL #Backend #SystemDesign #RuntimeAtlas #Caching #Sessions