Tail Latency: Why the Slowest Requests Matter Most

What this post added

This post defines tail latency, explains its disproportionate impact in scaled systems due to fan-out, and lists common causes such as queueing, GC, disk I/O, lock contention, and noisy neighbors. It then positions in-memory architectures like Redis as a solution by removing disk I/O and GC pauses, and specifically mentions Redis 8's performance improvements and Redis Iris's semantic caching for AI workloads as examples of tail latency reduction.