Redis 7.2 and WordPress
Redis 7.2 introduced changes that directly benefit high-concurrency WordPress deployments: improved memory efficiency, faster RDB saves, and better command-level ACL controls. For WordPress object caching, these improvements reduce cache eviction storms during traffic spikes.
The High-Concurrency Problem
At low traffic, Redis works seamlessly. During traffic spikes, issues emerge: cache stampedes (simultaneous misses trigger parallel DB queries), memory pressure eviction, and hot key contention. Redis 7.2’s improved listpack encoding reduces memory footprint by 15–25% for typical WordPress object cache workloads, allowing more data to fit within the maxmemory limit.
Optimal Redis Configuration
Set maxmemory to 75% of available RAM, use allkeys-lru for eviction policy, and enable AOF with every-second sync. Probabilistic early expiration can also be implemented in your object cache drop-in to prevent cache stampedes.