Slow queries — sound familiar?
- ▸ Memory fragmentation drift —
mem_fragmentation_ratioclimbing past 1.5;activedefragtuning isn't reclaiming memory and you're force-restarting nodes during business hours. - ▸ KEYS / SCAN blocking writes — Operational scripts using KEYS at scale; single-threaded event loop blocked for seconds, all reads / writes stall, and migrating those scripts to SCAN keeps breaking edge cases.
- ▸ Eviction policy thrashing — allkeys-lru evicting the wrong keys because cardinality doesn't match access pattern; cache hit ratio collapsing from 95% to 70% under peak load and you can't identify the culprit keys.
JusDB performance consultants resolve all three in days, with a written tuning playbook. Book a tuning scoping call →
Valkey Performance Tuning
In short: Valkey performance tuning involves sizing maxmemory and selecting the right eviction policy per workload, choosing between RDB and AOF persistence for latency, detecting and remediating hot keys, batching with pipelines, scaling reads across replicas, and fixing memory fragmentation — to reach sub-millisecond p99 reads at scale.
Memory policies, eviction selection, persistence latency, pipeline batching, and hot-key remediation — the parameters that move p99 latency from 12ms to under 2ms and cut peak memory by 30-40%.
Where Valkey latency hides
Six tuning surfaces, each with measurable before/after. We instrument first, then change, then validate — never the other order.